Interparental Conflict and Youth Problem Behaviors: A Meta-Analysis

Transcription

1 Journal of Child and Family Studies, Vol. 6, No. 2, 1997, pp Interparental Conflict and Youth Problem Behaviors: A Meta-Analysis Cheryl Buehler, Ph.D.,1,3 Christine Anthony, M.S.,2 Ambika Krishnakumar, M.S.,2 Gaye Stone, M.S.,2 Jean Gerard, M.S.,2 and Sharon Pemberton, M.S.2 We examined the proposition that interparental conflict is associated with internalizing and externalizing problems in youth ages 5 to 18. This examination was done by conducting a meta-anafysis of 348 statistical effects from 68 studies. The average effect size (d-value) was.32. There was considerable variability among effect sizes and this variability was associated with the average time since separation for separated/divorced parents, the socioeconomic status composition of the sample, and average parental education in the sample. The variability among effect sizes also was associated with the source of the informant used to assess interparental conflict and youth problem behaviors. Surprisingly, many of the other study characteristics we coded were not associated with variability in the effect sizes. KEY WORDS: interparental conflict; marital conflict; internalizing problems; externalizing problems; meta-analysis. Most scholars in child development and family studies have at least a tangential interest in the familial and nonfamilial factors that facilitate or inhibit child and adolescent adjustment. Deficits and inadequate models and supports in these socialization contexts place youth at risk for a whole array of adjustment problems. We conceptualize youth maladjustment as the relative inability of youth to engage successfully and appropriately in 1Professor, Child and Family Studies, University of Tennessee, Knoxville, TN. 2Doctoral Student, Child and Family Studies, University of Tennessee, Knoxville, TN. 3Correspondence should be directed to Cheryl Buehler, Child and Family Studies, JHB11S, University of Tennessee, Knoxville, TN, Electronic mail may be sent to cbuehler@utk.edu W7AJ S12.50/0 & 1997 Human Sciences Press, Inc.

2 234 Buehler et al. interpersonal relationships and in work, play, and academic activities over time with relative freedom from noxious social behaviors and burdensome emotions (Trotter, 1989). This definition focuses on the youth's inability to match emotional and behavioral responses to demands across time, people, and settings (Lorian, Cowen, & Caldwell, 1975). Internalizing and externalizing problem behaviors are important broad-band indicators of maladjustment, and as such, are salient youth mental health outcomes (Achenbach & Edelbrock, 1987). Examples of internalizing problems are depression, withdrawal, anxiety, somatic complaints, and low self-esteem. Examples of externalizing problems are aggression, delinquency, and substance abuse. We focus on one important familial correlate of youth problem behaviors the conflict between parents (married or divorced). A substantial body of literature has shown a positive association between interparental conflict (often referred to as marital conflict) and youth problem behaviors (see as examples, Cummings & Davies, 1994; Forehand, Neighbors, Devine, & Armistead, 1994; Grych, Seid, & Fincham, 1992). Of those studies which have found significant associations, the strength has ranged from about.20 to.50 (see narrative literature reviews by Buehler & Trotter, 1990; Davies & Cummings, 1994; Emery & O'Leary, 1982; Grych & Fincham, 1990). Thus, by squaring these terms, interparental conflict seems to account for somewhere between 4% and 25% of the variance in youth maladjustment. This estimation is quite broad, however, and could be better estimated by conducting a meta-analysis of the available research literature. Recognizing this important need, Reid and Crisafulli (1990) reviewed this literature using meta-analytic techniques (33 studies, 80 effect sizes). They reported an average effect size of.16 (defined as low but significant). One reason this value is lower than values suggested in recent narrative reviews may be that Reid and Crisafulli considered both measures of marital dissatisfaction and measures of interparental conflict. Many researchers have found that marital dissatisfaction is a less powerful correlate of various youth outcomes than is interparental conflict (Cummings, Davies, & Simpson, 1994; Jouriles, Farris, & McDonald, 1991; Katz & Gottman, 1993). As such, it may be that by considering both marital dissatisfaction and interparental conflict in their analysis their results have underestimated the real magnitude of the association between interparental conflict and youth problem behaviors. On the contrary, their findings might not be underestimated given that most narrative literature reviews overestimate the magnitude of effects by not adequately considering nonsignificant findings. Thus, the purpose of our study was to build on Reid and Crisafulli's (1990) work by examining the proposition that interparental conflict (IPC) is associated positively with youth problem behaviors (YPB), paying specific

3 Interparental Conflict 235 attention to conceptualizing clearly the construct of IPC and by including assessments of youth internalizing problems. With marital dissatisfaction disentangled from IPC, researchers have become even more focused recently by suggesting that IPC is multidimensional, including at least six subdimensions: frequency, intensity, mode or form of expression, chronicity, content, and degree of resolution (Cummings & Davies, 1994; Davies & Cummings, 1994; Grych & Fincham, 1990). However, because this conceptual specification is a recent development, very little research exists on some of the subdimensions, such as intensity and chronicity. Most of the existing literature focuses on frequency of conflict/disagreements or mode of expression. Accordingly, our meta-anaiysis summarized the research findings from these more frequently studied subdimensions of IPC. The few studies with a sole focus on intensity, chronicity, content, or degree of resolution were not included in our review because of an inadequate data base. Frequency of IPC is defined conceptually as the frequency of disagreements between parents about various issues in family life (Buehler, Krishnakumar, Anthony, Tittsworth, & Stone, 1994). Mode of expression (labeled "method of handling" by Kempton, Thomas, & Forehand, 1989) typically has been conceptualized as either hostile verbal or physical ways of addressing or showing the conflict (for a review, see Davies & Cummings, 1994). We believe this conceptualization is too limited and suggest that the idea of conflict styles be used to conceptualize mode of expression. As such, conflict styles refer to the behaviors, affect, and/or strategies used to manage disagreements or oppositional interests between parents. The literature points to five possible IPC management styles: overt (physical and/or verbal), covert, cooperative, avoidant, and withdrawn (Buehler et al., 1994; Camara & Resnick, 1988; Katz & Gottman, 1993). An overt conflict style is defined as hostile behaviors and affect which indicate direct manifestations of negative connections between parents. Identifying characteristics include: belligerence, contempt, derision, screaming, insulting, slapping, threatening, and hitting (Buehler et al., 1994). A covert conflict style is defined as hostile behaviors and affect that reflect passive-aggressive ways of managing conflict between parents (Buehler & Trotter, 1990). Conceptually, we suggest two components: triangling children and global covert behaviors. Identifying characteristics of the triangling component include: trying to get the child to side with one parent; scapegoating the child; using the child to get information about the other parent when self does not want to ask the other parent directly; having the child carry messages to the other parent because self does not want to relay the information; denigrating the other parent in the presence of the child when the other parent is not present; and denigrating the other parent

4 236 Buehler et al. to the child in the presence of the other parent, but acting as though the other parent is not present. Identifying characteristics of the global covert component include resentment, upsettedness, or unspoken tensions manifested between parents in subtle, indirect behaviors and affect which do not involve the children. A cooperative conflict style is defined as behaviors and affect which allow for continued interaction and mutual effort in spite of differences and even fundamental disagreements (Horowitz, 1967). Identifying characteristics include: negotiation, reasoning, active listening, affirming the other's parenting abilities and endeavors, and a willingness to place children's needs above individual interests and emotions. An avoidant conflict style is defined as behaviors and affect that indicate an unwillingness to address issues of difference or disagreement. Identifying characteristics include: denying that a difference or disagreement exists, speaking abstractly about issues, using humor to sidetrack discussions of disagreements, and keeping so busy with other aspects of life that issues are not addressed (Fitzpatrick, 1988). A withdrawn conflict style is defined as behaviors and affect that remove a person from existing, active conflict interactions. Identifying characteristics include: speaker withdrawal such as clamming up, walking out when things get tense, and listener withdrawal such as stonewalling (Gottman, 1994). Withdrawal differs conceptually from avoidance in that an asymmetry exists for withdrawal with one partner, rather than both, distancing him or herself from the conflictual interaction (Gottman, 1994). PROCEDURE Research reports reviewed in this study were located using several techniques (as suggested by Hedges & Olkin, 1985; Hunter & Schmidt, 1990). We first went through our extensive project files of published and nonpublished articles and book chapters. Next, a computer search was conducted to identify articles that were not included in our project files. Several computerized data bases were searched (e.g., Psychological Literature, Social Science Index, and Dissertation Abstracts). Third, the reference lists of recent narrative literature reviews were scanned to identify new articles. Finally, a manual search was done on the most recent 15 years of about 10 relevant journals. Although this was a comprehensive search, it is likely that we have missed a few relevant reports. To address this limitation we have calculated the Fail-safe N associated with our findings. This statistic estimates the number of nonsignificant, unretrieved effect sizes that would need to exist to invalidate our findings.

5 Interparental Conflict 237 Reports needed to meet the following criteria to be included in this meta-analysis: 1. The assessments of IPC and YPB needed to fit with the conceptual definitions detailed above. 2. The sample needed to include married or divorced families who had children somewhere between the ages 5 to 18. Data on stepfamilies were not included in this review because the focus of assessment of IPC often was not clear. As such, a central criteria for inclusion was that the target child be a product of the marriage of focus. 3. The report needed to be published in English. 4. The report needed to have statistical data available to calculate an effect size. Text reports of nonsignificant findings were included because the effect size can be adequately (but not exactly) estimated by assuming a probability level of.50 (Z score of 0; Rosenthal, 1991). Using these techniques and criteria, we located 68 useable studies. Thus, this meta-analysis was based on twice as many studies as that conducted by Reid and Crisafulli (1990), indicating a substantial increase in research on IPC and youth adjustment during a 6-year time span. These 68 studies yielded 343 effects. There were many more effect sizes than studies because many researchers distinguished between internalizing and externalizing youth problems, and reported separate results for male and female youth. In cases where the author reported a coefficient based on a total youth problem score, as well as results based on separate internalizing and externalizing scores, we coded only the latter to avoid redundancy and to capture an adequate level of specificity. Using the same logic, in cases where the author reported associations calculated using the entire sample as well as those separated by sex of youth, we coded the latter data. Ten percent of the studies were coded by a second coder and there was 86% agreement between the two coders, averaging across all coded variables. This was too low and resulted in a reexamination of all coded data by the first author. This reexamination and revision resulted in a 99% accuracy rate for all coded data. RESULTS The first step in our analysis was to examine the distribution of effect sizes by dimension of IPC (see Table 1). Three observations were important to us. First, most researchers have focused their inquiries on parents' use

6 238 Buehler et al. Table 1. Frequencies and Means of Effect Sizes within Different Categories of Interparental Conflict Conflict Variable Conflict/disagreement Overt conflict style Covert conflict style Withdrawn conflict style Avoidant conflict style Cooperative conflict style Composite assessment Frequency Percent Mean (SD) (.32) (.36) (.38) (.42) (.45) (.85) (.45) athe composite assessment included measures of two or more subdimensions, e.g., frequency of disagreements; and the use of an overt conflict style. The most common measure in this group was the O'Leary Porter Scale. of an overt conflict style or on a global/composited assessment of IPC (total of 75% of effects). Second, we found very little research that focused on parents' use of avoidant or cooperative conflict styles. To facilitate a clear interpretation of the results, these effects were dropped from subsequent analyses. Third, the average association between parents' use of an overt, hostile conflict style and YPB looked stronger than the association between the mere frequency of interparental disagreement and YPB. This observation was examined statistically using a one-way analysis-of-variance, and we found no overall differences between the categories of interparental conflict, F(4,343) = 1.30, p =.27. Accordingly, subsequent analyses were conducted on the total sample of effect sizes (excluding the effects on avoidance or cooperation). However, it is interesting to note that t-tests indicated that the average effect sizes for parents' use of an overt conflict style (.35) and for the composite assessment of IPC (.34) were greater than the average effect sizes using covert conflict style (.28), withdrawn conflict style (.27), and the frequency of disagreements (.19). The average effect size was.32 (SD =.41). The 95% confidence interval for this value was.30 to.34. This effect size was twice as large as that reported by Reid and Crisafulli (1990), and also was about twice as large as the average effect reported by Amato and Keith (1991) that reflected the possible effects of divorce on child adjustment. An effect size of.32 falls between Cohen's (1977) description of a small (.20) and medium (.50) effect. This calculation is robust to discrepant, unretrieved reports, given that 1,467 null effects would be needed to refute this finding (the Fail-safe N). Thus, there is increasing evidence that conflict between parents is one of the several important familial correlates of internalizing and

7 Interparental Conflict 239 externalizing YPB. However, this conclusion must be tempered given that 66% of the effects in this meta-analysis were nonsignificant. The next step in the analysis was to examine the 343 effects for homogeneity. We were not surprised to find considerable variability, 2B(362) = , p <.001. Consequently, this variability was examined to see if it could be explained by various study characteristics. We divided study characteristics into three sets of variables: conceptual variables, subject characteristics, and methodological variables. Conceptual Variables We already presented the results of the effects of conceptual distinctions in the assessment of IPC. There were no overall differences in the effect sizes across several subdimensions of IPC (although the average effect sizes associated with an overt conflict style and the composite measure of IPC and YPB were greater than the effects associated with a covert conflict style, a withdrawn conflict style, and the frequency of interparental disagreement). The second conceptual distinction examined was in the assessment of YPB. Three categories of effects were compared: (a) those that used externalizing problems as the dependent variables; (b) those that used internalizing problems; and (c) those that used a combination of internalizing and externalizing scores to derive a total problem behavior score. The average effect sizes for these three YPB categories were.39,.31, and.21, respectively. Using a one-way ANOVA, these effects differed from one another F(2,345) = 4.06; p =.02, with the effect size for IPC and externalizing YPB being significantly greater than that for IPC and the combined measure Of internalizing and externalizing assessment of YPB. Subject Characteristics Ten subject characteristics were coded for each effect, when adequate data were provided in the reports. These were: parents' marital status (married, separated/divorced, mix); and if separated or divorced, the number of months separated; gender of child (all male, all female, mix), percent of boys in the sample; child age range in sample; average age of children/youth in the sample; race composition in sample (mostly white, mostly black, mix); SES composition in the sample (middle, lower-middle, lower, and combination of these); average income level of sample; and average educational attainment of sample (less than high school, completed high school, some college).

8 240 Buehler et al. Variability in effect size was not related to the following subject characteristics: parent's marital status, F(2,342) =.22; p =.81; sex of child sample composition, F(2, 345) = 2.39, p =.09; percent of boys in the sample, r =.08, n = 321, p >.05; child age range in sample, F(10,305) =.72, p ~.71; the average age of the child in the sample, r = -.11, n 234, p >.05; the racial composition of the sample, F(2,237) =.10; p =.90; and the average income level of the sample, r = -.07, n = 125, p >.05. There were three significant explanatory variables: time since separation/divorce (when relevant), SES, and educational attainment. Time since separation/divorce was inversely related to the effect size between IPC and YPB, r = -.21, K = 104, p <.05. This means that the association between IPC and YPB was stronger for recently separated families than families in which the separation or divorce was more distant. The average affect size also was related to the SES composition of the sample, F(7,168) = 2.11, p The effect size was greater in samples that were predominately middle class than in samples that included lower, middle, and upper-middle class respondents, t(93) = 2.60, p <.01. Also, the effect size was greater in samples that were predominately lower class than in samples that included lower, middle, and upper-middle class respondents, t(68) = 2.66, p <.01. Finally, the average effect size varied by the average educational attainment of the sample, F(2,155) = 8.41, p <.001. The average affect size in samples (a) in which most subjects had not completed high school was.60 (SD =.42); (b) in which most subjects had completed high school was.03 (SD =.40); and (c) in which most subjects had completed some college was.30 (SD =.35). Thus, the association between IPC and YPB seems to be strongest in samples with low educational attainment, and moderate in samples with higher educational attainment. There seems to be little association between IPC and YPB in samples where most subjects had completed high school, but had gone no further. Methodological Variables Fifteen methodological variables were coded for each effect size, when data were available. Publication year was unrelated to effect size, r =.09, n = 348, p >.05. Two methodological variables focused on sampling: sample sizes and sampling selection techniques. The average sample size was 89 subjects (SD = 147). The range was 8 to Sample size was not related to effect size, r =.01, n = 336, p >.05. Most of the studies used convenience sample (74%), and the sampling procedure was not related to effect size, F(3,328) =.75;? =.52.

9 Intel-parental Conflict 241 Several of the methodological variables focused on measurement. Most of the studies assessed subjects at only one point in time (89%). Although the mean effect size for cross-sectional data (.32) was slightly greater than that for longitudinal data (.28), this difference was not significant, F(2,345) =.59, p =.55. Effect size was related to the identity/role of the informant of IPC, F(6,341) = 2.16, p =.05. Follow-up t-tests indicated that the effect size was greater when mothers (or primary parents) were the reporters (.39) than when fathers were the reporters (.20). We were surprised that the effect size calculated using youth reports of IPC was not higher than other effect sizes. Emery (1982) suggested that IPC is salient primarily when the child is exposed to the conflict. If this were the case, then youth reports of IPC likely would be more highly correlated with their problem behaviors than other informants' reports of IPC (because of increased saliency and variability). However, this was not the case in this set of reviewed studies. Almost all of the effects were based on multiple-item measures of IPC (97%). Multiple-item measures had a slightly higher mean effect size (.32) than did single-item measures (.29), but this difference was not significant, F(l,346) =.07, p =.79. The method of assessment of IPC was primarily through questionnaires (78%). Based on 11 effect sizes, observational assessment of IPC yielded a higher mean effect size (.48) than that yielded by questionnaires (.32); however, method of assessment was unrelated to effect size, F(6,341) =.69, p =.66, probably because of the great disparities in frequencies. The last variable coded for IPC was the actual measure used to assess IPC. We had expected that effect sizes based on the Conflict Tactics Scale would be greater than those based on the O'Leary-Porter Scale because the CTS focuses specifically on verbal and physical overt conflict behavior. However, this was not the case, F(4,343) =.58, p =.67. Shifting to the assessment of YPB, the identity/role of the informant of problem behaviors was related to effect size, F(6,341) = 4.69, p < Father's reports of YPB produced much smaller effects (.10) than the reports made by mothers/primary parent (.40), and by teachers (.39). Again, most of the measures of YPB consisted of multiple questions/scales (99%), and the effect sizes based on single vs. multiple items were not different, F(l,346) =.0023, p =.96. To the contrary, the method of collecting data on YPB was related to effect sizes, F(4,343) = 2.42, p =.05. Effect sizes based on questionnaires (.34) were greater than those based on observational data (-.07). About 39% of all effect sizes were based on one of the Achenbach scales (i.e., CBCL, YSR, TRF). However, effect size was unrelated to the specific assessment device used, F(6,341) = 1.64, p =.14.

10 242 Buehler et al. In terms of data analysis, we recorded whether or not statistical controls were used and found no difference between the two mean effects, F(l,346) = 2.62, p =.11. Most of the controls were background variables, such as income, but a few analyses controlled for other familial variables, such as parenting behaviors. The last methodological variable examined was a general assessment of methodological quality undergirding the effect. The code for the assessment of quality was developed for this study, building on the work by Amato and Keith (1991). The scale ranges from 0 to 4, with 1 point being assigned for each of the following aspects: sample quality, research design, measurement, and analytic design. For sampling,.5 point was assigned if the effect was based on 100 or more subjects, and.5 point if the sample was selected using random or stratified random procedures. For research design, 1 point was assigned if an experimental or longitudinal design was used. In terms of measurement,.5 point was assigned if IPC was assessed using multiple methods or.25 if multiple informants were used. Multiple methods or informants in assessing YPB were accounted for similarly. Although each effect could receive a maximum of 1 point for measurement, we also assigned.5 if IPC and YPB were assessed by different methods or by different informants, to recognize the improvement in measurement when bias due to shared method variance is reduced. Finally, 1 point was assigned if the effect was based on multivariate statistical techniques that help purify the association estimate by removing shared association with third variables (e.g., structural equation modeling, multiple regression, partial correlation). The average quality score was.41 (SD =.77), ranging from 0 to Quality was not related to effect size, r , n = 348, p >.05. In summary, the average effect size of the association between IPC and YPB was.32 (SD =.41), ranging from to The average was calculated from 348 effects from 68 studies. Variability in these effects was explained by specific subject characteristics and methodological variables. DISCUSSION We organize our discussion of these findings around five main ideas: (a) the consistent existence of an association between IPC and YPB; (b) the conceptualization and assessment of IPC and YPB; (c) the effects of sex and age of child; (d) sampling effects; and (e) the future exploration of explanatory mechanisms. In their narrative literature reviews, Emery (1982) and Davies and Cummings (1994) have contended that there is a consistent and important

11 Interparental Conflict 243 association between interparental conflict and youth problem behaviors. We agree with their assertions and have provided data from 68 studies to support their conclusions about consistency. The findings from our study suggest a stronger association than those reported by Reid and Crisafulli (1990), and provide evidence that the effect describes the association between IPC and internalizing problems in addition to externalizing problems. One of the strengths of a meta-analysis is that it adequately takes into consideration nonsignificant findings, whereas most narrative literature reviews typically underestimate the number and effect of nonsignificant findings. Accordingly, the average effect size reported in a meta-analysis usually is smaller than that reported or implied in narrative reviews. That was the case in this literature. Grych and Fincham (1990) reported that 15 of 19 (79%) reported a significant association between IPC and YPB. Buehler, Anthony, Stone, Krishnakumar, and Tittsworth (1995) reported that 52% of the associations between use of an overt conflict style and youth problem behaviors were significant, and that the magnitude of the association ranged from.20 to.49. The number of significant findings (34%) and the average effect size (.32) found in this meta-analysis were substantially lower than reported in these narrative reviews. To place our findings in context, we conducted a follow-up analysis in which we calculated the average effect size using only significant effects. The average effect size for these 119 effects was.67 (SD =.37, Range = -.58 to 2.85). By comparing the.67 (a strong effect) with the.32 (weak to moderate), one can see the consequences of not adequately considering nonsignificant findings in a review of literature. Although the magnitude of the association is best described as somewhere between weak and moderate in strength, it is important to highlight that almost half of the effects in this study were partialized. This means that the association has been purified by controlling for influences from other variables such as background factors and quality of parenting, Partialized effects usually are smaller than zero-order effects and represent a purer and more robust estimation. In addition, it is important to recognize that many familial and nonfamilial factors influence youth maladjustment, and we would not expect strong effects (i.e.,.60 and above) from any one factor. Rather, we expect that each factor has a small influence, and that one of the tasks for researchers is to estimate the consistency and magnitude of each effect and then to study the effects in conjunction with one another to determine the independent, joint, and interactive effects of multiple socialization influences. In terms of conceptualization, Grych and Fincham (1990) have made a very strong argument that IPC is a multidimensional construct. We agree

12 244 Bnehler et al. and believe the next generation of research needs to distinctly measure different dimensions. We were able to distinguish between frequency of disagreement and the use of three different conflict styles (overt, covert, and withdrawn) in this meta-analysis. However, the data on conflict styles other than overt was very limited. Future research needs to remedy this important omission. The findings from this study suggested that parents' use of an overt conflict style is more strongly related to YPB than is the mere frequency of disagreement. Accordingly, future research should assess each construct independently. We found that mothers' reports of IPC and YPB produced stronger effects than fathers' reports, even when sieparate informants were used to report on YPB (e.g., teachers). It may be that fathers' reports have less variance, attenuating the correlation between IPC and YPB. Or, it may be that fathers are not the best reporter of what is going on in the marriage. We also found that the observer reports of IPC produced stronger effect sizes between IPC and YPB, although the number of effects was low. Future research needs to include more observational assessments of IPC so that this finding can be replicated. If the effect size remains high, this will indicate we need to learn about marital conflic processes from observers' coding of marital interaction, as well as from mothers and children. Grych and Fincham (1990) concluded that the extant literature indicates a relationship between IPC and both internalizing and externalizing youth problems. Reid and Crisafulli (1990) conducted their meta-analysis only on externalizing problems. The findings from our meta-analysis extend their work by indicating that the association also is present for youth internalizing problems. Our findings suggest that we will learn more about youth problem behavior if researchers separately assess externalizing and internalizing problems, rather than compositing the two into a total problem behavior score. It also would help if we begin to examine which aspects of these broad-band assessments are influenced by IPC. For example, within the spectrum of internalizing problems, is depression more strongly associated with IPC than somatic complaints? A final point about the assessment of YPB addresses the issue of relatively high correlations between measures of internalizing and externalizing youth problems, and the effect this high degree of association has on the interpretation of predictors of YPB. Although some researchers fail to report the correlation between internalizing and externalizing problems in their samples, it seems that the association ranges from about.30 to.70 (9% to 50% shared variance). In samples with substantial shared variance, it is not possible to identify unique predictors of externalizing and internalizing problems without controlling for this shared variance. For example, it is not possible to interpret accurately a

13 Interparental Conflict 245 significant correlation between an overt conflict style and youth externalizing without simultaneously controlling for youth internalizing problems. Very few researchers have adequately controlled for alternate problem behaviors, and as such, we know very little about the unique predictors for youth internalizing and externalizing problem behaviors. Future research should address this limitation. Several past reviewers have concluded that the association between IPC and YPB is stronger for boys than girls (Grych & Fincham, 1990; Reid & Crisafulli, 1990). Our analysis did not support this conclusion. Although the effect size was higher for boys (.32) than girls (.23), this difference was not significant, t(136.84) = 1.16, p =.25. As a specification to the idea of sex of child differences, Emery (1982) hypothesized that boys may have higher externalizing problems in the face of IPC, whereas girls may have higher internalizing problems. We found no support for this hypothesis. As a last check, we examined data testing the idea that boys and girls might differ only in clinical samples. This sex difference did not emerge, t(36) = 1.04, p =.31. At this point in time, we conclude from the analysis of data from these 68 studies that the association between IPC and YPB is similar for sons and daughters. Most past reviewers have concluded that no one age group of children appears to be particularly vulnerable to the effects of IPC (Emery, 1982; Grych & Fincham, 1990). Our findings supported this conclusion, although there was enough variability in effect sizes across age groups that it seems the factor of age needs additional research. The findings from our study indicate two important points about sampling. Past narrative reviewers have concluded that the association between IPC and YPB is stronger in clinical samples than nonclinical (Davies & Cummings, 1994; Emery, 1982; Grych & Fincham, 1990). Reid and Crisafulli (1990) did not find this difference in their meta-analysis and neither did we. We additionally probed this issue by conducting a two-way analysis-of-variance, with both clinical status and sex of child as factors, to see if there was an interaction between sex of child and clinical status. We did not find one. Our second point about sampling is that we did not find a significant difference between samples of married and divorced parents. Reid and Crisafulli (199) did not include effects from divorced parents because they believed the association to be different for divorced families. We did not find a difference in the association between IPC and YPB for these two family configurations, and conclude from this that IPC is an important correlate of YPB in both kinds of families. Given the findings from the this study, it seems to us that an important next step is to carefully begin examining the mediating mechanisms be-

14 246 Buehler et al. tween IPC and YPB so that we can better understand how to shape interventions. Several researchers have begun this important process and have been focusing on parenting behaviors (e.g., Fauber, Forehand, Thomas, & Wierson, 1990), youth attributional processes (e.g., Grych, Seid, & Fincham, 1992), youth emotional insecurity (Davies & Cummings, 1994), and characteristics of the conflict interactions such as degree of resolution (Cummings & Davies, 1994). We believe that the future knowledge base on the effects of interparental conflict on youth adjustment will be strengthened by careful attention paid to the clear conceptualization of IPC and YPB, along with the extensive testing of analytic models for differences across potential moderating variables such as SES and marital status. This effort will result in a body of research that can be responsibly used to plan intervention programs for youth and their families. ACKNOWLEDGMENTS We would like to thank Kristie Pankratz for her help with data entry. The reference list for the studies in the meta-analysis are available from the senior author. REFERENCES Achenbach, T. M., & Edelbrock, C. (1987). Manual for the youth self-report and profile. Burlington: University of Vermont, Department of Psychiatry. Amato, P. R., & Keith, B. (1991). Parental divorce and adult wellbeing: A meta-analysis. Journal of Marriage and the Family, 53, Buehler, C, Krishnakumar, A., Anthony, C., Tittsworth, S., & Stone, G. (1994). Hostile interparental conflict and youth maladjustment. Family Relations, 43, Buehler, C, & Trotter, B. B. (1990). Nonresidential and residential parent's perceptions of the former spouse relationship and children's social competence following marital separation: Theory and programmed intervention. Family-Relations, 39, Camara, K. A., & Resnick, G. (1988). Interparental conflict and cooperation: Factors moderating children's post-divorce adjustment. In E. M. Hetherington & J. D. Aratesh (Eds.), Impact of divorce single parenting and stepparenting on children (pp ). Hillsdale, NJ: Erlbaum. Cohen, J. (1977). Statistical power analysis for the behavioral sciences. New York: Academic Press. Cummings, E. M., Davies, P. T. & Simpson, K. S. (1994). Marital conflict, gender, and children's appraisals and coping efficacy as mediators of child adjustment. Journal of Famify Psychology, 8, Cummings, E. M., & Davies, P. (1994). Children and marital conflict: The impact of family dispute and resolution. New York: The Guilfoid Press. Davies, P. T., & Cummings, E. M. (1994). Marital conflict and child adjustment: An emotional security hypothesis. Psychological Bulletin, 116, Emery, R. E., & O'Leary, K. D. (1982). Children's perceptions of marital discord and behavior problems of boys and girls. Journal of Abnormal Child Psychology, 10,

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