Ambiguous Cause-in-Fact and Structured Causation: A Multi-Jurisdictional Approach

Ambiguous Cause-in-Fact and Structured Causation: A Multi-Jurisdictional Approach ERIK S. KNUTSEN SUMMARY I. INTRODUCTION... 250 II. THE LANDSCAPE OF CAUSE-IN-FACT DOCTRINE... 251 A. The Evolution of Cause-in-Fact Doctrine... 252 1. The But For Test... 252 2. The Substantial Factor or Material Contribution to Injury Test... 253 B. Ambiguous Cause-in-Fact Cases... 254 C. Modifications to Traditional Cause-in-Fact Tests... 256 1. The Reversal Approach: Reversing the Burden of Proof of Causation to the Defendant... 256 2. The Increased Risk Approach: Proving the Defendant Materially Increased the Risk of Injury... 257 3. The Inference Approach: Inferring Causation from the Facts of the Case... 258 D. The Importance of Ambiguous Cause-in-Fact Cases: Hints of Policy and Theory... 258 1. Policy Drives Modifications to Traditional Cause-in-Fact Principles... 258 2. The Inherent Indeterminacy of Cause-in-Fact Cases... 260 3. Theory Behind the Policy of Cause-in-Fact... 261 III. MODIFICATIONS TO TRADITIONAL CAUSE-IN-FACT DOCTRINE... 262 A. The Reversal Approach... 262 1. The Genesis of the Reversal Approach... 263 2. Criticisms of the Reversal Approach... 266 B. The Increased Risk Approach... 267 1. The Genesis of the Increased Risk Approach... 268 a. The Increased Risk Increased Injury Dichotomy in Britain and Canada... 268 b. The Increased Risk Approach in the United States... 271 2. Criticisms of the Increased Risk Approach... 272 3. Alternatives to the Increased Risk Approach... 273 a. Probabilistic Evidence, Efficiency, and Increased Risk... 273 b. Increased Risk of Injury as a Compensable Injury... 275 C. The Inference Approach... 277 Erik S. Knutsen, LL.M., Harvard Law School; LL.B., Osgoode Hall Law School; H.B.A., Lakehead University. Former Visiting Assistant Professor, Florida State University College of Law. The author wishes to thank Professor Jon Hanson of Harvard Law School for helpful comments and guidance in the early stages of this article and for continued mentorship, especially in the area of tort law. The author also wishes to thank Professor Paul C. Weiler, Henry J. Friendly Professor of Harvard Law School, for instilling both a critical approach to the torts system as well as the recognition of the value of cross-jurisdictional, comparative approaches. 249

250 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 1. Res Ipsa Loquitur and the Inference Approach...277 2. The Genesis of the Inference Approach...278 3. Criticisms of the Inference Approach...280 IV. A NEW APPROACH TO AMBIGUOUS CAUSE-IN-FACT CASES...282 A. Structured Causation...283 B. Reversing the Burden of Proof of Causation to Force Information...283 C. Materially Increasing the Risk of Injury as Proof of Cause-in-Fact...284 V. EVALUATING STRUCTURED CAUSATION...284 A. Structured Causation Compatible with Corrective Justice View...284 B. Structured Causation Compatible with Efficiency Theory View...286 VI. CONCLUSION...288 I. INTRODUCTION It has been repeatedly asserted by tort scholars that, unlike proximate cause inquiries, an inquiry into cause-in-fact is a straightforward, factual matter devoid of policy. 1 That is a myth. 2 Over the past one hundred years, courts in the United States, Canada, and Britain have wrestled with doctrinal solutions for solving difficult torts cases turning on cause-infact. Courts have traditionally applied the but for, or sine qua non, test of cause-in-fact when faced with determining cause in a torts action. Where the but for test fails, courts have reached for the substantial factor, or material contribution to injury, approach to divine what role a defendant had in causing injury to a plaintiff. The majority of cause-infact questions that come before a court can be solved using either one of these two approaches. However, there exists a pattern of torts cases where courts have found both the but for test and substantial factor test unsatisfactory. These cases are unique in that they tend to exhibit a peculiar set of facts, which makes determining a breach of the standard of care possible but determining cause-in-fact nearly impossible. For example, a doctor s negligence in prescribing the incorrect treatment for an already ill patient may be a possible cause of the subsequent death of the patient. However, the death may also have been caused by the already existing illness a non-culpable, possible cause. Often there is no way to pinpoint the actual cause of injury. All that is known is that the defendant s negligence increased the risk that the plaintiff s injury might occur. A fact finder is faced with the difficult decision of whether or not to award compensation to a plaintiff who has been exposed to a risk of injury created by a defendant s negligence but who may possibly have been injured by a cause not related to the defendant s negligence. Cause-in-fact is ambiguous. 1. See, e.g., Richard W. Wright, Causation in Tort Law, 73 CAL. L. REV. 1735, 1737 (1985) [hereinafter Wright, Causation in Tort Law] (capsulizing this trend, beginning with Prosser s comment that causation is the simplest and most obvious problem when determining tortious liability). For similar explanations about the apparent simplicity of causation, see also W. PAGE KEETON ET AL., PROSSER AND KEETON ON THE LAW OF TORTS (5th ed. 1984); H.L.A. HART & TONY HONORÉ, CAUSATION IN THE LAW (2d ed. 1985); JOHN G. FLEMING, THE LAW OF TORTS (9th ed. 1998) [hereinafter FLEMING, THE LAW OF TORTS]. 2. Indeed, torts scholars have echoed this belief for some time, beginning with Wex S. Malone, Ruminations on Cause-in-Fact, 9 STAN. L. REV. 60 (1957), and Leon Green, The Causal Relation Issue in Negligence Law, 60 MICH. L. REV. 543 (1962). See also Wright, Causation in Tort Law, supra note 1, for another capsulization of this theoretical movement.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 251 These types of cases nag at one s sense of justice and are problematic for courts expected to apply predictable, rational legal principles. If, out of a set of two or more competing, independent possible causes, the plaintiff cannot definitively prove on a balance of probabilities that one competing independent cause of her injury is the defendant s negligence, the plaintiff cannot succeed on traditional cause-in-fact principles. Yet, when a plaintiff can establish that the defendant s conduct fell below the applicable standard of care, some courts in the United States, Canada, and Britain have refused to rob the plaintiff of an opportunity to prove causation and have modified cause-in-fact doctrine to accommodate the plaintiff. Three methods that courts use to aid a plaintiff have emerged through various courts continued exposure to these types of cases: (1) a court could reverse the burden of proof of causation to the defendant to disprove causation; (2) a court could infer causation based on a reasonable conclusion on the facts of the case; or (3) a court could hold the defendant liable for materially increasing the risk of injury to the plaintiff. Because these methods depart from traditional, established torts doctrine, each of these solutions owes its existence to subtle, competing policy considerations. Understanding the application of judicially created cause-in-fact doctrine to a case where proof of cause is at best ambiguous, necessitates understanding what has driven the court to tinker with existing tort doctrine in the first place. It is the aim of this article to explore how these three modifications to traditional cause-in-fact principles operate, examine why they arose, and then use a normative lens to evaluate why they need to be consolidated into a predictable and portable outgrowth of causation doctrine. This article is divided into four substantive sections. Part II defines the landscape of cause-in-fact doctrine and explains how American, Canadian, and British courts have modified this landscape to oblige ambiguous causation cases. Part III evaluates the judicial modifications of cause-in-fact doctrine and explores the often unarticulated motivations that drive a court s use of these innovations. First, reversal of the burden of proof of causation from the plaintiff to the defendant is considered. Next, the approach that proves cause based on the defendant s material increase of risk of injury to the plaintiff is evaluated. And finally, the practice of proving causation based on reasonable inferences on the facts of the case is examined. Part IV is the pivotal division of the article, where the three alternative approaches to cause-in-fact are synthesized to produce a new, normative 3 method for deciding ambiguous cause-in-fact cases. This method, called structured causation, reifies existing torts principles in a fashion that is also compatible with a positivist interpretation of what courts have been doing. Part V explains how structured causation accomplishes the normative goals, which are compatible with the competing tort theories of efficiency and corrective justice. II. THE LANDSCAPE OF CAUSE-IN-FACT DOCTRINE Courts in the United States, Canada, and Britain have long struggled with the slippery concept of causation. Legal doctrine has been shaped over the years to assist fact finders in determining the answer to the crucial question in a negligence action: What made this incident happen? An automobile accident could be caused by icy road conditions, faulty 3. In an effort to simplify the goals of this article, and with apologies to legal philosophers for glancing over the intricacies of each term, the term normative is used throughout this article in its generally applicable sense as describing what ought to be a prescriptive fix for the law. The term positivist is used in its generally applicable sense as what is, or as an explanation for, how the law operates now and has operated in the past. For an excellent parlay into the significance of these terms in relation to the circular nature of causation in tort law, see Richard Fumerton & Ken Kress, Causation and the Law: Preemption, Lawful Sufficiency, and Causal Sufficiency, 64 LAW AND CONTEMP. PROB. 83, 83 89 (2001).

252 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 brakes on the automobile, or the driver speeding through a stoplight without stopping. If the defendant s negligence is found to be a cause of the plaintiff s injury, then the defendant is held liable and must compensate the plaintiff. Causation is comprised of two components which are applied in succession in a negligence action to determine whether or not the defendant s negligence was the responsible cause of the plaintiff s injury. The first component, cause-in-fact, involves determining whether or not a defendant s negligence was a de facto cause of the plaintiff s injuries. In other words, cause-in-fact determines whether, but for the defendant s negligence, the plaintiff would have suffered the injury. The second causal component, proximate cause, involves determining whether or not the defendant s negligence is too remotely connected to the plaintiff s injury to be a foreseeable cause of that injury. 4 Proximate cause is an admittedly complex and policy-laden concept, which has plagued legal scholars for some time. 5 This article is concerned with the modifications and application of cause-in-fact doctrine only. Cause-in-fact is traditionally considered to be less contentious and more predictable than proximate cause. Indeed, many torts scholars and fact finders argue that cause-in-fact is a straightforward question of common sense. 6 This paper aims to revise that tradition of thinking by proffering evidence that, in a certain subset of negligence actions, cause-in-fact doctrine has the potential to be just as contentious, unpredictable, and policy laden as its counterpart, proximate cause. The recognition of this phenomenon necessarily calls for a new, structured approach to determining causation in certain cases where cause-in-fact is at issue. A cross-jurisdictional comparative approach is adopted throughout the cause-in-fact analysis for three reasons. First, modifications to traditional judicial treatment of cause-infact have become more prevalent in the United States, Canada, and Great Britain in the past thirty years. This movement toward a more flexible causal doctrine may in fact stem from the utilization of a dated cause-in-fact doctrine in a world becoming increasingly more complex. Second, the three jurisdictions exhibit a surprisingly parallel evolution of causal doctrine and are not developing cause-in-fact modifications independently but in conjunction with each other. A study of one single jurisdiction is therefore unsatisfactory as courts often utilize precedents from all three jurisdictions when charting the course of cause-in-fact principles. And third, a comparison of each jurisdiction to the other can inform a workable approach toward cause-in-fact that may be utilized in all three jurisdictions. A. The Evolution of Cause-in-Fact Doctrine 1. The But For Test The majority of common law cause-in-fact inquiries involve a court s application of one of two well-established torts principles: the but for test or the substantial factor test of causation. The but for test is the simpler of the two and is used for the majority of 4. Indeed, in Canadian and British courts, the term foreseeability appears to be preferred over that of proximate cause. 5. The famous proximate cause case, Palsgraf v. Long Island R.R., 162 N.E. 99 (N.Y. 1928), has, on its own, sparked countless analyses from Dean Prosser, Palsgraf Revisited, 52 MICH. L. REV. 1 (1952) to Edward S. Adams, et al., At the End of Palsgraf, There is Chaos: An Assessment of Proximate Cause in Light of Chaos Theory, 59 U. PITT. L. REV. 507 (1998). 6. See, e.g., Wright, Causation in Tort Law, supra note 1, at 1737 40; KEETON ET AL., supra note 1; HART & HONORÉ, supra note 1, at 24; FLEMING, THE LAW OF TORTS, supra note 1, at 218 19.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 253 factual circumstances. A plaintiff in a negligence action must prove on a balance of probabilities that, but for the defendant s negligent conduct, the plaintiff would not have suffered injury. 7 Fact patterns which fit the but for test of causation are those where it can be established on a balance of probabilities that the defendant s negligence was a necessary component of the cause that gave rise to the plaintiff s injury. In most negligence actions where one plaintiff sues one negligent defendant, that defendant s negligence is usually one of two or more equally competing and mutually exclusive possible causes. A court weighs the evidence of causation to determine whether or not, on a balance of probabilities, it can be proven that the defendant caused the plaintiff s injury. 2. The Substantial Factor or Material Contribution to Injury Test Some causation matters do not properly fit a straightforward application of the but for test. The substantial factor test, or the material contribution to injury approach as it is called in Canada, is used primarily in cases where multiple possible causes for a plaintiff s injuries exist, each cause being sufficient on its own to have caused the alleged injury. 8 The causes can either be concurrent or successive, but they must be independently sufficient to have potentially caused the entire injury to the plaintiff. In these cases, the but for test does not work. It is circular for a court to ask whether or not but for one cause the plaintiff would not be injured because the other existing cause is still sufficient to have resulted in the injury. For example, the but for test is unworkable in sorting out the cause-in-fact of damage to a plaintiff s property resulting from two separately burning fires that converge together to cause indivisible damage. 9 If one fire is caused by the defendant s negligence and one is caused by natural circumstances, a court is not aided by asking whether, but for the one fire, the plaintiff would not have suffered damage. The second fire exists and makes dividing the source of causation impossible. Therefore, a court uses the substantial factor test of causation to determine if a defendant s negligent conduct was a material element, or substantial factor, in bringing about the injury of the plaintiff. The role of the defendant s negligence in bringing about this injury must be beyond the de minimus range in order to be considered the cause of the injury. Courts have relied predominantly on the but for test of causation and, in most cases, a fact finder has little difficulty in determining whether or not a defendant s negligence is, on a balance of probabilities, a cause-in-fact of a plaintiff s injury. The repeated use of this test, and its nearly automatic application with little explanation in court judgments, may 7. The but for test was enunciated in the United States in New York Cent. R.R. v. Grimstad, 264 F. 334 (2d Cir. 1920), in which a man drowned after falling off a boat that carried no life preservers. The court held that the boat owner was not liable. Id. at 335. Although the boat owner was negligent not to have life preservers on board, that negligence was not a but for cause of the death of the man. Id. The but for test is often invoked in Canadian cases, such as Kozak v. Funk (1995), 135 Sask. R. 81 (Sask. Q.B.), varied, (1997), 158 Sask. R. 283 (Sask. C.A.). The Kozak decision acknowledges the importation to Canada of Lord Denning s articulation of the but for test in the British decision, Cork v. Kirby MacLean, Ltd., [1952] 2 All E.R. 402 (C.A.). 8. For the American substantial factor test, see RESTATEMENT (SECOND) OF TORTS 431 (1965). The Supreme Court of Canada recently reaffirmed the material contribution to injury approach in a case involving multiple successive accidents. See Athey v. Leonati, [1996] 3 S.C.R. 458, in which the injured plaintiff, who suffered from a pre-existing degenerative back condition, was involved in two separate automobile accidents within two months time. The multiple accidents and pre-existing back condition were all potential causes for Athey s subsequent herniated spinal disc. Id. at 459. The Supreme Court of Canada awarded compensation to Athey and held that the defendant automobile drivers materially contributed to Athey s injury. Id. 9. These were the exact facts in Kingston v. Chicago & N.W. Ry., 211 N.W. 913 (Wis. 1927), in which the Wisconsin Supreme Court held that the negligent creation of one fire on the part of the defendant was a substantial factor in bringing about the damage to the plaintiff s property from the conjoining fires. Id. at 915.

254 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 have led some torts scholars to believe that the but for test was nothing more than a dry application of a legal principle to easily discernible facts at hand. Even with the more complicated substantial factor test, court rhetoric usually points to a relatively easy judgment call about whether or not a defendant s negligence was a material element in causing the plaintiff s injury. B. Ambiguous Cause-in-Fact Cases Courts have sometimes been faced with causal patterns where neither the but for test nor the substantial factor test of causation produce satisfactory results. There exists a specific subset of cause-in-fact cases where a court allows a plaintiff to recover even though she cannot prove on a balance of probabilities that the defendant s negligence was either a but for cause of her injury or a substantial factor in bringing about that injury. The factual structure of these cases centers first around a plaintiff being able to prove on a balance of probabilities that the defendant breached the applicable standard of care. Next, there must exist two or more competing but independent possible causal explanations for the resultant injury of the plaintiff. One possible cause must be a result of the defendant s negligence. The other possible cause, or causes, must result from some other factor unrelated to the defendant s conduct. Cause-in-fact may be said to be ambiguous. There must also be an admitted lack of sufficient evidence to tip the scales beyond a balance of probabilities; otherwise, the but for causation test comes into play. Finally, the plaintiff must show some evidence connecting the defendant s negligent behavior to the cause of her injury, although the evidence will not be substantial enough to prove that the defendant s negligent behavior was more likely than not the cause-in-fact of the injury. In other words, the plaintiff must prove that the defendant s negligence contributed to the global risk factors to which the plaintiff was exposed. The defendant s contribution to those global risk factors must exhibit a nature that would likely have aided in bringing about the particular kind of injury the plaintiff suffered. In these specific types of cases which turn on cause-in-fact, a plaintiff using the but for or substantial factor test would fail to prove the defendant was the cause-in-fact of her injury. Specific evidence of the source of cause as stemming from either the defendant s negligence or the other competing causal explanation is virtually nonexistent. However, the mere fact that the plaintiff can prove the defendant s breach of the standard of care, coupled with at least some evidence that suggests a connection between that breach and the cause of the particular injury suffered, often prompts a court to bend the rules of cause-in-fact in favor of the injured plaintiff. Courts of all jurisdictions sometimes seem loathe to deny compensation for a plaintiff in this circumstance. The severity of harm to the plaintiff, the amount of compensation sought, and the perceived undesirability of the negligence of the defendant are all factors that weigh into a court s causal determinations. The theoretical and resultant policy reasons behind this tendency will be explored throughout this article. What is important to note at this stage of the analysis is that courts have begun to shape alternative cause-in-fact doctrines to assist plaintiffs faced with these ambiguous cause-in-fact conundrums. Some examples are in order to demonstrate the precise fact pattern of what will be called ambiguous cause-in-fact cases. The key in recognizing an ambiguous cause-in-fact case is identifying the fact that prima facie evidence of the defendant s negligence as a cause-in-fact of the plaintiff s injury is as inconclusive and unavailable as evidence of an alternative possible cause-in-fact. In non-causal terms, no one knows, or will ever know, precisely what happened.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 255 In Haft v. Lone Palm Hotel, 10 a father and son were found mysteriously drowned in a pool operated by the defendant. The local statute mandated either lifeguard service or proper signage if no lifeguard was on duty. The defendant did not comply with either of these requirements, and there was no evidence as to how the deaths occurred. The California court broke with traditional torts principles and reversed the burden of proof of causation to the defendant, who then had to disprove his role in causing the accident. 11 This case fits the pattern of an ambiguous cause-in-fact scenario because the plaintiff can prove that the defendant was negligent but cannot precisely link that negligence to a morelikely-than-not cause of the injuries suffered. A court is therefore faced with two options. It can choose to compensate the plaintiff and accept that there exists a chance that perhaps the defendant really is not liable for the injury. Or, in the alternative, the court could deny compensation for the plaintiff, even though evidence of the defendant s negligence points to the negligent behavior being a possible cause of the injuries. The traditional torts principles of but for and substantial factor causation do not offer courts much assistance in cases like Haft. Courts must judge whether or not to modify cause-in-fact rules in the interest of compensating plaintiffs. Canadian courts are also challenged by ambiguous cause-in-fact cases. The Supreme Court of Canada in Snell v. Farrell 12 adopted a modified causation test in indemnifying the plaintiff in a medical malpractice action. The defendant, Dr. Farrell, negligently performed eye surgery on Mrs. Snell, a diabetic with a number of pre-existing health complications. During the surgery, Mrs. Snell suffered blindness in her one eye. She simultaneously experienced a stroke in that same eye, which could also have caused her blindness. Evidence at trial could not conclusively point to whether or not her blindness was caused by Dr. Farrell s negligence or by Mrs. Snell s deteriorating health condition. The Supreme Court of Canada bypassed the traditional but for test of causation and inferred causation on the part of Dr. Farrell. This case also fits the pattern of an ambiguous cause-in-fact scenario: Although the plaintiff could prove that the defendant s negligence contributed to the global risk factors for the particular type of injury suffered, she could not link that negligence to the actual cause of the injury. Both Dr. Farrell s negligence and Mrs. Snell s poor health were independent and equally plausible causes of Mrs. Snell s blindness. Similarly, British courts are tempted to bend the rules of causation in favor of plaintiffs in ambiguous cause-in-fact cases. The famous case of McGhee v. National Coal Board, 13 cited in precedents and scholarship in both Canada and the United States, involved the House of Lords innovative approach to solving the seeming unworkability of a causal scenario. 14 In McGhee, the plaintiff was a brick kiln worker who rode home from work every day caked in brick dust. He developed dermatitis and sued his employer. At issue was whether or not the cause-in-fact of the dermatitis was the employer s negligence in not providing shower facilities for its employees. There existed a possibility that the dermatitis was a result of some other non-negligent cause. Again, an application of the but for test left the plaintiff uncompensated and the negligent defendant unpunished because cause was ambiguous. The court therefore decided to indemnify the plaintiff and modify cause-in-fact doctrine to allow for recovery. The House of Lords decreed that the defendant had 10. 478 P.2d 465 (Cal. 1970). 11. This approach has since been rejected by the California Supreme Court for asbestos-related cancer injuries. The burden of proof remains with the plaintiff. See Rutherford v. Owens-Illinois, Inc., 941 P.2d 1203, 1206 (Cal. 1997). 12. [1990] 2 S.C.R. 311. 13. [1973] 1 W.L.R. 1 (H.L. 1972). 14. McGhee was recently upheld in principle by the House of Lords in Fairchild v. Glenhaven Funeral Servs. Ltd., [2002] 3 W.L.R. 89 (H.L.).

256 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 materially increased the risk of injury to the plaintiff and that this material increase of risk of injury was enough to deem that the defendant had caused the injury. 15 These three examples of ambiguous cause-in-fact cases demonstrate a recurring evidentiary pattern. They also demonstrate a strong desire on the part of fact finders to adjust legal doctrine to favor plaintiff recovery over allowing a negligent defendant to escape liability in the face of negligent conduct. Ambiguous cause-in-fact cases do not commonly arise in courts but are a unique subset of cases. However, they are more likely to work their way to trial as the characteristic lack of causal evidence makes settlement difficult. Furthermore, ambiguous cause-in-fact cases are doctrinally significant as courts shape causal policy while wrestling with whether or not to modify traditional tort principles. In other words, despite the small number of ambiguous cause-in-fact cases that do exist, much of the evolution of cause-infact principles results from the appearance of these cases in the court system. The increasing complexity of the causation disputes brought to court, coupled with the advancement of science and computer technology, may result in more ambiguous cause-infact cases being tried. Medical malpractice, computer negligence, and even automobile accident tort actions are all being affected by the increased availability of scientific evidence that may assist in proving cause-in-fact. However, the adversary system s usage of competing science and competing expert witnesses may be increasing not the ability to pinpoint cause-in-fact, but the tendency to prove that cause is only a matter of perspective, made up of shades of gray. This trend may actually prompt more and more cases to be characterized as ambiguous cause-in-fact cases because science has the ability to ferret out alternative competing possible causes for a plaintiff s injuries. This could also foster a parallel increase in courts utilization of modifications to traditional cause-in-fact doctrine. C. Modifications to Traditional Cause-in-Fact Tests Ambiguous cause-in-fact cases have spawned three judicial modifications to traditional cause-in-fact doctrine. 16 A brief introduction to the three modifications follows in order to flesh out the debate behind a fact finder s use of one competing cause-in-fact approach over another. Each approach will then be discussed and evaluated in detail. 1. The Reversal Approach: Reversing the Burden of Proof of Causation to the Defendant The first approach, as mentioned in Haft v. Lone Palm Hotel, 17 involves reversing the burden of proof of causation to the defendant. This requires the defendant to marshal evidence to disprove causation. If the defendant cannot prove that his negligence was not the cause of the plaintiff s injury, he is deemed to have caused the plaintiff s injury. This causal approach appears to be used most often when a fact finder determines that a defendant will likely have more information about causation than would the plaintiff. The approach owes its origin to those cases of multiple defendants acting together to cause a 15. McGhee, [1973] 1 W.L.R. at 6. Lord Wilberforce went further than the rest of the House of Lords and seemed to advocate a reversal of the burden of proof of causation to the defendant. Id. at 7. 16. Lewis Klar notes that the law has three options when the but for and substantial factor tests fail: (1) the law can redefine the nature of cause and modify the but for test or ignore it; (2) the law can shift the onus for the burden of proof of causation or require something less than a balance of probabilities to prove causation; or (3) the law can redefine the nature of the plaintiff s injury. LEWIS KLAR, TORT LAW 324 (2d ed. 1996) [hereinafter KLAR, TORT LAW]. 17. 478 P.2d 465 (Cal. 1970).

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 257 single, indivisible harm, such as two hunters negligently and simultaneously firing upon one plaintiff. 18 The reasoning behind the court s departure from traditional tort principles rests on the belief that the plaintiff was robbed of the ability to prove causation because the defendant s negligence destroyed that proof. For example, in a medical malpractice ambiguous cause-in-fact case, the burden of proof of causation may be reversed to the defendant hospital when the hospital s nursing team fails to properly maintain the patient s medical chart, thereby resulting in that patient receiving substandard medical treatment. 19 2. The Increased Risk Approach: Proving the Defendant Materially Increased the Risk of Injury The second modification to traditional cause-in-fact principles first appeared in the McGhee v. National Coal Board 20 case. There, the majority of the House of Lords determined that a defendant employer s negligence was the cause-in-fact of the plaintiff s injuries if the plaintiff could prove that the defendant materially contributed to the injury of the plaintiff. 21 A material contribution to an injury was held to be synonymous with saying that the defendant materially contributed to the risk of injury. Lord Wilberforce went further to state that if a plaintiff proved the defendant materially contributed to the risk of injury occurring, the burden of proof on the causation issue shifted to the defendant. 22 Lord Wilberforce s modification of cause-in-fact doctrine combines the reversal approach with a novel material contribution to the risk of injury approach. A surprising number of courts in Canada, the United States, and Britain adopted causal doctrines similar to that espoused by Lord Wilberforce, which allow a plaintiff to prove cause-in-fact based on evidence of the defendant materially increasing the risk of injury to the plaintiff. Unlike the majority of the House of Lords, some courts made a distinction between materially increasing the risk of injury and materially contributing to the injury itself. 23 The increased risk approach was seen as a flexible, discretionary method for dealing with ambiguous cause-in-fact cases. A smaller number of courts also utilized the reversal approach in conjunction with the increased risk approach, keeping more closely with Lord Wilberforce s original concept. 18. Compare Summers v. Tice, 199 P.2d 1 (Cal. 1948), with Cook v. Lewis, [1951] S.C.R. 830 (nearly identical U.S. and Canadian decisions). 19. This was the fact situation in Joseph Brant Mem l Hosp. v. Koziol, [1978] S.C.R. 491. However, the Supreme Court of Canada overruled the Ontario Court of Appeal s use of Cook v. Lewis, [1951] S.C.R. 830, to reverse the burden of proof to the nursing staff. Joseph Brant Mem l Hosp., [1978] S.C.R. at 501. See also Look v. Himel, [1990] O.J. No. 1073 (Ont. Gen. Div.), available at 1991 WL 1142616, and Pike v. Peace Arch Dist. Hosp. Soc y, [1985] 33 A.C.W.S.2d 490 (B.C.), available at 1985 A.C.W.S.J. Lexis 21146, where Canadian courts have entertained but rejected the reversal idea in cases involving negligent upkeep of hospital notes. A similar type of reversal did in fact occur in the American case of Ybarra v. Spangard, 154 P.2d 687 (Cal. 1944), where the court used the doctrine of res ipsa loquitur to, in effect, reverse the burden of proof of causation to the defendant physicians. See infra Part III.C for a discussion of the conceptual differences between the inference approach to cause-in-fact and using res ipsa loquitur to make determinations based on circumstantial evidence. 20. [1973] 1 W.L.R. 1 (H.L. 1972). 21. Id. The speeches of Lord Reid, Lord Simon of Glaisdale, Lord Salmon, and Lord Kilbrandon discuss the increased risk approach as functionally equivalent to the substantial factor, or material contribution to injury test. See infra Part II.A for a discussion of the fundamental difference between basing cause on increase of risk, as opposed to mere presence of an alternative but independently sufficient cause. Courts in Canada and Britain have erroneously blurred the distinction between the two concepts. 22. McGhee, [1973] 1 W.L.R. at 22 23. 23. For a complete discussion of the cases exhibiting this trend, see infra Part III.B.1.

258 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 3. The Inference Approach: Inferring Causation from the Facts of the Case The third approach to ambiguous cause-in-fact cases, as demonstrated in cases like Snell v. Farrell, 24 has become the dominant method for dealing with ambiguous cause-infact cases. If a plaintiff can prove that a defendant was negligent but cannot also prove that the negligence was, on a balance of probabilities, a but for cause of the injury, courts have allowed a plaintiff to recover, provided that the plaintiff s evidence nearly establishes but for causation. If the evidence comes close to proving causation on a balance of probabilities, a court may infer causation on the part of the defendant. U.S., Canadian, and British courts use these causal inferences in situations when the defendant is allowed to escape liability despite the existence of some positive evidence that indicates the defendant s negligence may be a possible cause of the plaintiff s injury. A difficulty with this incarnation of cause-in-fact doctrine is that it is relatively unstructured and unpredictable, leaving a great deal of discretion to the fact finder and his or her evaluation of both the sufficiency of the evidence and the relative wrongdoing of the defendant. D. The Importance of Ambiguous Cause-in-Fact Cases: Hints of Policy and Theory Before discussing in detail the three approaches to ambiguous cause-in-fact cases, it is important to at least briefly introduce the subtle theoretical and policy subtexts at work that steer each approach. 1. Policy Drives Modifications to Traditional Cause-in-Fact Principles A preliminary question that must be answered is: Why modify traditional cause-infact principles in the first place (i.e., what is the normative goal to be gained)? It has been shown that the particular fact circumstances of ambiguous cause-in-fact cases render the but for or substantial factor tests of causation unworkable and deny compensation to the plaintiff. Because there are two independent, competing alternative causes of a plaintiff s injury, one cannot say but for one cause, the plaintiff would not have been injured. The existence of the second alternative cause negates the answer: But for the negligent cause, the other non-negligent cause still exists as a potential source for the injury. Similarly, the defendant s negligence cannot be a substantial factor in the cause of injury because the two competing possible causes are independently exclusive of one another. Either one possible cause was the source of the injury or the other one was. Therefore, an application of either test leaves a plaintiff uncompensated, even though it is clear that the defendant created a risk of a specific injury and the plaintiff was exposed to that risk and suffered the specific injury. Something troubles most courts faced with ambiguous cause-in-fact cases, which prompts them to attempt to assist the plaintiff through a modified causation standard. It likely stems from the fact that the plaintiff can prove that the defendant behaved negligently. A court must choose between the lesser of two evils: compensate the plaintiff or allow the negligent defendant to escape liability. There is a powerful unsettling rhetoric at work in permitting the negligent defendant to escape liability, through no fault of the plaintiff, merely because proof of causation does not quite meet a balance of probabilities standard. It is no wonder that a court most often chooses to side with the plaintiff. Yet, in doing so, a court must make a decision based not on the facts presented but on pure policy. 24. [1990] 2 S.C.R. 311.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 259 As Nancy Lee Firak notes, the policy furthered is this: [T]hat plaintiff, having suffered a recognized injury should be entitled to compensation; and that defendant, having created a risk of the kind that injured plaintiff, should bear the cost of compensation. 25 Cause-in-fact decisions based on normative policy are anathema to some torts scholars. Indeed, many insist that policy-based cause-in-fact determinations cannot exist. But ambiguous cause-in-fact cases stand as a definitive example that, sometimes, cause-infact decisions can be based purely on policy. Dean Prosser, 26 John Fleming, 27 and Leon Green 28 have advocated that cause-in-fact determinations are factual decisions where evidence is simply applied to traditional causation doctrine. H.L.A. Hart and Tony Honoré argue that layperson common sense guides cause-in-fact decisions, and no policy is ever invoked. Richard Wright attempts to create a non-normative tool for analyzing cause-infact. 29 Yet all these notions appear to ignore the practical reality that courts are bending traditional rules to accommodate ambiguous causation cases. The fecundity of discretion embodied in these ambiguous causation cases demonstrates that courts do resort to policy decisions where a straightforward factual application of traditional principles falls short of a court s perceived goal. It should be noted that, despite recent modifications to causal doctrine, not all ambiguous cause-in-fact cases are resolved in favor of the plaintiff. In Knotterus v. North Park Street Railway Co., 30 a roller coaster derailed, causing injuries to the plaintiff. There was evidence that the derailment could have been caused by a large wood chip which the wind had blown from an area where the defendant s employees were performing construction work. Alternatively, there was evidence that the derailment may have been caused by defective work performed by the owner of the amusement ride who was not a party to the action. The evidence adduced proved neither cause beyond a balance of probabilities, but both the trial and appellate courts found for the defendant. Thus, the apparent lack of predictability in this subset of causation cases further underlines that courts are basing their decisions on some unarticulated justice goals. An increasing reliance on normative policy to solve difficult causation issues has been demonstrated in most ambiguous cause-in-fact cases. This tendency will become lucid in the ensuing analysis of the specific methods of dealing with ambiguous cause-in-fact cases. Wex Malone argues that cause-in-fact is not some dry, calculable thing but full of policy. 31 His belief in the inextricable tie between normative policy and cause-in-fact has been echoed by Guido Calabresi, 32 D.M.A. Strachan, 33 John Borgo, 34 and Harper, James and 25. Nancy Lee Firak, Alternative Forms of Liability: Developing Policy Aspects of the Cause-in-Fact Requirement of Tort Law, 20 ARIZ. ST. L.J. 1041, 1068 (1988). 26. See PROSSER, supra note 1, at 23 24. 27. See FLEMING, THE LAW OF TORTS, supra note 1, at 218 19. 28. See Green, supra note 2, at 548 52. 29. This test, called the NESS (Necessary Element of a Sufficient Set) test, requires that, in order to hold a particular event in a causal chain as the cause, it must be a necessary element in that chain which brought about the plaintiff s particular injury. Richard Wright, Causation, Responsibility, Risk, Probability, Naked Statistics, and Proof: Pruning the Bramble Bush by Clarifying the Concepts, 73 IOWA L. REV. 1001, 1019 (1988) [hereinafter Wright, Clarifying the Concepts]. Wright s formulaic approach to cause-in-fact is criticized by Richard Fumerton and Ken Kress as giving the appearance of being a non-normative prescription to causation, but, in fact, Wright s approach is just as normative as that which it hopes to replace. Fumerton and Kress argue that the very idea of lawful sufficiency is itself subjective. One presupposes the other. See generally Fumerton & Kress, supra note 3. 30. 53 N.W. 529 (Mich. 1892). 31. Malone, supra note 2, at 64. 32. Guido Calabresi, Concerning Cause and the Law of Torts: An Essay for Harry Kalven, Jr., 43 U. CHI. L. REV. 69, 106 07 (1975).

260 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 Grey. 35 Each commentator stresses that courts base causal decisions on policy considerations such as perceived efficiency, deterrence considerations, compensation goals, or the desire to redress a perceived wrongdoing. The rise of alternative modes of proving causation beyond the traditional but for test may be a renewed recognition of the importance of maintaining the above stated policy goals in an increasingly complex world. But for causation is becoming increasingly more difficult to prove in court as science and technology create not more certainty in causal evidence, but more shades of grey. 36 There is a corresponding need to increase regulation of new activities which impose risk of harm as a byproduct of scientific advancement. The tort system serves as a malleable method of regulating these new industries. As a result, unlike scientific causality, legal causality is becoming easier to prove in order to have the tort system serve this regulatory function by imposing liability on negligent defendants. Furthermore, the reverberative effect of the law and economics movement may also be affecting the decline of strict proof of cause. Law and economics characterizes causation as less of a determinative element in an efficient tort system than, for example, an applicable liability standard of either negligence or strict liability. 37 All these factors combine to create a normative, judicially created causal doctrine. 2. The Inherent Indeterminacy of Cause-in-Fact Cases The three judicial modifications to the traditional but for test of causation are rife with policy underpinnings. Each approach allows a great deal of judicial discretion. What is most curious is that a court does not usually articulate the reasoning behind the application of modified rules of causation in ambiguous cause-in-fact cases. The judge merely announces that a certain approach will be taken, states the appropriate precedential authority, and then finds for the plaintiff or defendant. 38 The written decision is usually 33. D.M.A. Strachan, The Scope and Application of the But For Causal Test, 33 MOD. L. REV. 386, 389 (1970) (noting that the but for test of cause-in-fact attempts to be objectively scientific but, in fact, is subject to policy considerations). 34. John Borgo, Causal Paradigms in Tort Law, 8 J. LEGAL STUD. 419, 439 40 (1979) (arguing that causal determinations are not goal neutral but subject to the underlying policy considerations of the courts). 35. Fowler Harper and Fleming James, Jr. survey Calabresi s notion that cause-in-fact is actually designed to serve human goals and the inherently demonstrable flexibility of causal determinations reflects the operation of these goals. 4 FOWLER V. HARPER & FLEMING JAMES, JR., THE LAW OF TORTS 20.2 n.1, at 89 91 (2d ed. 1986). 36. Judith Jarvis Thomson, The Decline of Cause, 76 GEO. L.J. 137 (1987) (outlining that, because of the increasing demands of regulating new technological industries, causation is becoming increasingly blurry, and this phenomenon has aided plaintiffs during the past two decades). 37. For arguments regarding the importance of liability standards over causal policy, see in particular Richard Epstein, A Theory of Strict Liability, 2 J. LEGAL STUD. 151 (1973), in which he argues that the but for test is inaccurate, too philosophical, too reliant on hypotheticals, and too administratively costly. In its place, Epstein proposes a regime of strict liability where a party who harms another party is strictly liable for that harm. For alternative economic proposals of liability regimes which reduce the importance of cause-in-fact in traditional torts scenarios, see Steven Shavell, An Analysis of Causation and the Scope of Liability in the Law of Torts, 9 J. LEGAL STUD. 463 (1980) [hereinafter Shavell, An Analysis of Causation]; Steven Shavell, Uncertainty Over Causation and the Determination of Civil Liability, 28 J.L. & ECON. 587 (1985) [hereinafter Shavell, Uncertainty Over Causation], and WILLIAM M. LANDES & RICHARD A. POSNER, THE ECONOMIC STRUCTURE OF TORT LAW (1987) [hereinafter LANDES & POSNER, ECONOMIC STRUCTURE]. Shavell, Landes, and Posner posit that the use of more probabilistic, statistical evidence coupled with a furthered understanding of the ex post causal risks involved in a torts situation would lead to a simplification of the causation analysis in a negligence regime. 38. Examples abound of this judicial reluctance to explain the departure from traditional causal principles. Generally, once an alternative causal approach is first developed in the common law, its use as a future precedent is reduced to a nearly automatic application when a court deems its use necessary. In Audet (Guardian ad Litem of) v. Bates, [1998] 78 A.C.W.S.3d 406 (B.C.), available at 1998 A.C.W.S.J. Lexis 81941, the British Columbia Supreme Court adopted the inference approach as advocated in Snell v. Farrell, [1990] 72 D.L.R.4th 289 (B.C.). The case dealt with whether or not the pinching of a fetus s umbilical cord by a physician later caused brain

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 261 tacit on the subject of what pressed the judge first to adopt a modified rule of causation and second to find for the particular party. While there exist three distinct forms of adjusted causal doctrine to deal with ambiguous cause-in-fact cases, all three forms may not differ in actual effect on the outcome of the case. In fact, the only difference between reversing the burden of proof of causation and inferring causation or finding a material increase of risk of injury may be a semantic difference. Throughout the analysis of ambiguous cause-in-fact approaches, it will become apparent that no ambiguous cause-in-fact case cited in this study would have been decided any differently had any one of the three causal tools been utilized by the courts. Fact finders who reach for a modified causation test may be searching only for a method of rhetoric to find for the party that, for normative reasons, they believe should be successful in the action. 39 Judicially determined cause-in-fact exists not in absolutes but on continuums. The crucial difference, states Stephen Pincus, between the but for test[,]... on one hand, and the increased risk test, material contribution test or substantial factor test, on the other, is linguistic. 40 Courts that decide ambiguous causein-fact cases might appear unpredictable, unstable, and somewhat maverick. Their causal determinations do not seem fettered by the particular cause-in-fact approach they apply. 3. Theory Behind the Policy of Cause-in-Fact Competing traditional positivist and normative tort theories have long attempted to provide an explanation for why judges make causal determinations and, subsequently, how they should make causal determinations. These explanations may provide some insight into what policy considerations are behind a court s decision in ambiguous cause-in-fact cases. Traditionally, tort law has been seen as a legal regime designed to both compensate the injured and deter undesirable behavior. Acting as a rough and ready public insurance system, tort law provides a mechanism to redress the needs of a plaintiff who has suffered damages. At the same time, the fear of tort liability can act as a deterrent to curb potentially harmful social behavior. Cause-in-fact decisions could therefore turn on a fact finder s desire to compensate an apparently needy plaintiff or, alternatively, to deter egregious behavior on the part of the defendant. This insurance-deterrence duality has taken on significance by shaping two influential modern tort theories. damage to the child. The court inferred causation to the defendant physician in this ambiguous cause-in-fact case by merely stating that it was adopting the inference principle from Snell v. Farrell and inferring causation: In the absence of evidence from Dr. Bates consistent with the likelihood of a contrary cause, I am permitted to, and do, infer as fact that the artificial rupture of the membranes was the cause of the prolapse which eventually injured Teddy. The approach which I have followed in the determination of causation is that mandated by the Supreme Court of Canada in the case of Snell v. Farrell. Audet, [1998] 78 A.C.W.S.3d at 424. This lack of judicial reasoning and straightforward application of alternative cause-in-fact approaches is typical of most judgments concerning ambiguous cause-in-fact scenarios. 39. Such is the argument of Stephen Pincus, who posits that a linguistic analysis of causation cases demonstrates that the language chosen by the fact finder is nearly immaterial once traditional causal principles are abandoned. Stephen N. Pincus, Progress on the Causal Chain Gang: Some Approaches to Causation in Tort Law and Steps Toward a Linguistic Analysis, 24 OSGOODE HALL L.J. 961, 1010 11 (1986). 40. Id. at 994.

262 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 The corrective justice movement views as integral the moral significance in the relationship struck between an injured plaintiff and the wrongdoer defendant. 41 Causal judgments, under this theory, are made based on perceptions about a plaintiff s normative loss at the hands of the defendant. Fact finders are prompted to restore the moral balance between the injured plaintiff and negligent defendant. The insurance and deterrence functions of tort law should therefore be utilized to further the goal of redressing the moral wrongdoing of the defendant. The law and economics movement argues that tort law s goal is the efficient maximization of wealth. 42 Using money as a measure of worth, efficiency theory puts faith in the market and freedom of contract to check and counter rising accident and administrative costs of the torts system in attempting to strike the most efficient balance. The theory uses a rational actor model where players in the tort system behave rationally by being risk-neutral cost avoiders. Law and economics theorists are not concerned with the distribution of wealth, but rather the maximization of the total possible wealth in each torts transaction. To this end, legal economists believe that the structure of the insurance and deterrence effects of tort law should be aimed at promoting efficient behavior. Both corrective justice and efficiency theory will be used as positivist lenses to explain the development of new causal solutions utilized by courts. Afterward, each theory will be used in its normative sense to test the validity of a novel approach to ambiguous cause-infact cases. III. MODIFICATIONS TO TRADITIONAL CAUSE-IN-FACT DOCTRINE A. The Reversal Approach One method of resolving ambiguous cause-in-fact cases involves reversing the burden of proof of causation to the defendant to disprove causation. A plaintiff must first prove 41. See the work of corrective justice theorists Ernest J. Weinrib, Lewis N. Klar, and Richard Wright. For Weinrib s conception of corrective justice, see Ernest J. Weinrib, The Special Morality of Tort Law, 34 MCGILL L.J. 403 (1989) [hereinafter Weinrib, Special Morality]; Ernest J. Weinrib, Causation and Wrongdoing, 63 CHI.- KENT L. REV. 407 (1987); Ernest J. Weinrib, A Step Forward in Factual Causation, 38 MOD. L. REV. 518 (1975) [hereinafter Weinrib, A Step Forward]; TORT LAW: THE INTERNATIONAL LIBRARY OF ESSAYS IN LAW AND LEGAL THEORY (Ernest J. Weinrib ed., 1991). Weinrib references moral philosophy of the Greeks and Kant in forming his notion that tort law should be a system for redressing moral wrongs and making plaintiffs whole again. See generally Weinrib, Special Morality, supra. For Wright s conception of corrective justice, see Richard Wright, Actual Causation vs. Probabilistic Linkage: The Bane of Economic Analysis, 14 J. LEGAL STUD. 435 (1985) [hereinafter Wright, Actual Causation]; Richard Wright, The Efficiency Theory of Causation and Responsibility: Unscientific Formalism and False Semantics, 63 CHI.-KENT L. REV. 553 (1987) [hereinafter Wright, The Efficiency Theory]; Wright, Causation in Tort Law, supra note 1. Wright perceives corrective justice to be the maintenance of responsibility between a victim and a wrongdoer. He argues that no other system is as effective in performing this important role. Wright, Clarifying the Concepts, supra note 29, at 1004, 1076 77. Klar echoes Wright s notions of tort law enforcing responsibility and underscores Weinrib s insistence that moral philosophy is the unique underpinning driving the torts system. See Lewis N. Klar, The Role of Fault and Policy in Negligence Law, 35 ALTA. L. REV. 24, 29 31 (1996) [hereinafter Klar, Fault and Policy]. 42. For differing views of the law and economics conceptions of efficiency in causation, see the works of the legal economists Richard Epstein, Steven Shavell, William Landes, and Richard Posner, supra note 37. Shavell uses economic theory to argue that causation may be logically deduced to a relative economic certainty. Shavell, Uncertainty Over Causation, supra note 37, at 589. While this may be true on an ex post analysis, it is questionable how Shavell s economic variables could be discerned on an ex ante basis. Wright, Actual Causation, supra note 41, at 446. Therefore, the value of his efficiency model on a normative basis may be limited. Id. at 447. Similarly, Landes and Posner engage in an ex post causal risk analysis and, in turn, reduce the operation of causation as a determinative element of the negligence action. Id. at 454. For sharp criticism of Shavell, Landes, and Posner, as well as the entire efficiency movement, see Wright, The Efficiency Theory, supra note 41.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 263 that the defendant s conduct fell below the applicable standard of care. This breach of the standard of care must have increased the risk of the particular injury suffered by the plaintiff. If the defendant cannot prove that his negligence was not the cause of the plaintiff s injury, he is deemed to have caused the plaintiff s injury. This causal tactic appears to be used most often when a fact finder determines that a defendant will likely have more information about causation than would the plaintiff. Judge Learned Hand best captured the spirit of reversing the burden of proof to the defendant by stating: The single tortfeasor cannot be allowed to escape through the meshes of a logical net. He is a wrongdoer; let him unravel the casuitries resulting from his wrong. 43 1. The Genesis of the Reversal Approach The judicial history of this modification to the traditional but for test reveals some of the difficulties of resolving ambiguous causation cases solely in this fashion. Reversing the burden of proof to the defendant to disprove causation was first used in the United States and Canada in cases involving multiple defendants whose negligent actions came together to produce a single, indivisible harm. 44 The impossibility of sorting out which of the multiple defendants was solely responsible for the harm led courts to craft legal doctrine that aimed to accommodate for the perceived injustice of robbing a plaintiff of any chance of recovery through factors beyond the plaintiff s control. It was the collusion of negligent action that destroyed a plaintiff s ability to prove cause-in-fact. Furthermore, it was thought that the two negligent defendants were informationally better equipped to sort out who had the greater role in bringing about the injury. Imposing joint and several liability on the multiple defendants who were unable to disprove causation seemed to have an information-forcing effect, which prompted the defendants to sort out amongst themselves who would compensate the plaintiff. 45 The philosophical underpinnings of these multiple defendant cases were transformed into a possible solution to determining causality in ambiguous cause-in-fact cases. In McGhee v. National Coal Board, 46 Lord Wilberforce of the House of Lords appeared to reverse the burden of proof of causation to the defendant employer. The plaintiff employee could prove that the employer materially increased the risk of workplace injury by not providing shower facilities to allow workers to clean themselves; however, he could not prove that it was this negligence that caused his dermatitis. In the spirit of Cook v. Lewis 47 and Summers v. Tice, 48 Lord Wilberforce held that this material increase in risk of injury was enough to prompt a switch in the traditional burden of proving causation: And if one asks which of the parties, the workman or the employers, should suffer from this inherent evidential difficulty, the answer as a matter in policy and justice should be that it is the creator of the risk who, ex hypothesi must be 43. Navigazione Libera T.S.A. v. Newton Creek Towing Co., 98 F.2d 694, 697 (2d Cir. 1938). 44. Most prominent are the shooting cases. See, e.g., Summers v. Tice, 199 P.2d 1 (Cal. 1948); Cook v. Lewis, [1951] 1 S.C.R. 830. In fact, the earliest known reversal of the burden of proof of causation was a Mississippi Supreme Court case. See Oliver v. Miles, 110 So. 666 (Miss. 1927). This case had identical facts to Summers v. Tice and Cook v. Lewis, where two hunters negligently fired at one plaintiff. 45. Saul Levmore, Gomorrah to Ybarra and More: Overextraction and the Puzzle of Immoderate Group Liability, 81 VA. L. REV. 1561, 1562 (1995) (canvassing information-forcing effects that various liability regimes can have on negligent defendants who withhold information from plaintiffs). 46. [1973] 1 W.L.R. 1 (H.L. 1972). 47. [1951] 1 S.C.R. 830. 48. 199 P.2d 1 (Cal. 1948).

264 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 taken to have foreseen the possibility of damage, who [sic] should bear its consequences. 49 The McGhee case was subsequently used in Canada in five ambiguous cause-in-fact cases to switch the burden of proof of causation to a defendant. 50 Furthermore, the Supreme Court of Canada reversed the burden of proof of causation to the defendant manufacturer of substandard breast implants in Hollis v. Dow Corning. 51 Justice LaForest relied on Cook v. Lewis 52 to find in favor of the plaintiff. The manufacturer s negligence in failing to provide proper product risk information to physicians had seriously undermined 53 the plaintiff s power to prove that her defective breast implants were the cause of her serious health problems. In the United States, causal reversal was also used to sort out difficult ambiguous cause-in-fact cases. In Haft v. Lone Palm Hotel, 54 the defendant hotel owners had to disprove that their negligence in not providing lifeguards or proper signage at their pool did not cause the death of a father and young son. Here, the identifying characteristic of ambiguous cause-in-fact cases, absence of proof as to how the deaths were caused, prompted Justice Tobriner to determine that: [T]he shift of the burden of proof in the instant case may be said to rest on a policy judgment that when there is a substantial probability that a defendant s negligence was a cause of an accident, and when the defendant s negligence makes it impossible, as a practical matter, for plaintiff to prove proximate causation conclusively, it is more appropriate to hold the defendant liable than 49. McGhee, [1973] 1 W.L.R. at 6. 50. See Nowsco Well Servs. Ltd. v. Canadian Propane Gas and Oil Ltd., [1981] 7 Sask. R. 291 (Sask. C.A.) (A truck containing highly flammable contents spontaneously exploded while parked near an open flame. The burden of proof of causation was reversed to the truck driver, who failed to disprove causation.); Rivtow Equip. Ltd. v. W.J. Watt Constr. Ltd., [1989] 73 Sask. R. 161 (Sask. Q.B.) (A logging machine was mysteriously damaged by fire while left in the forest unattended. The burden of proof of causation was reversed to the machine operator, who failed to disprove causation.); Lomax v. Arsenault, [1986] 41 Sask. R. 227 (Sask. Q.B.) (A government agency diverted water from a private fish pond. An unusually cold winter froze the pond nearly to the bottom, and the fish stock perished. The question before the court was whether the reduction of the water in the pond caused the fish to die or whether the fish would have died in any event, with the water at the previous level. The burden of proof was reversed to the agency, who was able to prove that its negligence was not the cause of the death of the fish.); E. Kootenay Cmty. Coll. v. Nixon and Browning, [1985] 35 A.C.W.S.2d 29 (B.C.), available at 1985 A.C.W.S.J. Lexis 31069 (A variety of factors greatly slowed construction of a college building, causing an enormous and unprojected cost-overrun. The burden of proof of causation was reversed to the architects, who were unable to prove that their tardiness was not the cause-in-fact of the extra costs incurred for construction.); Letnik v. Toronto (City), [1988] 2 F.C. 399 (Fed. Ct.) (The captain of a ship negligently struck another moored ship in harbor. Two weeks later, the struck ship mysteriously sank while still moored in harbor. The court reversed the burden of proof to the negligent captain who was unable to disprove that striking the ship did not cause it to sink.). It is interesting to note that Canadian academic commentary suggests that Canadian courts post- McGhee regularly reversed the burden of proof of causation to the defendant in torts cases. In fact, that seems to be a misconception, perhaps created by the notoriety of the above five cases, which did reverse the burden of proof. It is hard to imagine that a causal tactic used in only five cases within a decade could be characterized as routine. For example, Mitchell McInnes states that, after McGhee, Canadian courts routinely reversed the burden of proof once a plaintiff established that a defendant had increased the risk of the injury that actually occurred. Mitchell McInnes, Causation in Tort Law: A Decade in the Supreme Court of Canada, 63 SASK. L. REV. 445, 447 (2000). Similarly, Allan M. Linden notes that the McGhee innovation was embraced in Canada. ALLAN M. LINDEN, CANADIAN TORT LAW 107 (6th ed. 1997). 51. [1995] 4 S.C.R. 634, 681 86. 52. [1951] 1 S.C.R. 830. 53. [1995] 4 S.C.R. at 683. 54. 478 P.2d 465 (Cal. 1970). Justice Tobriner relied on the reasoning in Summers v. Tice, 199 P.2d 1 (Cal. 1948), in reversing the burden of proof to the defendant.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 265 to deny an innocent plaintiff recovery, unless the defendant can prove that his negligence was not a cause of the injury. 55 Justice Tobriner relied on Ybarra v. Spanguard, 56 where the court used the doctrine of res ipsa loquitur to, in effect, reverse the burden of proof of causation (as well as all outstanding elements in the negligence action) to the defendant hospital, requiring it to disprove causation. 57 Like McGhee and Haft, evidence as to the precise cause was missing. Unlike McGhee and Haft, but similar to Hollis, the disappearance of the evidence of causation was a direct result of the defendant s negligent behavior. This important difference may have prompted a retraction in courts frequency of reversing the burden of proof of causation. The British House of Lords overruled the reversal concept of McGhee in Wilsher v. Essex Area Health Authority. 58 This case of medical negligence involved determining what caused a newborn baby to suffer blindness. The hospital was negligent in administering too much oxygen to the baby; however, the complicated birth or possible congenital defects could also have been a cause of the blindness. The evidence did not clearly point to one definitive cause. The House of Lords therefore sent the case back for a new trial in order to further examine the cause-in-fact issue. In demanding retrial of the case, the Lords indicated that McGhee laid down no new principle of law whatever 59 and that Lord Wilberforce s reversal idea was a minority opinion and not to be followed. This statement sent a signal to British courts to cease reversing the burden of proof in ambiguous cause-in-fact cases. The reverberation of the Wilsher decision was felt in Canada where the reversal idea was rejected by the Supreme Court of Canada in Snell v. Farrell. 60 Justice Sopinka called for an end to the use of McGhee as a precedent advocating reversal of the burden of proof of causation. Instead, Sopinka adopted the inference approach from Wilsher, hoping to retain the spirit of the flexible McGhee reversal approach without departing from traditional torts principles. Courts in both Canada and Britain now adopt either one of two modifications of cause-in-fact doctrine: the inference approach or the increased risk approach. In California, the reversal approach was rejected by the California Supreme Court in Rutherford v. Owens-Illinois, Inc. 61 The burden of proof for causation remains with the plaintiff in cases of cancer allegedly caused by asbestos. The differences between the Summers v. Tice situation involving multiple tortfeasors and a case involving exposure to 55. Haft v. Lone Palm Hotel, 478 P.2d 465, 476 n.19 (Cal. 1970). But see Smith v. Americania Motor Lodge, 113 Cal. Rptr. 771 (Cal. Ct. App. 1974), which qualified Haft v. Lone Palm Hotel, stating that reversing the burden of proof was only an option if the plaintiffs themselves were non-negligent. In Smith, also a drowning case like Haft, there was evidence tending to show that the children who drowned were themselves negligent in entering the pool, which had proper warning signs and may have been barricaded by a rope. The children were aged ten and eleven and were capable of reading. The court held that the children were negligent in ignoring printed warnings, crossing a barricade, and swimming in an unsupervised pool. Id. at 774. 56. 154 P.2d 687 (Cal. 1944). 57. In Part III.C, infra, this paper will outline the conceptual differences between cause-in-fact doctrine and using res ipsa loquitur to make determinations based on circumstantial evidence. 58. [1988] 1 A.C. 1074 (H.L.). The inference approach as advocated in Wilsher will be discussed below. See infra Part III.C. It is important to also note that the material increase to risk approach espoused by McGhee was recently reaffirmed by the House of Lords in Fairchild v. Glenhaven Funeral Servs. Ltd., [2002] 3 W.L.R. 89 (H.L.). Lord Rodger of Earlsferry wrote that Wilsher glossed over McGhee in a way that does not do justice to the reasoning about causation. Id. at 162. 59. [1988] 1 A.C. at 1090. 60. [1990] 2 S.C.R. 311. 61. 941 P.2d 1203 (Cal. 1997).

266 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 carcinogenic materials were highlighted by the court in determining that reversals of the burden of proof were not warranted in this type of a case. 62 The Restatement (Second) of Torts still maintains that the burden of proof of causation remains with the plaintiff. 63 2. Criticisms of the Reversal Approach However, no jurisdiction is without criticism of the reversal approach. There exists a fundamental problem in transferring causation doctrine from a multiple defendant-single possible cause of injury situation to a single defendant-multiple possible cause of injury situation. The shooting cases from which the reversal concept is derived involved fact patterns where the defendant s actual conduct deprived the plaintiff of any ability to prove cause. The reasoning behind the reversal lies in the belief that the negligent defendants had greater information about causality than the plaintiffs, who, by virtue of the defendants actions, had no information. In the majority of ambiguous cause-in-fact cases, though not all, proof of causation is not destroyed by the defendant s negligence but is merely absent. 64 Such was the case in McGhee where the defendant s negligent behavior did not negate the employee s ability to isolate the cause of his dermatitis. Such was also the case in Haft v. Lone Palm Hotel, where the lack of warning signs did not destroy the plaintiff s ability to determine why the drownings occurred. These cases go beyond the information forcing purpose of burden reversal and force the defendant to prove that his breach of duty was not the cause of the plaintiff s injury. 65 There is no informational disadvantage overcome by applying the reversal approach in these types of cases because neither side has any more causal information than the other. Therefore, it is questionable whether reversing the burden of proof to the defendant is any different than merely stating that the defendant is liable for causing the injury on a breach of the standard of care alone. Indeed, Fraser and Howarth believe that cases like McGhee use causal language to address liability concerns based on the defendant s breach of the duty of care. 66 If the plaintiff cannot prove causation because causal information does not exist anywhere, the defendant may be no more able to disprove causation. The reversal notion may therefore be acting as a disguise for a court wishing to find liability based solely on evidence of a breach of duty. The causation step is removed by asking the defendant to disprove something neither he nor anyone else could disprove. Richard Epstein is critical of the reversal modification of cause-in-fact doctrine. He states that: P [a plaintiff] must normally prove a case by a preponderance of evidence. If there is any question of negligence, then P gets to double dip when weak evidence of causation is piled on top of weak evidence of negligence. Even a rule that requires P to present the preponderance of evidence on negligence and causation separately could allow recovery when the chances that P s full case is 62. However, Joseph H. King, Jr. has advocated the use of the reversal approach for determining cause-infact in pre-existing injury cases. See Joseph H. King, Jr., Causation, Valuation, and Chance in Personal Injury Torts Involving Pre-existing Conditions and Future Consequences, 90 YALE L.J. 1353, 1394 (1981). 63. RESTATEMENT (SECOND) OF TORTS 433B(1) (1965) ( [T]he burden of proof that the tortious conduct of the defendant has caused the harm to the plaintiff is upon the plaintiff. ). 64. Weinrib notes that in McGhee, the opportunity to prove cause-in-fact was not impaired by the defendant s negligent behavior; rather, proof was absent. Weinrib, A Step Forward, supra note 41, at 526. 65. G.L. Fridman states that the McGhee case in particular goes beyond Cook v. Lewis, [1951] 1 S.C.R. 830, and forces the defendant to prove he did not cause the plaintiff s injury by his breach of duty. G.L. FRIDMAN, TORTS 329 30 (1990). 66. J.D. Fraser & D.R. Howarth, More Concern for Cause, 4 LEGAL STUD. 131, 141 42 (1984).

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 267 made out is only just over 25 percent, as when P wins barely by a 50-plus percent of each issue separately. It is risky to allow P to use a close victory on the issue of negligence or breach of statutory duty as presumptive evidence of causation. It is doubtful that any court would adopt this inference on questions of causation when raised in the context of contributory negligence, so why adhere to that rule here? 67 Even though Epstein challenges the logic of adherence to the reversal approach, the fact remains that courts in all three jurisdictions have occasionally reversed the burden of proof in ambiguous cause-in-fact cases. 68 Something is prompting them to cloak liability for substandard care in causal language, even when there can be no gain by forcing information from a defendant who has no more information than the plaintiff. When the negligent defendant in an ambiguous cause-in-fact case has an informational advantage over the plaintiff, reversing the burden of proof of causation may have the desired effect of forcing that information to come to the surface. Yet when causal evidence is not being withheld by the defendant but is merely absent for both parties, reversing the burden of proof has the effect of automatically holding the defendant liable for causing the injury. Courts appear to be giving the defendant a chance to exonerate herself while really holding the defendant liable for a breach of standard of care. In other words, it is a rhetorical tool available for courts to do what they want. 69 B. The Increased Risk Approach A second method for resolving ambiguous cause-in-fact cases centers around holding a negligent defendant liable for materially increasing the risk of injury to the plaintiff. This approach is like the reversal approach in that it is used primarily to compensate an injured plaintiff despite a lack of causal evidence. Unlike the reversal approach, it has an information-forcing effect on the defendant. Therefore, it is perhaps more suited to situations where neither plaintiff nor defendant can muster enough causal evidence to determine what exactly was the cause of the plaintiff s injury. The increased risk approach operates as follows: A plaintiff must first establish that the defendant breached the applicable standard of care. The plaintiff must tender some cause-in-fact evidence, but this evidence will not be enough to prove on a balance of probabilities that the defendant was the cause of the injury. Next, the plaintiff must establish that the defendant s breach of the duty of care materially increased the risk of the particular injury. The plaintiff must have been exposed to that risk and then suffered that particular injury. Despite the fact that the plaintiff cannot definitively link the negligent increase in risk with the exact cause of injury that she suffered, courts have held the defendant liable based on materially increasing the risk for that particular type of injury. 67. RICHARD A. EPSTEIN, TORTS 250 (1999). 68. Curiously, Gillian Demeyere posits that the McGhee reversal approach merely dresses the civil standard of proof rule as part of a substantive standard. This is akin to the concept that the choice of substantive law for solving causation problems may be linguistic in nature and not tied to any novel function of the law. See Gillian Demeyere, The Material Contribution Test: An Immaterial Contribution to Tort Law: A Comment on Briglio v. Faulkner, 34 U.B.C. L. REV. 317, 330 (2000). 69. With the absence of the causation step, the reversal approach s effect is almost akin to Epstein s regime of strict liability.

268 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 1. The Genesis of the Increased Risk Approach The present-day increased risk approach in Canada and Britain, like the reversal approach, seems to have grown out of a previously existing tort doctrine in Britain: the material contribution to injury doctrine. 70 In the United States, by contrast, ruminations of the increased risk approach appeared as early as 1885. 71 It is important to distinguish the contribution to injury doctrine from the contribution to risk of injury approach as both are separate and distinct legal tools that are used for different purposes. Courts have continually blurred the distinctions between the two, and this blurring has resulted in a confusing web of causal rhetoric in court judgments. a. The Increased Risk Increased Injury Dichotomy in Britain and Canada In Bonnington Castings v. Wardlaw, 72 the British House of Lords determined that a defendant employer was liable for the injury of its worker. The worker developed lung disease from the accumulation of noxious dust inhaled from two concurrent sources, one of which was the employer s work site. Although the dust created from the employer s workplace was not itself sufficient to have caused the lung condition suffered by the plaintiff, the total combination of dust from both sources, one negligent and one nonnegligent, was the cause of the lung disease. The House of Lords held that the employer, while not responsible for the sole cause of the injury, made a material contribution to the injury through its negligence and should be liable for its entirety. 73 In cases thereafter, a plaintiff bringing a torts suit could succeed if she could prove that the negligent defendant made a material contribution to her injury, even though the defendant was not the sole contributor to the cause of the injury. The McGhee v. National Coal Board 74 case transformed the material contribution to injury doctrine into a more murky form, confusing material contribution to the plaintiff s injury with material contribution to the risk of injury. In McGhee, the majority of the House of Lords broke with the lower appeals court and held that materially contributing to a plaintiff s injury was a mirror concept with materially contributing to the mere risk of a plaintiff suffering injury. 75 If a plaintiff could prove that a defendant s negligence materially contributed to the plaintiff s injury, the plaintiff could succeed. Yet Lord Wilberforce, whose judgment sparked the reversal approach, spoke solely of the 70. This test is synonymous with the substantial factor test in the United States. 71. See Reynolds v. Texas and Pac. Ry., 37 La. Ann. 694 (La. 1885), discussed in detail infra Part III.B.1.b. 72. [1956] 2 W.L.R. 615 (H.L.). 73. Id. at 620. 74. [1973] 1 W.L.R. 1 (H.L. 1972). 75. See id. at 8 for the speech of Lord Simon of Glaisdale, in particular, which attempted to synthesize the increased risk approach with the material contribution to injury test. But see Lord Reid: Nor can I accept the distinction drawn by the Lord Ordinary between materially increasing the risk that the disease will occur and making a material contribution to its occurrence. Id. at 5. Lord Salmon stated that [i]n the circumstances of the present case it seems to me unrealistic and contrary to ordinary common sense to hold that the negligence which materially increased the risk of injury did not materially contribute to causing the injury. Id. at 11 12. Furthermore, he stated: In the circumstances of the present case, the possibility of a distinction existing between (a) having materially increased the risk of contracting the disease, and (b) having materially contributed to causing the disease may no doubt be a fruitful source of interesting academic discussions between students of philosophy. Such a distinction is, however, far too unreal to be recognized by the common law. Id. at 12 13.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 269 defendant s negligence materially increasing the risk of injury to the plaintiff. Liability in Lord Wilberforce s speech was based on the defendant employer materially increasing the risk that the plaintiff employee would contract dermatitis. Because cause-in-fact was ambiguous, with two independent possible causes potentially responsible for the harm, Lord Wilberforce appeared to distinguish the contribution to injury approach, as espoused in Bonnington Castings, with a new causation approach based on proving material contribution to risk of injury. 76 The difference lay in the fact that in Bonnington Castings, the two causal forces were acting simultaneously and cumulatively, whereas in McGhee the causal forces were independent and exclusive of each other. Adding more dust pollution to already existing dust pollution contributes to the actual injury of the lung disease. There is no causal link missing here. The defendant may have increased the likelihood that the plaintiff would develop lung disease, but the cause of the lung disease is known: It is the exposure to dust. The defendant has merely added to the harm of the already existing injury. This type of case does not fit the pattern of ambiguous cause-in-fact cases. However, as in McGhee for example, causing dermatitis by denying employees washing facilities is an operative cause exclusive from causing dermatitis by some other unknown medical frailty in the plaintiff. The causes here are independently sufficient to have caused the harm. There is no cumulative effect. Thus, Lord Wilberforce held that the defendant employers materially increased the risk of the particular type of injury suffered by the plaintiff worker. 77 The worker was exposed to that risk and suffered that particular injury. Despite having an insufficient amount of evidence linking the defendant s negligence to the plaintiff s actual injury suffered, Lord Wilberforce found liability based on the defendant s negligent and material increase in risk of one of the possible causes of the injury. 78 Since McGhee, courts in Britain and Canada have adopted a variety of inconsistent interpretations of the concepts muddled by the House of Lords. Some courts have properly applied the material contribution to injury test, or substantial factor test, as an alternative to the but for test when faced with two or more simultaneous, successive, and cumulative causes. 79 However, because of the confusingly synonymous use of the words risk and injury, many courts have repeatedly used the material contribution to risk approach in deciding ambiguous cause-in-fact cases, while stating in the written judgment that they were using the material contribution to injury test. The result has been a chaotic body of law that loses the overall effect of the difference between the two causal doctrines. This difference is perhaps most clearly stated by Bruce Pardy: A material contribution [to injury] is not equivalent to a materially increased risk. A material contribution is part of the cause of the injury. An increased risk may not have caused any part of the injury, or may have partially contributed, or may have caused the entire injury by itself. 80 76. Id. at 6. 77. McGhee v. Nat l Coal Bd., [1973] 1 W.L.R. 1, 7 [H.L. 1972]. 78. Id. 79. See, e.g., Athey v. Leonati, [1996] 3 S.C.R. 458 (A plaintiff with pre-existing back condition was hurt in two successive car accidents.); Corey v. Havener, 65 N.E. 69 (Mass. 1902) (Two motorists sped up behind a horse and carriage, frightening the horse and causing it to bolt.); Arneil v. Paterson, [1931] 1 A.C. 560 (H.L.) (Two dogs owned by two different owners became loose and killed some sheep in a farmer s flock.). 80. Bruce Pardy, Risk, Cause and Toxic Torts: A Theory for a Standard of Proof, 10 ADVOC. Q. 277, 287 (1989).

270 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 The net effect of confusing the doctrines is that there is a muting of Lord Wilberforce s innovation of holding a defendant liable not for causing the injury but for causing the risk that an injury would develop. It may be far easier for a plaintiff in an ambiguous cause-infact case to prove cause-in-fact based on an increased risk of injury rather than to establish multiple, cumulative causes of the injury. The confusingly similar terminology has watered down the development of this alternative causal solution. Furthermore, it has become nearly impossible to determine when a court is using the increased risk approach because the judgment may state a defendant s liability is based on contribution to injury and not contribution to risk of injury, even though the increased risk approach is adopted implicitly. 81 The overt increased risk approach is, however, not without its active proponents in the judiciary. It has been applied in a variety of ambiguous cause-in-fact cases. 82 The Manitoba Court of Appeal recently held a physician to be the cause of a newborn baby s malformity. 83 The court found that the physician materially increased the risk of injury to the unborn child by negligently continuing to prescribe to the mother a drug harmful to developing fetuses. 84 The plaintiff patient could not definitively prove when the harm suffered by the developing child manifested itself and whether that manifestation coincided with the time she began taking the harmful drug prescribed by the physician. 85 The cause of the baby s malformation could have either been the drug or some other independent exclusive cause occurring either before or after the start of the prescription. The judge determined that, while the plaintiff could not link the defendant doctor s negligence with the actual cause of the malformity, the doctor s negligence materially increased the risk that that particular type of fetal malformity would occur. 86 That was enough to hold the doctor liable for the injury to the baby. Other Canadian cases continue to rely on the increased risk approach as espoused in McGhee, despite the recent movement toward the inference principle marked by the 1990 decision, Snell v. Farrell. 87 81. Courts in all three jurisdictions continually confuse the increased risk approach with the material contribution to injury, or substantial factor, test when assessing cause in ambiguous cause-in-fact cases. See, e.g., Swanson Estate v. Canada, [1991] 80 D.L.R.4th 741 (Fed. C.A.) (holding a government transportation agency to have materially contributed to the cause of the injury of the plaintiff when his plane crashed). The agency allowed the uninspected plane to take off, knowing that the plane was unsafe for air travel. Despite the holding, it appears that the agency really materially contributed to the risk of injury and not to the actual injury itself. Also note the confusing language in Evers v. Dollinger, 471 A.2d 405, 415 (N.J. 1984) (holding the defendant physician s failure to make a diagnosis and properly treat the patient increased the risk of recurrence or of distant spread of plaintiff s cancer, and that such increased risk was a substantial factor in producing the condition from which plaintiff currently suffers ). The judge here combined both the increased risk approach and substantial factor test in one sentence. 82. See, e.g., Chow (Litig. Guardian of) v. Wellesley Hosp., [1999] 86 A.C.W.S.3d 322 (Ont. Gen. Div.), available at 1999 A.C.W.S.J. Lexis 45318 (holding that physicians who ignored the warning signals of premature birth increased the risk of the baby being born with birth defects); Briffett v. Gander & Dist. Hosp. Bd., [1992] 103 Nfld. & P.E.I.R. 271 (Nfld. Tr. Div.), aff d, [1996] 137 Nfld. & P.E.I.R. 271 (Nfld. C.A.) (holding that leaving a man having a heart attack in the hospital emergency room hallway untreated and lying on a stretcher increased the risk that he would perish hours later, which he did); Hamil v. Bashline, 392 A.2d 1280 (Pa. 1978) (holding the failure to diagnose and treat signs of cancer to have increased risk of death by cancer). 83. Webster v. Chapman, [1997] 126 Man. R. 2d 13 (Man. C.A.). 84. Id. at 92 93. 85. Id. at 88 89. 86. Id. at 93. 87. [1990] 2 S.C.R. 311. For Canadian cases relying on McGhee s increased risk approach, see, e.g., Audet (Guardian ad Litem of) v. Bates, [1998] 78 A.C.W.S.3d 406 (B.C.), available at 1998 A.C.W.S.J. Lexis 81941 (holding that the physician s negligence in pinching a newborn s umbilical cord materially increased the risk of brain damage to the child); Stroud v. Gen. Hosp. Corp & Pollett, [1993] 110 Nfld. & P.E.I.R. 22 (Nfld. Tr. Div.) (holding that a hospital negligently allowing a patient to shave himself materially increased the risk that the patient would die of infection from shaving wounds); Doern v. Phillips Estate, [1995] 2 B.C.L.R.3d 349 (B.C.), aff d, [1997] 43 B.C.L.R.3d 53 (B.C.C.A.) (conducting a reckless police chase held to have materially increased the risk

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 271 The most resounding acceptance of the increased risk approach has come from the British House of Lords in 2002 in Fairchild v. Glenhaven Funeral Services Ltd. 88 The Lords exhaustive and comparative analysis of causation doctrines in a variety of international jurisdictions is bound to influence the further refinement of this difficult area of the law. While the five speeches that make up the decision are different in form, their thrust is common: A plaintiff can successfully prove cause-in-fact by proving the defendant materially increased the risk of injury and the plaintiff then suffered that particular injury. The case involved exposure to cancer-causing asbestos. Themes of risk exposure and difficulty in proving causation from a scientific standpoint permeated the speeches. It can be expected that this decision, which extensively cites cases from Canada and the United States, will reverberate throughout much of the common law world. b. The Increased Risk Approach in the United States In the United States, the genesis of the increased risk approach appears to have occurred much earlier than in Britain or Canada. In the 1885 case of Reynolds v. Texas and Pacific Railway, 89 a 250-pound woman was urged to hurry down unlit stairs leading to the defendant s railway ramp. She slipped and fell, causing injury to herself. She had to prove that it was the defendant s unlit stairs that was the cause of her fall, not her own carelessness. The court found for the plaintiff and held that where the negligence of the defendant greatly multiplies the chances of accident to the plaintiff, and is of a character naturally leading to its occurrence, the mere possibility that it might have happened without the negligence is not sufficient to break the chain of cause and effect between the negligence and the injury. 90 In other words, the defendant s negligence materially increased the risk that the plaintiff would fall down the stairs. Following Reynolds, U.S. courts did not apply the increased risk approach with any fervor until, coincidentally, after 1973 around the time of McGhee s release in Britain. The mid- to late eighties exhibits the greatest number of cases invoking an increased risk approach in both Canada and the United States. In Canada, this phenomenon is attributed to the introduction of McGhee as a causation precedent; in the United States it is unclear from where its popularity stemmed. One can conjecture, however, that the flurry of controversy and academic debate about Lord Wilberforce s McGhee innovation may perhaps have crept into American judicial thinking. 91 The result is a resurgence of the increased risk approach, particularly in the area of medical negligence. Physicians failures to treat and diagnose patients often became characterized in the pattern of ambiguous cause-in-fact cases. Two or more competing independent possible causes left courts stymied as to where to attribute cause. Applying the increased risk approach allowed a court the ability to compensate the plaintiff when the that the plaintiff would attempt to avoid the police and accidentally steer his automobile into another oncoming vehicle); Givskud v. Kavanaugh, [1994] 147 N.B.R.2d 1 (N.B. Tr. Div.) (failing to inspect crop seeds for disease held to be a material increase in the risk that many farm crops would be infected by the diseased seeds). 88. [2002] 3 W.L.R. 89 (H.L.). 89. 37 La. Ann. 694 (La. 1885). 90. Id. at 698. 91. See, e.g., ROBERT E. KEETON, LEGAL CAUSE IN THE LAW OF TORTS 9 10 (1963) (discussing his theory formulating the Risk Rule, which holds that a defendant should be held liable for the harm caused within the scope of risks created by his negligent behavior). Keeton s theory may have assisted in priming U.S. academia for the ensuing discussions surrounding the increased risk approach. See, e.g., Wright, Causation in Tort Law, supra note 1, at 1763 65; see generally Christopher H. Schroeder, Corrective Justice and Liability for Increasing Risks, 37 UCLA L. REV. 439 (1990) [hereinafter Schroeder, Liability for Increasing Risks].

272 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 evidence could not establish cause-in-fact under the but for or substantial factor tests. For example, in Evers v. Dollinger, 92 the defendant doctor s failure to properly diagnose and treat the plaintiff patient increased the risk of recurrence or of distant spread of plaintiff s cancer. 93 A malfunctioning electrocardiogram unit and the subsequent unavailability of the physician prompted the court in Hamil v. Bashline 94 to hold that this failure to properly diagnose and treat increased the risk of harm to the patient, who was suffering a heart attack at the time. One constant in American increased risk approach cases of medical negligence is that courts continually rely on the ambiguous language in the 1966 decision of Hicks v. United States. 95 The court there stated that if there was any substantial possibility of survival and the defendant has destroyed it, he is answerable. 96 Perhaps the Hicks language operates similarly to Lord Wilberforce s judgment in McGhee in that both are invoked when a court wishes to relax traditional cause-in-fact standards in order to allow a plaintiff to prove causation. This was the reasoning of the California Supreme Court in Rutherford v. Owens- Illinois, Inc. 97 in holding that exposure to carcinogenic asbestos was a substantial factor in increasing the risk of developing cancer. Because it was a near impossibility to prove whether or not the defendant s particular asbestos filaments actually caused the plaintiff s cancer, the plaintiff was required to prove only that the defendant s product increased the risk of developing cancer. 2. Criticisms of the Increased Risk Approach One difficulty with the increased risk approach stems from the fact that a court is finding a defendant liable for a plaintiff s injury by causing a risk that the plaintiff s injury might occur. The missing link between negligent behavior and causality is bridged by deeming an increased risk sufficient as proof of cause-in-fact when other causal evidence is unavailable. 98 Like the reversal approach, the increased risk approach injects a great deal of discretionary power in the judicial system. Indeed, Gerald Robertson argues that the increased risk approach favors the plaintiff in every single application. 99 Furthermore, he notes that the defendant will then always have the burden of disproving causation. Once it has been established that the defendant fell below the standard of care, Robertson states that a plaintiff then only has to prove the existence of an actual injury that could likely have resulted from the negligence of the defendant. If evidence of precise cause-in-fact is missing, as it is in most ambiguous cause-in-fact cases, the court will automatically determine the defendant to be the cause under the increased risk approach because it is obvious that the defendant s negligent behavior increased the risk of injury for the plaintiff. Every breach of the duty of care, by its very nature, materially increases the risk of injury to the plaintiff. This increase in risk, in turn, forces the defendant to disprove causation. 92. 471 A.2d 405 (N.J. 1984). See, e.g., Scafidi v. Seiler, 574 A.2d 398, 403 05 (1990) (citing Dollinger and a host of cases that examine whether or not the defendant s negligence increased the risk of harm to a plaintiff who was already suffering from some pre-existing condition). 93. Evers, 471 A.2d at 415. 94. 392 A.2d 1280 (1978). 95. 368 F.2d 626 (4th Cir. 1966). 96. Id. at 632. 97. 941 P.2d 1203 (Cal. 1997). 98. This is different than treating risk increase as an injury itself, a concept which will be discussed infra in Part III.B.3.b. 99. Gerald Robertson, Overcoming the Causation Hurdle in Informed Consent Cases: The Principle in McGhee v. N.C.B., 22 U.W. ONT. L. REV. 75 (1984).

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 273 When juxtaposed with the reversal approach, Robertson s analysis is enlightening in two aspects. First, it appears that both the reversal approach and the increased risk approach allow courts to modify traditional causal principles to benefit a plaintiff in ambiguous cause-in-fact cases. Most importantly, both approaches lead to a nearly automatic finding of liability on the part of the defendant. There appears to be no practical difference between reversing the burden of proof of causation to the defendant and saying the defendant caused the plaintiff s injury by materially increasing the risk of injury. The defendant cannot escape either presumption. Second, what Robertson s analysis fails to stress is the fact that the increased risk approach systematically documents a court s reasonings for causal determinations. A defendant s liability does not stem from just any increased risk; rather, the risk created must be of a type likely to cause the particular injury of the plaintiff. Furthermore, the plaintiff must have been sufficiently exposed to the risk. Unlike the reversal approach, a court must go through a series of logical steps to establish that the material increase of risk did indeed exist and does indeed make the plaintiff s resultant injury more likely to have occurred. Reversing the burden of proof of causation to the defendant in an ambiguous cause-in-fact case does not allow for this rationalization of parting from traditional tort principles. 100 Although the differences between both approaches may be in name only, with the increased risk approach a court is forced to turn its mind to whether or not there is a likely causal nexus between the defendant s negligent risk creation and the plaintiff s injury. 3. Alternatives to the Increased Risk Approach There exist two theoretical alternatives to the increased risk approach that have garnered some attention with torts scholars but have yet to be considered by courts. The first involves proving cause-in-fact through increased risk by using statistical probabilities, or probabilistic evidence. The second involves treating an increased risk of injury as a new kind of compensable injury in and of itself. Each is detailed here in order to indicate the theoretical framework surrounding the increased risk approach. a. Probabilistic Evidence, Efficiency, and Increased Risk Using statistical probabilities as an aid in cause-in-fact analysis seems like a tempting solution when dealing with ambiguous cause-in-fact cases. If no one party can definitively prove or disprove causation, why not reach for a numerical calculation of whether or not the plaintiff s particular injury is a probable result of the defendant s negligence? Normative efficiency theorists have argued for a more empirical approach to causal determinations which would involve utilizing probabilistic evidence to calculate trends in increases in risk of injury. 101 Positivist efficiency theorists argue that courts are already implicitly using probabilistic evidence in making causal determinations. 102 If the increase 100. However, as has been discussed, the reversal approach does seem to be more effective in situations where the defendant holds an informational advantage over the plaintiff in regards to causation. 101. See, e.g., Shavell, An Analysis of Causation, supra note 37; Shavell, Uncertainty Over Causation, supra note 37. See also the works of other scholars who are not associated with the law and economics school of thought: John G. Fleming, Probabilistic Causation in Tort Law, 68 CAN. BAR REV. 661 (1989); John G. Fleming, Probabilistic Causation in Tort Law: A Postscript, 70 CAN. BAR REV. 136 (1991) [hereinafter Fleming, Probabalistic Causation: A Postscript]; Wright, Clarifying the Concepts, supra note 29, at 1067 77. 102. See, e.g., William M. Landes & Richard A. Posner, Causation in Tort Law: An Economic Approach 12 J. LEGAL STUD. 109, 129 32 (1983) [hereinafter Landes & Posner, Causation in Tort Law].

274 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 is beyond a certain threshold, it may be seen to be more administratively efficient to hold the defendant liable than allow the defendant to continue to behave inefficiently. 103 This would create optimal incentives for minimizing risky behavior when it is efficient to do so. Probabilistic evidence of causal tendencies could help courts determine at what level the increased risk of injury is tolerable and at what level it should be sanctioned. For example, it may be theoretically possible to predict that not providing any washing facilities for workers in a brick kiln results in nine out of ten workers contracting dermatitis. The risk of those same workers developing dermatitis from other causal sources may be one in sixty. In that case, the owner of a brick kiln who fails to install washing facilities should be held liable for increasing the risk of injury to his workers if a worker contracts dermatitis. If, however, it can be determined that only one out of one thousand workers will contract dermatitis by not having washing facilities at work, it may not be efficient to hold the brick kiln owner liable because chances are the owner is not the probable cause of the injury. Courts and corrective justice theorists, in contrast, have resisted paying any attention to probabilistic causal determinations for a variety of reasons. 104 The reaction against the idea stems largely from the fact that statistical probabilities are only helpful in measuring the general trend of a cross-section of causal situations. Courts prefer to concentrate on the more immediate situation of a specific plaintiff, a specific injury, and a specific defendant. 105 Stating that a certain event causes a certain injury ninety-nine percent of the time does not assist a court in determining what happened in the situation before it. Courts limit themselves to only particularistic, ex post causal probabilities. 106 In other words, courts are concerned only with what happened, not what was likely to happen, or what would likely happen if the event repeated itself in the future. Both positivist and normative corrective justice theorists are concerned with the moral significance of the unique relationship between plaintiff and defendant. They also see the tort process as one which redresses the imbalance between a single plaintiff and defendant. Corrective justice theorists emphasize the particular facts at hand because the theory is not concerned with the general trends of harm but the moral ramifications of harm in specific circumstances. All toxic torts, for example, are not seen in the same way according to corrective justice theorists. A greater degree of callous recklessness necessitates a greater perception of wrongdoing which, in turn, warrants a greater reason to award compensation to the plaintiff to make him or her whole. Different plaintiffs have different moral relationships depending upon the tortious circumstances. Statistical probabilities do not assist in prescribing the accurate characterization of the moral significance in each individually unique tort. 103. See, e.g., Shavell, An Analysis of Causation, supra note 37, at 487 88; Landes & Posner, Causation in Tort Law, supra note 102, at 132 33; see Shavell, Uncertainty Over Causation, supra note 37 at 604 06. 104. See, e.g., Weinrib, Special Morality, supra note 41, at 404 06; Klar, Fault and Policy, supra note 41, at 40 41; Wright, Clarifying the Concepts, supra note 29, at 1054 66. 105. Interestingly, Glenn Shafer states that the only probabilities that can be taken to be causally related are empirically valid probabilities close to zero or one. Glenn Shafer, Causality and Responsibility, 22 CARDOZO L. REV. 1811, 1834 (2001). 106. Richard Wright describes four types of causal evidence available to courts. Particularistic evidence is evidence of a particular occasion that makes real some aspect of a possible causal generalization. Ex post causal probabilities are case-specific probabilities. Ex ante causal probabilities are abstract probabilities dealing with a certain class of happenings and are independent of particularistic evidence. Naked statistics are simple reports of accidental groupings, such as how many blue taxicabs and how many yellow taxicabs go through an intersection on average in a given day. Wright states that courts only take particularistic evidence and sometimes ex post causal probabilities into account when answering causal questions. Ex ante causal probabilities, while useful for causal prediction, do not help account for what happened in the case. Naked statistics, Wright notes, are useless. Wright, Clarifying the Concepts, supra note 29, at 1050 51.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 275 Yet, when a court reaches for the increased risk approach to determine ambiguous cause-in-fact scenarios, it is actually moving closer to the positivist efficiency model, which asserts that courts are implicitly using probabilistic causation. 107 Holding a defendant liable for cause-in-fact by stating he materially increased the risk of injury seems to be the same as stating he increased the probability that the plaintiff would suffer the injury. Because ambiguous cause-in-fact cases exhibit two independent competing causes, a court applying the increased risk approach is really looking to probabilities of what it thinks happened. Causal evidence is absent, and examining the risks created by the defendant moves the cause-in-fact analysis from one of past facts to one of likely conjectures. A court shifts from ex post causal probabilities of what specifically happened in this particular case to ex ante causal probabilities of what would generally happen in these types of cases. In doing so, the court compensates the plaintiff based on the likelihood that the defendant s negligence caused the plaintiff s injury. The rhetoric of the court parallels the application of probabilistic evidence without the court even knowing it is doing so. A deception is created, allowing the court to operate under the assumption that it is using only particularistic ex post causal probabilities. For example, a court says to a defendant, You, defendant, increased the risk that this injury occurred, and we find you liable for causing the injury. Implicit in that statement is the court s internal thought that you, defendant, increased the risk that this injury occurred, and we know that that increased risk can likely cause this type of injury; therefore, we find you liable for causing the injury. The increased risk approach is therefore a disguised version of using probabilistic thinking to make causal determinations when precise evidence of cause-in-fact is nonexistent. This approach should therefore be favorable to both positivist and normative efficiency theorists as it operates more closely to their model of basing liability on balancing increased risk of injury with efficient behavior. b. Increased Risk of Injury as a Compensable Injury A recent outgrowth of the academic movement toward using probabilistic evidence is the idea that causal analysis should be simplified by imposing liability for risk-based damages whenever a defendant is negligent. An increased risk would be treated as a new compensable injury for which a defendant would be liable. Exposure to risk of harm would be considered a harm itself. In its most basic form, the proposal works by using ex post and ex ante probabilistic evidence to award damages based on the proportion of risk created by the defendant. 108 The award would be discounted to the extent that the plaintiff s injury was likely caused by risk factors other than the defendant s negligence. 109 Proponents of 107. This debate over the utilization of increased risk as a mechanism for liability findings has recently been revived. Mark Geistfeld argues that, although the mere existence of factual uncertainty should not warrant the shifting of the burden of proof of causation, a plaintiff can adduce epidemiological proof which must identify an increase in risk sufficient to establish tortious conduct by the defendant. Mark Geistfeld, Scientific Uncertainty and Causation in Tort Law, 54 VAND. L. REV. 1011, 1015 (2001). In a response to Glenn Shafer s arguments, supra note 105, Melannie Leslie notes that the entire tort system is built to tolerate uncertainties. See Melannie B. Leslie, Liability for Increased Risk of Harm: A Lawyer s Response to Professor Shafer, 22 CARDOZO L. REV. 1835, 1836 37 (2001). The increased risk approach may be suitable for toxic tort and products liability cases but is not necessary for the everyday injury case. See id. at 1841 43. 108. See, e.g., Pardy, supra note 80. Wright, Clarifying the Concepts, supra note 29, at 1068; Schroeder, Liability for Increasing Risks, supra note 91, at 154 57; Christopher H. Schroeder, Corrective Justice, Liability for Risks, and Tort Law, 38 UCLA L. REV. 143, 159 (1990); Glenn Shafer, Causality and Responsibility, 22 CARDOZO L. REV. 1811, 1834 (2001). 109. Almost like the reductions for jurisdictions that have comparative negligence or contributory negligence.

276 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 this refinement of the increased risk approach argue that traditional causation doctrine is inefficient and should be dispensed with because it allows for only a bipolar, winner-takeall system. 110 Classifying risk exposure as injury would allow a court more latitude to award damages. Damages would be based on a continuum of risk and harm, not on an allor-nothing model, as it currently is. The result is an increased distribution of compensation. More plaintiffs would be compensated and more defendants found liable, but the damage awards would correspondingly be reduced as existing risk factors other than the defendant s negligence would discount the award. This method of proving cause-in-fact has received no attention from courts in any jurisdiction thus far. Critics of compensating plaintiffs based on risk exposure alone argue that the administrative costs of calculating this risk exposure are astronomically high. The idea may perhaps be workable in long-latency torts where there is prolonged exposure to risk and the damage awards are high. 111 However, in most everyday negligence cases, especially ambiguous cause-in-fact cases where causal evidence is lacking, the required probabilistic evidence is nearly impossible to obtain and would be expensive to calculate. The distribution effect created by holding defendants liable on a continuum of risk exposure would benefit more plaintiffs by spreading compensation more evenly across litigants, but the compensation would be less, perhaps even unsatisfactory for many who really were injured by the defendant s negligence but were also exposed to other potential risk factors. Their damage awards would be whittled away for the mere fact that they were unfortuitously proximate to another possible source of harm. The normative corrective justice goals of redressing the moral imbalance for wrongdoing may not be fully met under this new torts doctrine. Once a defendant has been proven to be negligent, he must automatically be liable for some amount of damages as cause is attributed proportionally to various risk factors. It does not matter whether the defendant actually caused the harm to the plaintiff. Rather, he is held liable because his behavior could have statistically been a potential cause. Curiously enough, this model may not be attractive for normative efficiency theorists as well. There exists a greater risk of over-deterrence and underdeterrence when every tort suit is at the mercy of probabilistic causal evidence. The effect on activity levels of players in the tort system may thus end up being anything but efficient. The loss of the traditional causal nexus between the defendant s negligence and the plaintiff s injury results in a regime where a breach of the standard of care is the touchstone of liability. Perhaps this regime may actually increase the risk of over-deterrence of any potentially risky behavior. 112 These criticisms of the risk as harm theory are magnified when one considers ambiguous cause-in-fact cases. Because causal evidence is missing, and because there exist two or more independent but sufficient possible causes, the net effect of the risk as harm theory seems to be a splitting of the difference approach to causal situations. Rather than choosing one independent possible cause over another, a court would statistically split the difference between the two causes, effectively canceling out compensation for the plaintiff. This approach is a backward step to what was the catalyst for the departure from traditional causal principles in ambiguous cause-in-fact cases: a court s desire to pursue plaintiffsensitive normative considerations through cause-in-fact determinations. 110. See Schroeder, Liability for Increasing Risks, supra note 91, at 470 71. 111. See Kenneth W. Simons, Corrective Justice and Liability for Risk Creation: A Comment, 38 UCLA L. REV. 113, 114 (1990). 112. Many efficiency theorists are concerned with shaping causal rules so as to avoid over-deterrence of socially valuable behavior. See, e.g., Shavell, An Analysis of Causation, supra note 37, at 484; Shavell, Uncertainty Over Causation, supra note 37, at 588.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 277 C. The Inference Approach The third and final approach to resolving ambiguous cause-in-fact cases involves a court inferring causation based on a reasonable assumption of the facts of the case. Of all three approaches, this is the most discretionary and unpredictable. When faced with an ambiguous cause-in-fact case, a court may choose to infer causation on the part of the defendant when direct causal evidence is lacking but when a court feels there is a strong likelihood that the defendant s negligence was the cause of the plaintiff s injury. 1. Res Ipsa Loquitur and the Inference Approach The inference approach, while operating in a sometimes markedly similar fashion to the doctrine of res ipsa loquitur, is used for a completely different causal scenario: the ambiguous cause-in-fact case. Res ipsa loquitur allows a court to make reasonable inferences of negligence based on circumstantial evidence so that the mere fact that an accident occurred becomes evidence of liability. 113 Those inferences may include inferences of cause-in-fact. The application of res ipsa loquitur requires that three factors be present in the fact situation for an inference of negligence to be made. First, the plaintiff must prove that the event that caused the plaintiff s injury was one that ordinarily does not occur in the absence of negligence. Second, the plaintiff must prove that the instrumentality of harm was under the complete control of the defendant, in order to link the harm with the defendant s negligence alone. And third, the plaintiff must prove that the cause of the accident was unknown and not due to any voluntary action or contribution on the part of the plaintiff. Plaintiffs attempting to utilize res ipsa loquitur are not required to prove that the defendant s negligence was the sole possible explanation for their injury. 114 They must, however, show that the possibility of the defendant s negligence as cause-infact of the injury outweighs the possibilities of the other potential causes being the causein-fact. Res ipsa loquitur, however, is never applicable to an ambiguous cause-in-fact case. Ambiguous cause-in-fact cases, by their very nature, never exhibit the first and most important of the three factors necessary for an inference based on circumstantial evidence. The reason lies in the fact that ambiguous cause-in-fact cases are those where there are two independently sufficient possible causes at work, one of which involves the negligence of the defendant and one of which is the result of some other factor. Therefore, an equally likely possibility exists that the harm may have been caused by an event other than the defendant s negligence. Multiple sufficient causal explanations in ambiguous cause-in-fact cases defeat the purpose of evaluating circumstantial evidence with res ipsa loquitur because neither potential cause outweighs the other in terms of likelihood of the cause being the actual cause-in-fact. Furthermore, the inference approach requires at least some evidence demonstrating that the defendant s negligence could be a potential cause of the plaintiff s injury. That evidence may not be solely circumstantial in nature. Res ipsa loquitur is designed to assist a plaintiff in proving a case where no evidence of any possible cause can be found beyond merely circumstantial evidence. 113. The concept originated in the British decision Byrne v. Boadle, 159 Eng. Rep. 299 (Ex. Ch. 1863), where a sack of flour fell from a bakery window onto an unsuspecting plaintiff below the window. The court held that sacks of flour do not usually fall from windows without the assistance of negligent behavior. Id. at 301. Therefore, despite the fact that the plaintiff had no evidence that any member of the bakery negligently threw the sack out the window, the mere fact that the accident happened was sufficient to hold the bakery liable for the injury. Id. 114. See, e.g., McGonigal v. Gearhart Indus. Inc., 788 F.2d 321 (5th Cir. 1986).

278 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 Courts have refused to apply res ipsa loquitur in cases where there exists more than one causal explanation that does not allude to the defendant s negligence. For example, in Walston v. Lambersten, 115 two crab fishermen set out in their boat and never returned. The appellant s family argued for the use of res ipsa loquitur in establishing the cause of the disappearance. They asserted that the boat may have sunk due to the weight of the ship s catch. Both the District Court and the Court of Appeals refused to use res ipsa loquitur because the sea itself contains many hazards, and an inference of liability of the shipowner for the mysterious loss of his vessel should not be lightly drawn. 116 In particular, the court cited the notion that the boat could have struck one of the many water-soaked logs floating in those particular waters. 117 The Supreme Court of Canada has made a complete retreat from res ipsa loquitur, abolishing the doctrine in Fontaine v. Loewen Estate. 118 Two hunters were found dead inside their badly damaged truck, which had sunk to the bottom of a river bed. The defendant hunter s body was found behind the steering wheel with his seatbelt still in place. It was established that the area in which the hunters were driving experienced very heavy rain and gusting winds at about the time the truck went off the road. 119 It was also determined that the vehicle was speeding. Justice Major held that this circumstantial evidence did not support an inference of negligence. 120 Furthermore, he called for an end to the use of res ipsa loquitur in Canada, stating that circumstantial evidence should be weighed during the process of evaluating direct evidence. 121 The inference approach to ambiguous cause-in-fact cases is therefore designed to operate akin to res ipsa loquitur, but only in causal situations where the doctrine does not apply. 122 In some cases, like Ybarra v. Spanguard, 123 creative applications of res ipsa loquitur do appear to have the same effect as the reversal and inference approaches in holding the negligence of a defendant to be a cause-in-fact of the plaintiff s injuries. Unlike res ipsa loquitur, the inference approach may be applied in situations where there is one or more equally sufficient and non-negligent possible causes of the plaintiff s injury. The approach is obviously not restricted by the second res ipsa loquitur condition, as the alternate cause of the injury will not be one under the defendant s exclusive control. 2. The Genesis of the Inference Approach Most ambiguous cause-in-fact cases are resolved using the inference approach, which has supplanted the reversal approach and increased risk approach in the last few decades. In Britain, McGhee v. National Coal Board 124 was overruled by Wilsher v. Essex Area Health Authority, 125 putting an end to the reversal approach and curbing adherence to the increased risk approach. Wilsher was the ambiguous cause-in-fact case that involved multiple independently sufficient possible causes of blindness to a newborn child. It could 115. 349 F.2d 660 (9th Cir. 1965). 116. Id. at 662. 117. Id. at 662 n.1. 118. [1998] 1 S.C.R. 424. 119. Id. at 427. 120. Id. at 437. 121. Id. at 435. 122. Allan Linden notes that the inferential reasoning in the inference approach of Snell v. Farrell, [1990] 2 S.C.R. 311, is not dissimilar to res ipsa loquitur analysis. ALLAN M. LINDEN, CANADIAN TORT LAW 108 (6th ed. 1997). 123. 154 P.2d 687 (Cal. 1944). 124. [1973] 1 W.L.R. 1 (H.L. 1972). 125. [1988] 2 W.L.R. 557 (H.L.).

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 279 not be determined on the evidence whether or not the baby s blindness had been caused by hospital negligence in providing too much oxygen to the infant during the mother s labor. In that case, the House of Lords held that Lord Wilberforce s opinion in McGhee laid down no new principle of law whatsoever 126 and was to be considered as a minority opinion. The Lords read the remaining speeches in McGhee as not advocating a reversal of the burden of proof of causation to the defendant, but rather as inferring causation based on common sense. Lord Bridge in Wilsher noted that McGhee adopted a robust and pragmatic approach to the undisputed primary facts of the case 127 and ordered that there should be a retrial of the causation issue. After Wilsher, British and Canadian courts ceased using both the reversal and increased risk approaches advocated in McGhee. The Supreme Court of Canada echoed Wilsher s dismissal of McGhee two years later in Snell v. Farrell 128 and adopted the inference approach as the standard causal principle to be used in Canada. In Snell, an elderly patient s blindness could have been caused by either a negligent surgical operation or a conglomeration of health problems unrelated to the operation. Sufficient evidence proving on a balance of probabilities either the surgery or the health problems as cause-infact did not exist. The Supreme Court, led by Justice Sopinka, rejected the reversal approach, 129 adopting Lord Bridge s words from Wilsher. Courts were to use traditional causation principles in a common sense fashion: Very little affirmative evidence 130 adduced by the plaintiff could allow a court to take a robust and pragmatic approach 131 to the facts and make a common sense inference of causation. The addition of the House of Lords decision in Fairchild v. Glenhaven Funeral Services 132 may, however, decrease reliance on the inference approach in Canada and Britain. The speeches of Lord Bingham of Cornhill, Lord Hoffman, and Lord Rodger of Earlsferry emphasized the utility of the increased risk approach. Lord Rodger went so far as to note that, in an ambiguous cause-in-fact case like McGhee, it is something of a fiction to bridge the evidential gap with an inference. 133 Only the speech of Lord Hutton reasoned that the McGhee case stood for the principle that an inference could be drawn that a defendant s breach of the duty of care was the cause of a plaintiff s injury. 134 Thus, at 126. Id. at 569. Lord Bridge stated: On the contrary, it affirmed the principle that the onus of proving causation lies on the pursuer or plaintiff. Adopting a robust and pragmatic approach to the undisputed primary facts of the case, the majority concluded that it was a legitimate inference of fact that the defenders negligence had materially contributed to the pursuer s injury. The decision, in my opinion, is of no greater significance than that and to attempt to extract from it some esoteric principle which in some way modifies, as a matter of law, the nature of the burden of proof of causation which a plaintiff or pursuer must discharge once he has established a relevant breach of duty is a fruitless one. Id. He also said that Lord Wilberforce s reasoning must be regarded as expressing a minority opinion. Id. at 567. 127. Id. at 569. 128. [1990] 2 S.C.R. 311. 129. Id. Justice Sopinka stated: If I were convinced that defendants who have a substantial connection to the injury were escaping liability because plaintiffs cannot prove causation under currently applied principles, I would not hesitate to adopt one of these alternatives. In my opinion, however, the principles relating to causation are adequate to the task. Id. at 326 27. 130. Id. at 328. 131. Id. at 330. 132. [2002] 3 W.L.R. 89 (H.L.). 133. Id. at 163. 134. Id. at 143 44.

280 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 least in Britain, the inference approach may potentially be supplanted by the increased risk approach in certain kinds of cases. In the United States, there has been no marked preference of the inference approach over the other two approaches to ambiguous cause-in-fact cases. Rather, U.S. courts appear to be more flexible in adopting one of the three approaches. The inference approach has, for example, been utilized when plaintiffs suffer an injury as a result of the defendant s negligence and then mysteriously develop another medical condition at the anatomical site of the injury. It is nearly impossible to prove whether or not the negligence which resulted in the first injury caused the development of the subsequent condition. In Kramer Service v. Wilkings, 135 the plaintiff s scalp was badly cut from glass falling from a negligently repaired door overhang in a hotel. The wound did not heal, and the plaintiff developed skin cancer at the wound site. Conflicting expert medical evidence prompted the court to infer that the negligent disrepair of the defendant s hotel doorway was the cause-in-fact of the cancer. In Daly v. Bergstedt, 136 a woman fell in an unmarked wet aisle in a grocery store. She injured the left side of her chest and later developed breast cancer at the same site of injury. The court inferred that the cause-in-fact of the cancer was the grocery store s negligence in not warning its customers of the hazard of falling in the aisles. Inferences of cause-in-fact have also been considered in ambiguous cause-in-fact cases when a plaintiff with a heart condition fell down stairs in disrepair, 137 when a plaintiff is found dead at an unmarked open elevator shaft, 138 or when a train lacking rear lights was blamed as the cause of death of a young plaintiff found adjacent to railway tracks. 139 In one case, the inference approach was notably utilized to determine the cause of typhoid fever when a city worker negligently mixed the unsanitary fire department water supply with the drinking water supply and local residents simultaneously faced an outbreak of typhoid fever. 140 Perhaps the most famous example of the inference approach in the United States is the bug-bite case, Gallick v. Baltimore & O.R.R. 141 A railroad company allowed a stagnant pool of water to remain near the train tracks where employees regularly worked. The pool held such unsavory things as dead and decaying rats and pigeons. The stench attracted insects that would become diseased from the rotting material and would fly about the tracks. The plaintiff was standing near this pool and was severely bitten on the leg by an insect. He suffered a serious infection at the site of injury. There was no definitive evidence as to where the insect came from, although it likely flew from the pool. The Supreme Court held that it did not matter whether or not there were other possible competing causal explanations for the bug s origin since it was satisfactory to allow a jury to infer causation if it so wished. 3. Criticisms of the Inference Approach It appears that the inference approach is used by all three jurisdictions when a court does not know what happened to cause a plaintiff s injury, but has a strong sense that the defendant s negligent behavior must have been the cause. The problem with the approach is that it is completely up to the court to characterize the inference as it sees fit. There 135. 186 So. 625 (Miss. 1939). 136. 126 N.W.2d 242 (Minn. 1964). 137. Ingersoll v. Liberty Bank of Buffalo, 14 N.E.2d 828 (N.Y. 1938). 138. McCoy v. Quadrangle Dev. Corp., 470 A.2d 1256 (D.C. 1983). 139. Puckhaber v. S. Pac. Ry. Co., 64 P. 480 (Cal. 1901). 140. Stubbs v. City of Rochester, 124 N.E. 137 (N.Y. 1919). There were at least nine competing potential causes for the typhoid fever, one of which was the negligent mixing of water supplies. Id. at 138. 141. 372 U.S. 108 (1963).

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 281 exists no objective guidelines as to how or when to infer causation. The only guidelines are, as Justice Sopinka in Snell v. Farrell puts it, to use common sense. 142 In many instances, this may be an acceptable way to proceed if a court s common sense is somehow objective and shared with most people. 143 There are some ambiguous cause-in-fact cases that exhibit fact patterns that seem to beg a court to hold the defendant s negligence is the cause-in-fact of the plaintiff s injury. Even though causal evidence is lacking, it appears obvious that the defendant s negligence must have had a causal role. For example, there are ambiguous cause-in-fact cases in both the United States and Canada involving construction workers smoking on the rooftop of the plaintiff s building while repairing the roof with flammable roofing tar. 144 After the workers leave, the building mysteriously burns down. The courts held the defendants liable for the fire, even though there was no definitive proof of the cause-in-fact of the fire. Few would dispute a court s reasoning here in inferring causation. Yet, if the same workers were not smoking but eating peanuts, inferring causation based on their behavior becomes more questionable. 145 Thus, the inference approach is heavily dependent upon the way the evidence paints the negligent behavior of the defendants. If the evidence points to a rather innocent causal connection, like eating peanuts, rationalizing an inference of causation becomes difficult. Yet if the evidence points to a more wrongful causal connection, like smoking cigarettes on a roof covered in flammable roofing tar, it seems more likely that a defendant could and should be held to be the cause of the accident. The defendant should have known better. The inference approach, therefore, operates in a similar fashion to the reversal approach. Indeed, many scholars argue that the two are identical in practical effect. 146 Reversing the burden of proof of causation to the defendant results in the defendant s being liable for causation on the part of the defendant. This is the same result as inferring causation to the defendant in the face of insufficient evidence that does not establish the defendant s negligence as a prima facie cause-in-fact. Both approaches provide a wide latitude for the exercise of judicial discretion. Both are also quite unpredictable at times. Unlike the increased risk approach, there is little opportunity for a court to enter into detailed reasoning behind holding a defendant liable for cause-in-fact through a nontraditional application of causal principles. In ambiguous cause-in-fact cases, inferring causation may be problematic because the lack of articulated reasoning behind the departure from traditional cause-in-fact tests reduces the precedential value of a written court decision. No guidance is given for future courts facing these difficult cases because each inferred causal finding turns solely on the court s characterization of the particular evidence at hand. Normative efficiency goals may be most difficult to pursue with the 142. [1990] 2 S.C.R. 311, 317. 143. Lord Hoffman in Fairchild raises this exact point in the context of an analysis of ambiguous cause-infact cases like Snell v. Farrell, stating that there is sometimes a tendency to appeal to common sense in order to avoid having to explain one s reasons. Fairchild v. Glenhaven Funeral Servs. Ltd., [2002] 3 W.L.R. 89, 124 (H.L.). Lord Rodger of Earlsferry also distanced himself from Justice Sopinka in Snell v. Farrell s inference concept because the entire case was about the fact that the medical expert witnesses themselves would not make the inference which the court, in turn, did. Id. at 163. 144. See, e.g., Emery v. Tilo Roofing Co., 185 A. 409 (N.H. 1937); 378096 Ontario Ltd. v. Bond s Décor Ltd., [1998] 78 A.C.W.S.3d 1249 (Ont. C.A.), available at 1998 A.C.W.S.J. LEXIS 82735 (upholding [1995] 56 A.C.W.S.3d 227 (Ont. Gen. Div.), available at 1995 A.C.W.S.J. LEXIS 49944). 145. For further explanation of this example, see JOHN W. WADE ET AL., PROSSER, WADE AND SCHWARTZ S CASES AND MATERIALS ON TORTS 261 (9th ed. 1994). 146. See, e.g., FLEMING, THE LAW OF TORTS, supra note 1, at 227; Fleming, Probabalistic Causation: A Postscript, supra note 101, at 139; KLAR, TORT LAW, supra note 16, at 327 28; ALLAN M. LINDEN, CANADIAN TORT LAW 107 08 (6th ed. 1997).

282 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 inference approach because of the inherent lack of objective empiricism. A positivist efficiency explanation of causation is also elusive when courts utilize the inference approach without explaining the reasoning behind their findings. 147 The goal of efficiency in judicial lawmaking must, therefore, be inferred by the result. Efficiency theorists cannot point to any written evidence of a court furthering efficiency by departing from traditional causation doctrine. If a court were able to choose the most efficient party for whom to infer causation, the inference approach would allow the freedom to distribute in order to foster wealth maximization. But the approach itself offers no assistance in determining which party should bear the liability for cause-in-fact. It is more of a license to allow a court to deem cause where it sees fit. There is no guarantee that the most efficient result is, or will be, reached. Therefore, although the inference approach mirrors the reversal approach in its overall reduction of the burden of proof of causation for the plaintiff, the inference approach is captive to the same unpredictable deference to policy goals operating beneath the surface of the torts system. Courts are using the approach to do what they want. 148 IV. A NEW APPROACH TO AMBIGUOUS CAUSE-IN-FACT CASES The three judicially created modifications to traditional cause-in-fact doctrine allow a greater degree of flexibility in dealing with ambiguous cause-in-fact cases. A judge can reach for one of the three approaches to adjust the causal doctrine to compensate for a lack of causal evidence. As has been shown, use of an approach most often coincides with favoring the plaintiff s position, whether the underlying normative purpose is for wealth maximization or for restoring moral responsibility. The unique nature of ambiguous causein-fact cases demands a relaxed approach to traditional but for and substantial factor tests because, without any modifications, plaintiffs will continually lose these cases. However, each of the three current approaches exhibits some flaws. They can be prone to unpredictability and inefficiency while being completely captive to unarticulated judicial discretion. The advantages of plaintiffs persuading courts to use one of the three approaches are obscured due to the complexity and volatility of the historical application of the approaches to ambiguous cause-in-fact cases. Furthermore, common law precedents cannot develop in a meaningful way as the coherence of this body of law is haphazard at best. What is needed is a more structured and practical methodology for dealing with the unique nature of ambiguous cause-in-fact cases. This methodology should incorporate the beneficial qualities of all three approaches while avoiding potential shortcomings. It should also keep at the forefront the redressing of the evidentiary imbalance that is unique to ambiguous cause-in-fact cases. Finally, it should retain the flexibility at the heart of the three approaches, which would give courts freedom to pursue normative goals without the expense of predictability 149 and efficiency. 147. Although, of course, a positivist explanation of a causation decision would explain that the court seeks to achieve the most efficient result whether or not it articulates what it is doing. 148. Hence, by silence, courts play into the hands of both efficiency and corrective justice theorists in a positivist sense. 149. It is, of course, trite to argue that predictability is a valued asset in any development of substantive law. In this particular framework of the law of cause-in-fact, both efficiency theorists and corrective justice theorists may agree that predictability is valued. From a behavioral adjustment aspect (whether that adjustment is for a moral nature or a movement to greater efficiency), predictability is a bedrock in the common law. Not only are the parties in a tort suit affected by the presence or absence of predictability, but so too are all the players in the tort system. The importance of predictability from an insurance underwriting perspective cannot be overlooked.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 283 A. Structured Causation Where the but for and substantial factor tests fail in ambiguous cause-in-fact cases, a fresh causal doctrine unfettered by previous precedent may assist plaintiffs who cannot prove cause-in-fact on traditional grounds but nevertheless prove cause-in-fact in a structured manner. This new approach, called structured causation, 150 could operate as follows. A court must first determine that the case before it fits the pattern of an ambiguous cause-in-fact case. There must exist at least two independent possible causes sufficient to have caused the plaintiff s injury. Next, the plaintiff must be able to prove on a balance of probabilities that the defendant did breach the applicable standard of care. There must be some tangible evidence that links the defendant s negligent behavior with a possible cause of the injury. This evidence would not be sufficient to prove cause-in-fact on a balance of probabilities, but it would be enough to suggest some causal relationship. B. Reversing the Burden of Proof of Causation to Force Information If a court can determine that the negligent defendant is in an informationally advantageous position to the plaintiff, the court should order the burden of causation to be reversed to the defendant in order to force the information from the negligent defendant. This would be most obvious in cases where it can be discerned that the defendant s withholding of information robbed the plaintiff of an opportunity to prove cause-in-fact. Also, where it is clear that the defendant knew or should have known that his information, if available to the plaintiff, could have avoided the injury, the burden of proof of causation should be reversed to the defendant. These situations would most often arise in cases involving manufacturers of products or physicians and hospital staff. It could also operate in cases where the possible evidence for causation was destroyed as a result of the defendant s negligent action. 151 The court must be able to have some certainty that the reversal of the burden of proof should rightly force some information from the defendant. Even if there exists no information to be gleaned from this process, the fact that the defendant s behavior robbed the plaintiff of the opportunity for proof should prompt the reversal. 150. The term constructive causation was first coined by Mitchell McInnes, who noted that the tendency of Canadian courts to adjust causal doctrine may lead to a complete overhaul of the concept of cause-in-fact. Mitchell McInnes, Causation in Tort Law: A Decade in the Supreme Court of Canada, 63 SASK. L. REV. 445, 456 57 (2000). This author, while grateful to Professor McInnes for suggesting the notion of constructive causation as far back as 1997, prefers the term structured causation to signify the added elements of a logical sequence to the analysis, as discussed below. Constructive causation appears to candidly admit that there may be some fudging going on in applying the substantive law of causation to the facts at hand. This is what will hopefully be avoided in the application of structured causation. 151. As was the case in Nuttall v. City of Thunder Bay, [2001] 17 M.P.L.R.3d 290 (Ont. Super. Ct.), aff d, [2002] 115 A.C.W.S.3d 503 (Ont. C.A.), available at 2002 A.C.W.S.J. LEXIS 5576, where the inference approach was used to infer causation, based on Snell v. Farrell. Here, a city negligently allowed a city sidewalk to fall into disrepair, then tore up the very sidewalk section after the plaintiff commenced her slip and fall lawsuit but before she had a chance to test the sidewalk surface. Id. at 290. A reversal of the burden of proof of causation in this case, after the plaintiff adduced enough evidence to connect her fall with the possibility of the negligently maintained sidewalk, would perhaps have functioned to force the city to disclose its own records and tests of the sidewalk surface, which it refused to produce at trial.

284 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 C. Materially Increasing the Risk of Injury as Proof of Cause-in-Fact If a court cannot determine that the negligent defendant s withholding of causal information has robbed the plaintiff of proof of causation, the court should adopt a version of the increased risk approach. A court should hold the negligent defendant responsible for cause-in-fact if the plaintiff can fully prove the following: (1) there is a problem with evidentiary proof of causation because there exist two independent, equally sufficient possible causes of the injury; (2) the defendant breached the applicable standard of care; (3) there is some evidence that points to the defendant s breach of the standard of care as a possible cause of the injury, but clearly not enough to prove causation on a balance of probabilities; (4) the defendant s breach caused a material increase in the risk of a particular type of injury; (5) the plaintiff was exposed to that risk; and (6) the plaintiff suffered that particular type of injury. If the above six items can be proven by the plaintiff, the court should hold that the defendant caused the plaintiff s injury. 152 In essence, this approach asks: Is one of the more-likely-than-not causes the increased risk behavior of the defendant? A court should be forever mindful to fully articulate its reasons why the plaintiff was able to prove the six elements of structured causation. Note that this new approach does not treat risk as a compensable harm but only restricts itself to deeming that an already negligent defendant caused a plaintiff s injury by materially increasing the risk of that particular injury. The defendant s negligence does not have to contribute to the actual injury, but must contribute to the risk that the injury would have occurred. This flexible and structured causation doctrine should better serve all parties in a tort suit by adopting a more predictable, contextual methodology for dealing with ambiguous cause-in-fact cases. Most importantly, structured causation is workable in the British, American, and Canadian jurisdictions because it can logically be enmeshed with the way the common law has developed around ambiguous cause-in-fact cases. V. EVALUATING STRUCTURED CAUSATION A. Structured Causation Compatible with Corrective Justice View Structured causation actually reifies the operation of the tort system as seen through a corrective justice framework. Corrective justice surmises that the tort system redresses the imbalance created when one party causes harm to the other party. 153 Not only is the injured plaintiff made whole again, insofar as money damages can do, but the negligent defendant is punished for his wrongdoing by being forced to restore the plaintiff. This implicit 152. Fairchild v. Glenhaven Funeral Servs. Ltd., [2002] 3 W.L.R. 89. The causation tests developed by Lord Hoffman, Lord Bingham of Cornhill, and Lord Rodger of Earlsferry somewhat parallel the test for structured causation. The integral element of each of the Lord s proposed tests is the adoption of the increased risk approach, inclusive of the prevalence of the six above-mentioned factors. Id. at 170 71. 153. See Weinrib, Special Morality, supra note 41, at 409 10.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 285 morality in the tort system centers around the intimate relationship between the defendant and the plaintiff. Therefore, causation for corrective justice theorists is perhaps the most vital component of the torts action. A defendant must have caused injury to the plaintiff in order to be held morally responsible. In addition, a plaintiff must have suffered harm at the hands of the defendant in order to be compensated. Corrective justice theorists are at odds with efficiency theorists about the role that cause-in-fact plays in a tort suit. Cause cannot be placed on a statistical continuum but must either be present or absent. Furthermore, exposure to risk is not seen as a loss; there must be a factual and normative loss suffered by the plaintiff. 154 It is for these reasons that both normative and positivist corrective justice theorists are against using probabilistic evidence and mere risk creation for determining cause-in-fact. Positivist corrective justice theorists surmise that the departure from traditional torts principles in ambiguous cause-in-fact cases stems from a court s desire to award damages based predominantly on the perceived morality of the defendant s negligent conduct. When a plaintiff is denied compensation under traditional but for or substantial factor cause-in-fact analysis, a court may still redress the imbalance between the plaintiff and defendant by opting for one of the three alternative approaches to cause-in-fact. The addition of structured causation in ambiguous cause-in-fact cases only strengthens the theory that, when there is a perceived moral wrong in a tort suit, courts reach for a substantive law tool to right that wrong. Structured causation is merely a more refined tool that is more workable in difficult causation situations. Most important, structured causation does not depart from the common law but merely builds on it. The adoption of structured causation would be a natural outgrowth of acknowledging that courts adopt a more flexible tool in difficult causation cases. From a normative standpoint, the formal use of structured causation would give courts a method for redressing the moral imbalance in tort suits where the negligence of the defendant will go unpunished and a plaintiff uncompensated merely because the causal evidence does not reach beyond a balance of probabilities. Using structured causation, a court could make explicit its moral undercurrents by offering a more lucid explanation of why it is deciding a certain case a certain way. The stages of a structured causation analysis allow a court to consider the moral and ethical significance of important elements in the causation analysis. The first step to structured causation, reversing the burden of proof when there is a perceived informational advantage for the defendant, guides a court in attributing moral significance to the hiding of information. For keeping information from the plaintiff, a defendant is punished through a reversal of the burden of proof of cause-in-fact. If no informational advantage is perceived in the case, the court would then adopt the second stage of structured causation and assess the defendant s material contribution to the risk of injury. Because the causal test stresses the relative amount of risk created, the negligent behavior involved, the proximity and exposure to the wrongdoing, and the link between the actual injury suffered and the risk of that actual injury, the test comes closer than any of the three approaches to preserving the restorative nature corrective justice theory believes is in the tort system. Incorporating the material contribution to risk of injury component in the second stage of the structured causation analysis does not, on its face, increase a defendant s chances of being punished for behavior which does not have any moral blameworthiness attached. In ambiguous cause-in-fact cases, at least one possible and plausible causal 154. Id. at 408.

286 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 scenario must potentially be caused by the defendant s negligence. By tying the defendant s proven breach of the duty of care to the increase of the particularized risk that could have caused the plaintiff s injury, all the while in the face of some but not quite enough causal evidence, the defendant is, at the very least, held accountable for the breach of the duty of care. As corrective justice theorist Ernest Weinrib reassures, the law prefers a 50 per cent. chance of doing justice to a certainty of doing injustice. 155 By not applying structured causation in ambiguous cause-in-fact cases, the certainty of injustice exists because a defendant who breached the standard of care and contributed to the global risk factors associated with the plaintiff s injury escapes being held accountable for that behavior. Therefore, if the normative goal of the tort system is indeed to restore a plaintiff to moral wholeness, structured causation comes closest to structuring causal analysis around a frank acknowledgement of pursuing that goal while holding a defendant liable in suitable ambiguous cause-in-fact cases. B. Structured Causation Compatible with Efficiency Theory View Structured causation also helps further concerns of both positivist and normative efficiency theorists by streamlining the causal analysis in ambiguous cause-in-fact cases to allow for more predictable, and perhaps more efficient, judicial decisions. In this regard, the causation step in the tort regime is not minimized for the sake of efficiency, as many legal economists argue it should be. 156 Rather, it is expanded with some added limits on judicial discretion that do not exist in the present three approaches to ambiguous cause-infact cases. As mentioned above in the corrective justice evaluation of structured causation, it is important to remember that the introduction of structured causation in any jurisdiction does not require a restructuring of any common law concepts. There are cases in all three jurisdictions that espouse various versions of structured causation in using the inference approach, the material increase in risk approach, or the reversal approach. Any legal authority mentioned in this article can easily be used as a precedent for the adoption of structured causation. Structured causation merely orders the often implicit reasoning in the courts by demanding explicit answers to fundamental causal questions in ambiguous causein-fact scenarios. Therefore, the adoption of structured causation in no way alters the positivist view of the law operating to achieve efficient results. The addition of structured causation will, in fact, add to the efficiency. Normatively, if the goal of the legal system is to strive for efficiency, structured causation is an important step in the right direction for a key reason: Ambiguous cause-infact cases are undoubtedly the most administratively costly cases to process through the tort system. They require the most evidence, the most court time, the greatest use of expert witnesses, and their uncertainty allows for no easy answers throughout the causal analysis. As a result, the conflicting case law that has developed around ambiguous cause-in-fact cases, with its often tacit and discretionary causal reasoning, is adding to the inefficiency of the system. 155. Weinrib, A Step Forward, supra note 41, at 524. 156. See, e.g., Shavell, An Analysis of Causation, supra note 37; Shavell, Uncertainty Over Causation, supra note 37, at 484; LANDES & POSNER, ECONOMIC STRUCTURE, supra note 37. For criticisms of normative efficiency analysis of cause-in-fact, see John Borgo, Causal Paradigms in Tort Law, 8 J. LEGAL STUD. 419, 453 55 (1979) and Weinrib, Special Morality, supra note 41, at 407 08.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 287 A cost-effective adjustment to the system at the stage where lack of precedential guidance allows for inefficiency is therefore an attractive prescription. The first step in structured causation, that of deciding whether or not to reverse the burden of proof of causation to the defendant, fits with the economic motive behind information forcing. The party who can provide causal information at the least cost will bear the burden of producing that information. If it is the plaintiff, the plaintiff bears the burden of proving causation. If the defendant is withholding information and can more cost-effectively provide it to the plaintiff, the burden of proving causation will shift to the defendant. This informationforcing effect reduces administrative costs of gathering and interpreting causal information by shifting those costs to the party who is most able to defray the expense. 157 The second step in structured causation, that of assessing whether or not a defendant s negligence materially increased the risk of injury to the plaintiff, should also further the goals of efficiency. Because a defendant s negligent behavior will most often be deemed to have increased the risk of injury to the plaintiff, structured causation acts akin to a regime of strict liability. This is an acceptable way to structure the liability regime because the costs of discovering potentially absent causal information are so high in ambiguous causein-fact cases. If a defendant s negligent behavior indeed pushes these costs high enough to make causal information more costly to provide than it would be to merely compensate the plaintiff outright, then holding the defendant liable for materially increasing the risk of injury to the plaintiff appropriately regulates activity levels of the defendant. A defendant will be deterred from acting in a risky manner that would bring about an ambiguous causein-fact situation. 158 In most ambiguous cause-in-fact cases where neither defendant nor plaintiff has destroyed the means of causal proof, but where the defendant s behavior has created the increased risk of injury, the defendant is usually the least cost avoider who should rightly be held liable for the negligence. It is the defendant s care level that matters and a liability rule mirroring strict liability would help to minimize accident costs by reducing the incentives for a defendant to engage in risky behavior where the costs of gathering and interpreting causal information outweigh the costs of compensating the plaintiff. Furthermore, this approach also provides an insurance effect to the plaintiff, funded by the defendant, who has the greatest control over the risk of harm. Structured causation is also somewhat compatible with the notion of creating ex ante incentives for wealth maximization. Unlike the three current approaches to ambiguous cause-in-fact cases, the increased predictability of structured causation could act as a catalyst for a more structured incentive system. The reversal, increased risk, and inference approaches allow generous amounts of judicial discretion to creep into a court s analysis. A court s plaintiff-sensitive policy goals are not articulated in written judgments. But the doctrinal framework of structured causation forces a court to account for why it is making a causal judgment in a certain way. Efficiency considerations regarding the relative cost of providing causal information are incorporated into the design of structured causation. Therefore, administrative costs can be evaluated more completely through the step-by-step analysis of the relationship between increased risk and injury contained in the second part of structured causation. The party most able to bear the costs of the injury is more likely to be found liable if a court can assess the informational elements and the risk elements of each respective party. 157. The advantages of information forcing in sculpting liability rules is a cornerstone of the law and economics movement. Recently, the design of mechanisms for information forcing has received much attention. For an ideal example of how information forcing in the design of torts liability regimes operates, see, for example, Levmore, supra note 45, at 1562 63. 158. See Shavell, An Analysis of Causation, supra note 37, at 476 77.

288 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 Ambiguous cause-in-fact cases can be resolved under structured causation by accounting for both the ex ante and ex post considerations about causality, alleviating the criticisms leveled by corrective justice theorists that efficiency theory restricts itself to an inadequate ex post causal analysis only. The ex ante concerns are dealt with in the first prong of the test where informational advantages are assessed. The second prong of the test combines a detailed analysis of what did happen to increase risk of injury with the flexibility to determine what most likely would have happened had this accident repeated itself in the future. The but for and substantial factor tests do not incorporate this forward-looking opportunity but are restricted only to ex ante thinking. Curiously enough, the addition of structured causation would not result in overdeterrence of useful behavior. First, rarity of occurrence of ambiguous cause-in-fact cases in the tort system would restrict the use of structured causation to only those difficult causal scenarios where there exist two independent, equally sufficient causal explanations. Second, the fact that structured causation requires initial proof that the defendant breached the standard of care, followed by at least some evidence tying cause-in-fact to that breach, increases the chances that the defendant is indeed liable for the accident. Finally, requiring proof that the defendant s behavior increased the risk of one of the global risk factors that possibly could have caused the plaintiff s injury, and the plaintiff was exposed to that risk, ultimately poses an efficiency question of the bearing of the cost burden of the accident. In its final practical effect, structured causation is akin to Shavell s concept of reducing the importance of causal analysis in favor of the duty of care analysis. 159 By semantically focusing on the cause-in-fact stage, the question really becomes one of risk allocation based on an established breach of the duty of care. The efficient answer to the cause-in-fact question may, ironically, follow the comment of corrective justice theorist Weinrib, stated above, that the law prefers a fifty-percent chance of achieving efficiency than a certainty of behaving inefficiently. The greatest efficiency lies in the increased predictability of the outcomes of ambiguous cause-in-fact cases when structured causation is applied. Potential defendants can adjust not only care levels but activity levels well before a tort suit, thereby avoiding this costly administrative step. There would be deterrence of actions that are likely to destroy causal proof or add to the global risk factors of injuries to others. Insurance underwriters can better evaluate risks in difficult causal scenarios by evaluating the inherent riskiness in insuring a defendant whose behavior may regularly involve him or her in an ambiguous cause-in-fact situation. And, of course, lawyers and judges would have a practical tool to assess the outcomes of potentially difficult and almost always high-stakes ambiguous cause-in-fact tort suits. Structured causation therefore furthers normative efficiency goals by providing a doctrine which can be tailored to foster maximum allocation of available wealth. VI. CONCLUSION By using structured causation, courts in the United States, Britain, and Canada can begin to develop a cohesive and context-sensitive approach to ambiguous cause-in-fact cases. The three judicial modifications to traditional cause-in-fact doctrine can be consolidated into one workable approach. This approach eliminates many of the theoretical and practical flaws of each approach while still allowing courts to determine cause in ambiguous cause-in-fact cases, which is the fundamental purpose behind modifying causein-fact principles in the first place. Structured causation can coexist with the two major 159. Id. at 482.

2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 289 positivist accounts of the tort system. It functions equally well in a system that is operating efficiently or is restoring balances between citizens. Structured causation also furthers the normative goals of the major theoretical frameworks of tort law. The new methodology is better tailored to promote efficiency or to redress moral imbalances. Structured causation can assist courts in determining cause-in-fact in ambiguous cases where two or more independently sufficient possible causes exist. Because one of those possible causes is the negligence of a defendant, a court must balance the desire to compensate the injured plaintiff with the cautionary recognition that the negligent defendant may not in fact be the actual cause of the injury. Structured causation thus equips courts to more competently answer the dreaded causal question of what happened?

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