Lecture October 8, 2003 On fertility

Transcription

1 Lecture October 8, 2003 On fertility 1. Secular trends 1.1. Preamble Just as mortality levels embarked on a long and gradual decline, so did fertility levels. The onset of fertility decline in Western and Northern Europe can be dated to about 1870 on average. There is an exception, France, where fertility levels began to tumble as early as 1790 in some rural areas. In contrast, in developing countries, fertility levels began to come down only after 1960 in a few countries and only after 1975 in most countries. There are some laggards and most but not all are in the African subcontinent. A few are spread throughout the Muslim world. But not al Muslim countries have high fertility. While there is some heterogeneity, there is also some important common features. And the most impressive and perhaps most puzzling is that TFR are all pointing to near replacement levels, that is with a value slightly below or above 2.00 Figure 1: From United Nations Below Replacement Fertility Just as longevity made us pause and consider what are the forces that drive it, so is this descent into replacement of fertility. And as in the case of mortality, where we found puzzling from an evolutionary point of view the existence of very high life expectancies, in the case of low levels of fertility we wonder: what does it mean for our species to live with replacement levels of fertility for a sustained period of time? 1.2. Our agenda (PPP) Text from PPP 2.A few facts: initial levels of fertility -For long periods of time the rate of increase of the human population was close to 0, say in the neighborhood of Since life expectancy was such that the probability of surviving up to age was not more than , it follows that the following expression holds approximately (the expression assumes that the population was stable, that is, that fertility and mortality were constant): exp(r*ag)= GRR*.50 where r is the rate of natural increase, Ag is the mean length of a generation and GRR is the gross reproduction rate. If we assume that Ag is approximately equal to the mean age of childbearing, say 27, then we can solve for GRR=2.62 Assuming that there are 1.05 male births for every female birth it follows that the TFR must have been of the order of 5.4 or slightly over. -In Western Europe there was enormous diversity but, according to Hajnal, it could be summarized as follows:

2 -Western and Northern Europe had nuclear families, late marriage and relatively low TFR (of the order of ). We are now at levels of TFR that are below 2 -Eastern Europe had extended families, early and universal marriage and relatively high TFR (above 5.5). Their current TFR are also below 2 (The line dividing Eastern and Western Europe is an imaginary line traveling North from Trieste in North-Eastern Italy up to San Petersburg in Russia) Map of Europe in PP presentation -In US, Australia and N. Zealand, TFR falls from levels around 6.0. Current levels around In Latin America, prior to the fertility decline around 1970, most countries had TFR of the order of 6-7. This number has been reduced to something around A few exceptions are : Argentina, Uruguay with TFR never exceeding 4.5 and with very early fertility decline and current values around In China the TFR drops beginning around 1960 from values over 6 to current values below In Bangladesh, TFR drops sharply during the 80 s from very high levels (exceeding 6.5 to levels right around 3.0) -In Africa there is evidence of strong fertility decline only in a few countries, including Nigeria, Kenya, Zimbabwe and Bostwana but also Senegal and Ghana. - An important inference from the aforementioned data is that in both cases, for developed and developing countries, mortality decline occurs before fertility changes. Fertility decline in most cases follows with a lag the fall of mortality. This implies that the rates of natural increase must increase for a period of time which will be longer the longer the lag is, as shown in Figure 1 Figure 2 from Cohen in PP presentation -The period during which fertility falls from relatively high to low levels (including parts of the period prior to when fertility begin to decline and during which mortality is already falling) is called the demographic transition. Corresponding to it there is a demographic transition theory. 3.The tail-end of fertility decline Post-transitional fertility levels (and patterns) are fairly homogeneous. Just as countries are converging toward high life expectancies, so they are converging toward low levels of fertility. They have done so in different ways but it all appears inevitable Figure 3 on timing distribution of countries that started fertility decline Figure 4 on projected fertility levels Figure 5 on difference between projected and observed levels Figure 6 on the probabilities of staying at low levels

3 This homogeneity is maddening. And while the same homogeneity takes place in mortality, there is something more puzzling here. After all, we all would like to survive longer and we wish others would do so as well, but in fertility, why should all of us want to have no more than what is necessary for replacement? 4.Task: How can we understand fertility levels and changes? 4.1A framework Just as in the case of mortality, we can formulate a simple model of determinants of fertility by paying attention to proximate factors that affect it. In the case of mortality, these were Exposure, Resistance and Recovery. Before we undertake the task of formulating intermediate factors, we need to introduce an important distinction between supply of surviving children and demand of surviving children. Supply: refers to the number of children surviving (say up to age 15) that couples are expected to have if they do not intentionally control or limit reproduction Demand: refers to the number of children surviving (say up to age 15) that couples would desire to have, even though they may be unaware of it (when they are unaware of their demand we refer to it as the latent demand). Supply and demand may differ or they may be equal. In some cases people may want to have more children surviving than what the can actually have (for example because of excess infant mortality that cannot be compensated for by higher fertility). In other cases they may demand less than the supply mainly because they cannot or they do not know how to limit the supply. We will later speak of the costs of fertility control but for the time being we only need to clarify what we mean by demand and supply of children i. The supply of children. The supply is equal to the total number of children a couple could have without interfering with the reproductive process (NF) times the probability of surviving to age 15 (S(15). We have chosen age 15 because this marks the age at which some children begin to enter into the labor force. And parents may desire children to increase revenues by having them enter into the labor force. But if work can start earlier, then an age lower than 15 should be used. Or, if parents want children as insurance later in life (when parents retire), that is, as social security, then an older age should be used. In other words the age at which we calculate the probability of surviving for children, S(x), depends on the nature of the desire for children among parents: in some cases it is a desire to use children s labor force, in others as old age security, in others as insurance against risks, and in yet others as objects of emotional gratification. In all cases the relation between supply of children and mortality is as in Figure 3 where we display supply versus the levels of life expectancy. Each curve corresponds to a particular level of supply of children BORN (NF). Variation within a curve reflects changes in mortality affecting S(15). Figure on supply of children from PP presentation

4 i.1 The factors that affect NF can be classified as follows: oooexposure to intercourse: Age at menarche(amr) Age at menopause(ame) affected by nutritional status affected by nutritional status Fraction of (Ame-Amr) spent within unions (f) determined by marriage rules oooopostpartum infecundability oooowaiting time to conception Affected by breast-feeding Affected by nutritional status Affected by frequency of intercourse (Spousal separation, taboos) Affected by presence of STD s oooointrauterine mortality Affected by maternal health status i.2 According to observed data we can calculate the ranges for TFR that would obtain if we choose extreme values (observed) for the quantities above. We use the following expression: TFR= f *( Ame-Amr ) / (Li+Lc+Lm) where f is the total fraction of the time lived between Ame and Amr spent in a marital union; Li is the waiting time due to post-partum infecundability; Lc is the waiting time for a conception and, Lm is the waiting time associated with fetal deaths. The range of values for the other components is as follows (in years) Waiting time due to post partum infecundability Waiting time to conception Waiting time due to fetal losses Li~ years Lc~ years Lm~ years The variation in TFR induced by these quantities is displayed in Figure 4 i.3.a simple formalization The above suggests that, in any society and any point in time, one can calculate the deviation from a max fertility value and assign to each of these components a contribution to the deviation. The formalization is simple:

5 TFR=TF*Cm*Ci*Cc*Ca This is called the Intermediate framework of fertility (Davis and Blake and Bongaarts) In this expression, TFR is observed fertility rate, TF is maximum fertility possible. Cm is the inhibiting effects of marriage, Ci the inhibiting effects of post partum infecudability, Cc the inhibiting effects of contraception and Ca the inhibiting effects of fetal mortality. Each of the C s varies from 0 to 1: when their value is close to 1 the corresponding factor does little to inhibit fertility. When the factor is close to 0, the factor is very efficient Important remark: distinction between MAX fertility and Natural fertility Maximum fertility is the level of fertility one would observe if there were none of the factors identified above (postpartum infecudability, marriage, etc ) had any suppressing effects. This is a purely theoretical construct. It is estimated to be around 15 Natural fertility is a concept coined by Louis Henry and refers to a fertility regime where there is no parity dependent birth control; that is there is no deliberate control of fertility level as a function of achieved number of children How much do these factors explain observed fertility? ==for high fertility populations (TFR>6) levels of marriage not always high but timing is not always early Cm~.78 levels of postpartum infecundability are typically high (breastfeeding); Ci~.65 levels of contraception is low; Cc~.910 levels of fetal death varies but is somewhat unimportant; Ca~.90 Predicted fertility~ 6.2 ==For low fertility populations (TFR<3) levels of marriage are moderate and timing late Cm~.55 levels of postpartum infecundability are typically low (breastfeeding); Ci~.93 levels of contraception is high; Cc~.30 levels of fetal death varies but is somewhat important(abortion); Ca~.88 Predicted TFR~ 2.0 Changes in marriage pattern in modern societies has quite a bit of influence on low levels of fertility; but it does so only because there is willingness to control fertility within a union See charts in PP presentation ii. Factors that influence demand for children It is important to make a distinction between latent demand and manifest demand. People may not know that they demand a certain number of children though in practice they do. Thus, for example, those who to the question: how many children do you desire? respond by saying: it is up to god, may have a latent demand though it goes unrecognized.

6 A second clarifying point is that in some societies the demand for children is something that goes together with a demand for timing of childbearing: what is important is not just HOW MANY but also WHEN? And how should they be spaced? What factors are the most important one for fixing the demand for children? Children are sources of benefits. And these can be material or pure emotional satisfaction. The material benefits accruing from children are of several types: labor, security in old age, protection for parents in a military sense, a means to establish social network connections, a means to realize parental aspirations for social accession. {{Example of highly paid women who withdraw from the labor force to care for children}} Children have a price tag (a cost) associated with them. These costs can be direct and are associated with the food, clothing etc as well as others such as education in modern societies. The costs of children are, of course, relative to the social and economic conditions of individuals and societies. Because the way we perceive our roles is different today than it was in say XVIII c Italy, the costs of children are equally different. Nobody would have thought then important to save money to send the eldest son to the University of Bologna that had just opened. There are also hidden, indirect costs as well and these are the ones associated with what you have to give up in order to have children. These are called opportunity costs. A typical opportunity cost is the one on which one blames low fertility of today: woman are traditional caretakers and the most important opportunity costs are those associated with giving up a graduate education, a job, a salary for one or more children. Since men earn more than women do, the opportunity costs if males exchanged roles with females for child care would be even larger Other opportunity costs that I think are paramount in today s transition to low fertility have to do with individual aspirations associated with status and with expenditures that confers status. This is not a reference to purely hedonistic consumption (although there is something of it) but also to expenditures that individuals go through to guarantee that next generations can move up the ladder: these take the form of investments in education but also in sports and all sorts of areas where children could be thought to have a chance to excel. Hedonistic pursuit are important as well and they surely account for a fair share of childless couples today. Children do indeed get in the way of accumulating for acquisition of goods that If one reasoned coldly, the number of children demanded would be a straightforward function of expected costs and benefits. Errors one way or the other would the product of chance and perhaps changing circumstances that were not accounted for in the calculus of costs and benefits. A summary of different social systems in terms of costs and benefits of children: Costs Benefits Traditional societies low (no education; high : labor; social security Care from others) networks Low opportunity costs Modern Societies High (education;sports no labor; no need Clothing; etc for social security

7 High opportunity costs Benefit only if they succeed iii. Factors that influence the costs of fertility regulation In a perfect world, supply and demand would adjust to each other; but there are some hidden costs we need to include. These are associated with fertility control: if one has a particular set of preferences for children and if to realize them you must reduce the gap between manifest demand and supply, you need to decide to control reproduction. And this may be a bottle neck since people may encounter all sorts of barriers, material and emotional, that could diminish their ability to limit fertility. Graph of effective demand for children (See PPP) To account for costs, let us assume that we create a measure to proxy the cost of fertility regulation; let us call it c; when c is 1, the cost is large and effective demand equals manifest demand. When c=1 cost of regulation plays no role and the manifest demand rules the game. We will refer to this situation as one where MANIFEST demand equals the EFFECTIVE demand. But if cost increases, the ED may exceed the MD. Thus, one can think of c as a quantity that regulates EFFECTIVE demand: ED=c*MD where MD stands for MANIFEST demand for children The process of childbearing may be thought of this way: =when there is no manifest demand, fertility is not within the realm of calculation of individuals and, apart from exceptions, it will be regulated almost exclusively by shifts in the supply. Societies may restrict marriage more than others, frequently to articulate allocation of property not to control childbearing. Or they may impose taboos on intercourse or they may push males to migrate etc Demand is not part of the equation at all. =when a latent demand gives way to a manifest demand the latter will be a function of a costbenefit calculation, no matter how primitive. And, in the absence of cost of regulation, the costbenefit calculation will end up yielding a quantity which will then be contrasted with the supply of children. =When there is a cost of regulation couples will translate it into units of effective demands: that is they will decide how much of the gap of worth closing given the cost of control. Suppose that the gap between supply and manifest demand is 2 children. Suppose also that contraception is subject to a huge social cost in the form of psychological costs, social sanctions, stigma, ostracism, and the material cost of contraception. The couple then translates that cost into effective demand of children and controls but only for one, say the last one (at older ages the cost of control is less and can be spread over smaller number of years of life)

8 = The first figure shows a situation where there is a gap of size A created by excess supply over manifest demand. To close this gap the couple considers contraception but with its associated cost. This makes the ED to be slightly above the manifest demand. The gap will only be partially closed. What remains is referred to as UNMET demand and is expressed in units of UNDESIRED children 5.Putting it all together We have now all the conceptual machinery to attempt to explain fertility decline in Europe and then, more recently, just about everywhere, except a few pockets. We will also need to explain the resistance to change in these pockets Some important facts about the decline of fertility i. Review of measures from the Princeton fertility study If, Ig, Im Remember meaning: If is the ratio of observed of overall fertility to what would have been observed had women been producing children as the Hutterites; Ig is the ratio of births observed to married women to the max (hutterites); Im is the ratio of observed to potential married women When there is no illegitimate fertility: If=Ig*Im Show graphs from PPP ii. Features of the decline of fertility in Europe a. With the exception of France, timing of fertility decline was compressed (see PP presentation graph); How do we determine the onset of fertility decline? With an arbitrary rule: a ten percent decline in If b. The decline was sudden and gives the impression of having engulfed many places all at once; in a matter of years it was all over. c. The decline does not follow lines associated with countries nor is it too closely related within a country with indicators of socioeconomic development, industrialization or urbanization d. Clearly, availability of knowledge about contraception might have been a bottle neck but it was not, even though the means available were not the most efficient. iii. Features of the decline of fertility elsewhere

9 In LA: onset is in some countries (except Uruguay, Argentina and Cuba); others after In Asia: precursors (Around ) are Indonesia, Thailand, Philippines, followed by China, India, Bangaldesh (After 1970) In Africa: the process is still under way (began in 1980) East African first (Kenya) and then others in West Africa (Ghana, Senegal) In all these places once it begins the decline is irreversible. It is sudden and does not always follow lines of socioeconomic development 5.2. The theories a. Theorization about low fertility decline is an old business. Even the Roman wondered why some of their citizens had a small number of children. Spencer produced a theory of pitting a tendency toward individuation versus a tendency to procreate. He suggested that urbanization enhanced the first at the expense of the second. b. Preconditions for a good theory of fertility decline: it must account for the timing and the pace. b.1. To do so (refer to supply and demand framework) it must account for three states ready: fertility decision making must be possible willing: calculations lead to advantage associated with fertility reduction able: it must be possible (not overly costly) to limit fertility b.2. No a priori dominance of economic over purely ideological factors: in fact changes of ideas may lead to changes in costs b.3. Possibility of no unifying theory c. Notestein (Thomas, Davis) and the DTT: Notestein is architect of the so-called Demographic Transition Theory (DTT); according to the propos for high fertility are eroded by three different forces: infant mortality decreases; traditional-family based economy collapses and is replaced by wage labor and a new stratification system based on achieved prestige, earnings etc benefits of children diminish and cost increase. From here, the old and well entrenched idea that development is the best contraceptive : it is through structural transformation, economic progress, advent of wage labor, increased urbanization, that fertility declines d. The contrarians: the demand for children may be low or high, what matters is to cheapen the cost of regulation. This is the position of those who created and supported the massive establishment of family planning programs in developing countries. Clearly, as such family

10 planning programs had no role to play in the European fertility decline (although public pronouncements about birth control late in the XIXth c may have had some importance) e. Caldwell wealth flow theory : based on DTT but emphasizing the idea that rationality of high and low fertility have to do with flows of wealth between generations. When the net flow is towards elderly, high fertility is rational. When the flow reverse, low fertility is rational. The problem is to identify what triggers the reversal? Here Caldwell use the idea that mass education leads to westernization : people adopt western ideas, these ideas are spread by mass education and this leads to fertility decline f. Lesthaeghe: the most important contribution is the idea that props for high fertility are entrenched in ideologies about (a) what can be decided (b) the value of individual decision making and (c) the value of individual satisfaction and pleasures vis a vis other s, including unborn generations. People become less fatalistic and believe in rationality; they detach from religion and religious institutions and emphasize material success as opposed to heavenly paradise; they establish the principle of free will. g. Diffusion (Costa Garlsson): great idea about diffusion of contraception that was misinterpreted to mean diffusion of means of contraception.when in fact ideas about control of fertility can also be diffused and become adopted. Summary: economic based theories emphasize COSTS and BENEFITS (demand side) and in doing so they focus on WILLINGNESS Family Planning type theories emphasize cost of regulation (demand side) and in doing so they focus on ABLENESS. So do most diffusion theories Caldwell and Lesthaeghe: emphasize ability to decide and costs and benefits. In so doing they privilege both READINESS and WILLINGNESS h. Reconsidering everything with Coale s RWA framework: Suppose that manifest demand were indeed relatively low but that the cost of regulation is high; the bulk of this cost is social: it is not knowledge of cc that leads to fertility control; what one needs is an ideology that supports its use. This leads to social acceptance. In addition, acceptance of the idea of LOW fertility as something useful and valuable is also possible to spread across social classes. All the more when the idea of success and wealth and status symbols are also spread. There has been diffusion of the idea of LOW TFR as acceptable as well as transformations that have facilitated the changes in costs/benefits of children and regulation. But even in the absence of these, it appears that the emergence of a very universalistic individual ideology with emphasis on material pleasures, is at root of the decline now and in the past.

11 (See article by Cleland and Wilson and Bongaarts and Watkins) This does not mean that family planning programs were not useful. They were. But as shown by Tsui this role was not decisive 6. Where are we going? Today circa 50% of the world population lives in areas with TFR<= 2 In today s world TR fluctuates quite a bit as a result of exogenous conditions that influence the timing of births and union/marriages. These fluctuations affect only low parity births since there are very few births of high parity. And childlessness is not a crucial factor since the proportion of childless women although higher today than it was yesterday has changed little. It has not driven the fertility decline Will low fertility remain? a. The story of the US around World War II: fertility was declining rapidly. It was getting close to 2.5 and then the baby boom took place. Why? See graph in PPP The essence of Easterlin s theory: TFR in a cohort is related to a comparative calculus that contrasts expectations for expenditures and life style sculpted during early socialization and the pressure of job markets during adulthood. b. The oscillations of Swedish fertility: they went from 1.5 to2.3. in a few years and then back again to 1.9. Why? Minor exogenous changes associated with public policies have some effects (housing, child care, education)