Journal of Youth and Adolescence, Vol. 19, No. 6, 1990
Parent-Adolescent Congruence for Adolescent Substance Use Jennifer Langhinrichsen, 1,3 Edward Lichtenstein, 1,2,4 John R. Seeley, 2 H y m a n Hops, 2 Dennis V. Ary, 2 Elizabeth Tildesley, 2 and Judy Andrews 2 Received March 28, 1989; accepted July 25, 1990
Parental reports of adolescent substance use were compared to the adolescents' self-reports using identical scales. Congruence was defined as exact agreement on whether adolescents were current users, ex-users, or never-users. Both parents were found to be less accurate in predicting their adolescents' alcohol use compared to cigarette or marijuana use. Single mothers were significantly less likely to be congruent than were mothers from two-parent households. Mother and father congruence on all substances was unrelated to the adolescent's sex, race, or after school employment. For both parents, congruence for adolescent marijuana use was significantly related to the age and GPA of the adolescent. Congruence may also reflect important properties of family functioning, as significant relations were found between both adolescent and parent ratings of family cohesion and parent-adolescent congruence on perceptions of marijuana use.
INTRODUCTION Substance use and abuse among youth are ongoing areas of concern for researchers, policy makers, school officials, and parents. The data disThis research was supported by Grant DA03706 from the National Institute of Drug Abuse (Hyman Hops, Principal Investigator). 1University of Oregon. 2Oregon Research Institute. 3jennifer Langhinrichsen is a doctoral candidate in psychology interested in adolescent and family interactions. The other authors are psychologists or data analysts working on family influences on substance use and mental health. aRequests for reprints should be sent to Edward Lichtenstein, Oregon Research Institute, 1899 Willamette, Eugene, Oregon 97401. 623 004%2891/90/1200-0623506.009 1990PlenumPublishingCorporation
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cussed here are part of a larger study that addresses how parental influences affect or interact with adolescents' use of alcohol, tobacco, and marijuana (e.g., Hops et aL, 1990; Andrews et al., 1990). A practical goal of the project is to learn what parents might do or not do to discourage their adolescents from substance use. It is believed that parenting practices are related to adolescent's decisions regarding substance use (Glynn, 1984; Patterson and Dishion, 1985; Dishion and Loeber, 1985). We assume that parental practices with regard to their adolescent's substance use are determined at least partly by their knowledge of the adolescent's user status. Parents who believe their adolescent is smoking or drinking alcohol are likely to behave differently than parents who are unaware of their adolescent's substance use. Parental monitoring, knowing where the adolescent is and what he/she is doing, has been found to be inversely related to antisocial behavior (e.g., Dishion and Loeber, 1985; Steinberg, 1986). Patterson and Bank (1989) have shown that parental monitoring sets the stage for the adolescent's involvement (or acceptance) in the peer group and leads to antisocial behavior. Low levels of monitoring may provide adolescents with greater opportunity to experiment with substances, especially within the peer group setting. It is of interest, therefore, to determine if parents' perceptions of their adolescent's use are accurate. Since accuracy rests on direct knowledge of the adolescents' beh a v i o r - w h i c h is often very difficult to o b t a i n - w e derived a parent-adolescent congruence measure by comparing both parties' reports. Congruence was defined as a match between m o t h e r ' s or father's reports of the adolescent's use of alcohol, cigarettes, and marijuana and the adolescent's self-reported substance use. Both adolescents and parents reported substance use on the same scales. This paper provides descriptive data while examining the impact of a number of theoretically and practically relevant variables on p a r e n t adolescent congruence. First, congruence was examined descriptively by considering frequency, stability across substances, and consistency between parents in the same family. It was hypothesized that there would be greater congruence for licit substances such as cigarettes than for illicit substances such as marijuana because adolescents will tend to be more open with their parents about their use of licit drugs. Alcohol congruence was predicted to be higher than marijuana congruence and lower than cigarette congruence. In terms of consistency between parents in the same family it was hypothesized that mothers would tend to be more congruent with their adolescent than would fathers. This hypothesis was based on the evidence that the mother is the primary parent in terms of adolescent management and monitoring and has better knowledge of her adolescent's behavior
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(Dishion and Loeber, 1985). It was further hypothesized that single mothers would show lower congruence due to their diminished ability to monitor their adolescent's behavior. Second, age, gender, and school achievement were examined in relation to the congruence variable. It was hypothesized that there would be greater congruence for younger adolescents than for older adolescents. Developmentally, it was expected that older adolescents are tending to individuate and separate from their parents (Hartup, 1983) and become more influenced by peers (Krosnick and Judd, 1982). Part of the differentiation process may involve the adolescent's engaging in more covert behaviors and it was expected that these unshared behaviors would reduce congruence. It was also hypothesized that congruence would tend to be higher for boys than for girls on the basis of cultural stereotypes that tend to a t t r i b u t e less use to girls, causing parents to underestimate their daughters' use, which would reduce congruence. Due to the cultural expectation that adolescents who do well in school tend to avoid substance use, it was hypothesized that there would be more incongruence for adolescents with higher GPAs, in keeping with the tendency of these parents to report that their adolescents are nonusers. Third, congruence was examined in relation to parents' and adolescents' self-reported perceptions of family cohesion and conflict. While family conflict is found to be associated with the level of adolescent substance use (e.g., Baer et al., 1985; Hops et aL, 1990), the relationship between conflict and congruence remains unexplored. It was hypothesized that mothers and fathers who rated their home as high in conflict or low in cohesion would be less likely to be congruent with regard to their adolescent's substance use. Likewise, adolescents who rated the home as high in conflict and low in cohesion were expected to be less able to confide in their parents, resulting in decreased congruence.
METHOD
Subjects Adolescents and their families were recruited to participate in a longitudinal study focused on the family's influence on adolescent substance used. Participating families were required to have at least one adolescent between 11 and 15 years of age. The families were recruited from newspaper, television, and radio advertisements in a moderate-sized northwest urban area. There were 763 target adolescents, 390 females and 373 males. The mean age of the target adolescents was 13.2 years, with a range from
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10 to 16.6 years. Seven hundred fifty-eight mothers participated and data were collected from 420 fathers. The N for specific analyses is usually lower because of missing data for one or another variable.
Procedure
All of the adolescents completed a self-report questionnaire assessing the extent of their substance use. Parents accompanied the adolescents to the assessment and simultaneously, but in a separate location, filled out a questionnaire that was parallel in nature. There was concern that adolescents might underreport their substance use in a setting where their parents were also being assessed. Two safeguards were employed to increase the validity of the adolescents' responses. First, all subjects were assured of the confidentiality of their responses. Second, with regard to cigarette smoking, each adolescent provided an expired air sample, which he or she was told would provide objective information about his or her smoking status. This bogus pipeline procedure has been found to increase the accuracy of adolescent reports of their tobacco use (Murray et al., 1987). It was hoped that this increased accuracy would generalize to the adolescents' reports of other substance use. Each family was paid $35 for the completion of the assessment.
Measures
Substance Use. Adolescents indicated their lifetime use of cigarettes, alcohol, and marijuana by checking the most applicable category on a 7point (cigarettes, marijuana) or 8-point (alcohol) rating scale. Potential responses ranged from "I have never smoked cigarettes, not even once" to "I smoke cigarettes at least once per day." The additional alcohol item was "drink only on special occasions with my family." For the purposes of this study, adolescents' responses were collapsed into three categories: (a) those who had never used the substance, (b) those who had used the substance in the past but were not current users, and (c) those who were currently using the substance (which included "special-occasion" users of alcohol). Each parent completed a parallel scale with which to describe his or her teen's substance use. Parental responses were collapsed into the same three categories. Congruence. Congruence was defined as exact agreement between parent and adolescent using the collapsed three categories. Degree of congruence was assessed via weighted kappa (Cohen, 1968). The kappa weights
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were determined a priori; weights of 1 and 2 were assigned to pairs off by one and two categories, respectively. Demographic Factors. D e m o g r a p h i c data collected i n c l u d e d the adolescents' age, sex, race, grade, grade point average, and after-school work history and the parents' marital status, education, and gender. Family Relations. Perceptions of cohesion and conflict were assessed for both parents and adolescent via the cohesion and conflict subscales of the Family Environment Scale (FES; Moos, 1981). Each FES subscale consisted of nine items which were presented in a true/false format. The conflict subscale was designed to measure family members' perceptions of the degree to which open expressions of anger and aggression are characteristic of the family. The cohesion subscale was designed to measure the extent to which family members are thought to be involved with, supportive of, and helpful to one another.
RESULTS
Degree of Congruence The perceptions of 70% of the sampled mothers were congruent (exact agreement) with their adolescent's reported cigarette use and 78% were congruent with marijuana use. Only 54% of the mothers correctly identified their adolescent's alcohol-use status. The corresponding values for father-adolescent agreement were 70, 80, and 55%, respectively. While the values for mothers and fathers are similar, a test of the hypothesis that mothers would be more congruent than fathers requires a comparison of parents from the same household. Therefore, the congruence of mothers and fathers from the same households was compared for each substance using the McNemar test for related samples (Siegel, 1956). No differences between mothers and fathers were found for smoking (~2 = .57, n.s.) and alcohol (2z = .9, n.s.) but significant differences were found for marijuana (2a = 6.6, p < .05). More fathers (20.6%) than mothers (16.5%) were incongruent for marijuana. Table I presents parent-adolescent agreement by the level of the adolescent's reported use. It can be seen that, for cigarettes and marijuana, congruence is highest for nonusing adolescents, but for alcohol, congruence is lowest for nonusers. Weighted kappa was used as chance-corrected measure of agreement to quantify parent-adolescent congruence. For mothers and adolescents, weighted kappas were .36 for alcohol, .59 for cigarettes, and .61 for marijuana. For fathers, the corresponding values were .41, .54, and .56. All
Alcohol Cigarettes Marijuana
(n = 726) (n = 734) (n = 727)
.39 .85 .92
Never-users .66 .61 .59
Ex-users .52 .54 .41
Current users
Mother-adolescent congruence
(n = 418) (n = 420) (n = 417)
.51 .89 .94
Never-users
.60 .47 .43
Ex-users
Father-adolescent congruence
.54 .52 .42
Current users
Table I. Percentage of Congruent (Exact-Agreement) Parent-Adolescent Pairs by Level of Adolescent's Use
t~
~r
0~
t,O O0
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629
values are highly significant (p < .001). Consistent with the percentage agreement data, for both parents, the highest weighted kappas were obtained for the adolescent's marijuana use and the lowest amount of agreement was obtained for alcohol use. This did not support the prediction that congruence would be greater for licit drugs than for illicit drugs such as marijuana. As shown in Table II, the majority of incongruent mothers and fathers significantly underestimated, rather than overestimated, their adolescent's reported use of marijuana and cigarettes. However, incongruent parents were about equally likely to over- or underestimate the drinking behavior of their adolescent. The consistency of parent-adolescent congruence across substances was assessed by examining the number of mother-adolescent and father-adolescent pairs congruent for all three substances, any two, any one, or none. Mothers and fathers were equally consistent across substances. Approximately 35% of parents were congruent for all three substances, 39% were congruent for any two, and only 7% were not congruent for any substance.
Congruence, Age, Sex, and School Achievement Single mothers were significantly more likely to be incongruent with their adolescent's reports of substance use for any one, two, or all three substances than were mothers from two-parent households (Z2 = 7.8, p < .05). Adolescents' grade level was split to compare those in the ninth grade and above (high school) with those in the eighth grade and below (middle school), although about three-fourths of the adolescents were in middle schools. As shown in Table III, grade level was significantly related to
Table II. Percentage of Parents who Over- and Underestimate Their Adolescent's Self-Reported Substance Use ~ overestimating %underestimating Alcohol Mothers (n = 726) 24.2 21.6 Fathers (n = 418) 22.7 22.0 Marijuana Mothers (n = 727) 6.6 15.8" Fathers (n = 417 5.3 14.9" Cigarettes Mothers (n = 734) 8.4 20.1" Fathers (n = 420) 6.7 23.1" ap < .001, difference in proportion between overestimaters and underestimaters.
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Langhinrichsen et al. Table I!1. Percentage of Parent-Adolescent Noncongruence by Substance and Adolescent's Grade Level Cigarettes Mother Father Alcohol Mother Father Marijuana Mother Father
~ 8 t h grade
~ 9 t h grade
29070 (n = 148) 25070 (n = 78)
31% (n = 69) 4207o** (n = 47)
48% (n = 243) 48% (n = 146)
41% (n = 90) 37%* (n = 41)
19070 (n = 94) 17070 (n = 51)
33%** 69) 30%** (n = 33)
*p < .05. **p < .001.
marijuana congruence for both parents and to cigarette and alcohol congruence for fathers. With the exception of alcohol, older adolescents were significantly more likely to be noncongruent. This was consistent with the developmental hypothesis that older adolescents are more likely to experiment with substances and to be less consistently monitored by their parents. For alcohol, however, there was greater noncongruence for younger adolescents compared to older adolescents. Grade point average (GPA) of the adolescent was significantly and positively related to mother-adolescent (F = 8.10, p < .01) and fatheradolescent (F = 13.26, p < .001) congruency for marijuana, but not cigarettes or alcohol. Race, after-school employment, and gender were found to be unrelated to parent-adolescent congruence for any substance. GPA, reported by only 50% of the adolescents, was significantly and inversely correlated with adolescent self-report of all substances: marijuana use, r = -.25 (p < .01); cigarettes, r = -.37 (p < .01); and alcohol, r = -.25 (p < .01).
Congruence and Perceptions of Family Cohesion and Conflict Because there were low but significant correlations for congruence, conflict, and cohesion scores with adolescent age and parent education, the latter two were employed as covariates in analyses of covariance. The
631
Parent-Adolescent Congruence Table IV. Adolescent Perceived Conflict and Cohesion Ratings by Parent-Adolescent Congruence for Marijuana
Cohesion
Conflict
Congruent
Incongruent
Congruent
Mother
6.21
5.39*
3.65
Incongruent 4.33
Father
6.41
5.37"
3.56
4.39*
"17 < .01.
Table V. Mothers' and Fathers' Mean Perceived Conflict and Cohesion Ratings by Parent-Adolescent Congruence for Marijuana Cohesion Congruent
Incongruent
Conflict Congruent
Incongruent
Mother
3.13
2.91"
2.20
2.35
Father
3.12
2.47**
1.92
2.26**
*p < .05. **p < .001.
adolescent's ratings of family cohesion and conflict were significantly related to father-adolescent (F = 9.15, p < .01, and F = 4.99, p < .05, respectively) and mother-adolescent congruence (F = 7.56, p < .01, and F = 5.85, p < .05, respectively) for marijuana use. The adolescent's cohesion ratings were significantly related to congruence for cigarette smoking with mothers (F = 4.10, p < .05) but marginally so for father (F = 3.02 p < .10). No relationships were found between alcohol congruence and the adolescent's ratings of cohesion or conflict. With the exception of the alcohol data, these findings are consistent with the hypotheses that more cohesive and less conflicted families are likely to have greater congruence regarding adolescents' substance use. Table IV displays the data for the adolescent's conflict and cohesion ratings as they relate to marijuana congruence. Both mothers' (F = 4.13, p < .05) and fathers' (F = 18.3, p < .001) perceptions of family cohesion were significantly related to congruence for marijuana use. Father-adolescent marijuana congruence was also related to the father's perception of family conflict (F = 4.49, p < .05), while the comparable relationship for mothers was marginally significant (F = 3.54, p < .10). No significant relationships were found between mother-adolescent or father-adolescent cigarette or alcohol congruence and parental perceptions of family conflict or cohesion. The data on marijuana congruence and parental ratings of conflict and cohesion are displayed in Table V. It should be noted that the conflict and cohesion subscales were strongly in-
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tercorrelated for adolescents (r = -.58, p < .001) and significantly intercorrelated for mothers (r = -.22, p < .001) and fathers (r = -.27, p < .001).
DISCUSSION
Adolescents' self-reports of substance use were compared to parental perceptions to determine parent-adolescent congruence. One strength of this study was the parallel and simultaneous assessment of adolescents and their parents. This allowed a direct comparison of parents' perceptions of their adolescent's use and the adolescent's self-reported use at that time. The literature in psychiatric diagnosis suggests rough guidelines for evaluating the levels of congruence observed in this study. K a p p a s - and presumably weighted kappas as w e l l - o f the order of >__.75 are considered high, of .4--.75 are good or moderate, and of lower than .4 are seen to reflect poor agreement (Landis and Koch, 1977). By that standard, the weighted kappas obtained in this study suggest that there is moderate agreement between parents and adolescents regarding reported substance use. Only the weighted kappas for alcohol use (.36 mothers, .41 fathers) were below .5. Our data permit us to say very little about frequency of use among users. There were relatively few regular (i.e., daily) users of any substance and we did not obtain systematic frequency estimates from parents and adolescents. It should also be remembered that we assessed congruence between t w o reports of behavior, either of which is subject to bias. The degree of congruence between parents and adolescents was relatively low for alcohol and higher for cigarettes and marijuana. Cigarette congruence may have been increased by the bogus pipeline (Murray et al., 1987), which likely increased accurate reporting by the adolescents. As seen in Table I, marijuana congruence was especially high for never-users. The majority of parents were congruent for two or all three substances, indicating that congruence is fairly consistent across substances. However, one-fourth of the sample was congruent for none or only one substance. These families may be "at risk" for adolescent substance use problems, possibly because of insufficient parent monitoring of their adolescent's behavior. Insufficient monitoring may give adolescents more opportunity to experiment with substances and/or may reflect parental indifference, which indirectly leads to substance use. Further study will be needed to determine if consistent parent-adolescent incongruence is a prospective predictor of adolescent substance abuse. Parent-adolescent congruence was the lowest for alcohol use. This did not support the hypothesis that parents would be the most congruent
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for licit substances and the least congruent for illicit substances such as m a r i j u a n a . I n s t e a d the highest w e i g h t e d k a p p a s w e r e o b t a i n e d for marijuana and the lowest were obtained for alcohol. For cigarettes and marijuana, parents tended to be incongruent because they underestimated their adolescent's reported substance use. However, for alcohol, incongruent mothers and fathers were equally likely to have been over- or underestimating their adolescent's use. Marijuana and cigarette use was determined by a 7-point scale and alcohol use was reported on an 8-point scale. Inspection of the complete congruence matrices (for both mother and father) did not indicate that the additional item--drink only on special occasions with my family--was an important contributor to the pattern of differences between alcohol and marijuana or cigarettes. As indicated by Tables I and II, low congruence on alcohol use was due mostly to parents seeing the adolescent as a usertried once or t w i c e - w h e n the adolescent reported never using. It may be that the easy availability of alcohol and its relative social acceptability combine to make parents think their adolescent must surely have tried it once or twice. The data only partly supported the hypothesis that mothers were more aware of the adolescents' substance use than were fathers; patterns of congruence for the two parents were very similar for smoking and alcohol, but as predicted, fathers were less congruent for marijuana. This difference, however, was not large. Either mothers and fathers are equally likely to be knowledgeable about their adolescent's reported substance use or they may communicate their perceptions to each other. However, single mothers were more likely to be incongruent than were mothers from a two-parent household, supporting the hypothesis that the single mothers may be less able to monitor their adolescent's behavior and would therefore know less about their adolescent's substance use. The adolescent's gender was not significantly related to either m o t h e r adolescent or father-adolescent congruence. Parents were not more likely to attribute less use to girls, thereby underestimating their use as had been predicted. The grade level of the adolescent did significantly relate to mother-adolescent and father-adolescent marijuana congruence and fatheradolescent cigarette congruence. These findings supported the prediction that older adolescents would be more likely to be incongruent with their parents, as they engage in covert activities on a more frequent basis. Alcohol congruence did not conform to this prediction, however. Both m o t h e r - and father-adolescent alcohol incongruence was lower for high school-age adolescents. It is likely that this, again, is a result of parents' tendency to believe that their young adolescent has tried alcohol once or twice while the adolescent reports never using.
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The adolescent's perceptions of family conflict and cohesion were significantly r e l a t e d to b o t h m o t h e r - a d o l e s c e n t and f a t h e r - a d o l e s c e n t cigarette and marijuana congruence but not to congruence for alcohol. Parental perception of family cohesion was especially related to parentadolescent marijuana congruence but not to alcohol or cigarette congruence. Clearly, agreement about adolescent marijuana use had the strongest relationships with family cohesiveness and conflict from both parent and adolescent perspectives. Marijuana, being the only substance studied that is illegal for both parents and adolescents, may serve as a particular focus for poor communication and family discord. These data are also consistent with studies showing that family conflict, including poor parent monitoring, is a precursor to antisocial behavior in youths including substance use (Dishion and Loeber, 1985; Patterson and Bank, 1989). Overall this study has contributed to a description of the degree of disparity between the adolescent's reports of substance use and parental perceptions of the adolescent's use. Our assumption that parent-adolescent congruence with respect to the adolescent's substance use was a meaningful and useful variable was borne out. Parent-adolescent congruence was seen to vary between substances and to relate to the age and GPA of the adolescent. This study also helped to elucidate how adolescents' and parents' perceptions of family functioning related to parent-adolescent congruence. Congruence does appear to be related to important developmental processes. In adolescent substance use studies where it is possible also to assess parents, measures of congruence should be obtained. Further investigation into the meaning of congruence also seems warranted, especially its relationship to parent monitoring. While we focus on the role of parent monitoring for congruence, other explanations should be sought. The cross-sectional nature of the data reported here does not permit drawing causal or directional hypotheses. Prospective research will be needed to evaluate how parent-adolescent congruence changes over time and the relationship of congruence to parental practices and future adolescent substance use.
REFERENCES Andrews, J., Hops, H.,/My, D., Lichtenstein, E., and Tildesley, E. (1990). The construction,
validation, and use of a Guttman scale of adolescent substance use: An investigation of family relationships. J. Drug Issues (in press). Baer, P. E., et at (1985). Stress, coping, family conflict and adolescent alcohol use. Paper presented at the meeting of the Society for Behavioral Medicine, New Orleans, LA, March. Cohen, J. (1968). Nominal scale agreement with provision for scaled disagreement or partial credit. Psychol. Bull. 70: 213-220.
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Dishion, T. J., and Loeber, R. (1985). Adolescent marijuana and alcohol use: The role of parents and peers revisited. Am. J. Drug Alcohol Use 11(1,2): 11-25. Glynn, T. J. (1984). Adolescent drug use and the family environment: A review. J. Drug Use 271-295. Hartup, W. W. (1983). The peer system. In Mussen, P. H. (editor-in-chief), and Hetherington, E. M. (ed.), Carmichael's Manual of Child Psychology, Vol. 4, 4th ed., Wiley, New York, pp. 103-196. Hops, H., Tildesley, E., Lichtenstein, E., Ary, D., and Sherman, S. (1990). Parent-adolescent problem-solving interactions and drug use. Am. J. Drug Alcohol Abuse 16(3,4): 239-258. Krosnick, J. A., and Judd, C. M. (1982). Transitions in social influence at adolescence: Who induces cigarette smoking? Dev. Psychol. 18: 359-368. Landis, J. R., and Koch, G. G. (1977). The measurement of observer agreement for categorical data. Biometrics 33: 159-174. Moos, R. H., and Moos, B. S. (1981). Family Environment Scale Manual, Consulting Psychologists Press, Palo Alto, CA. Murray, D. M., O'Connell, C. M., Schmidt, L. A., and Perry, C. L. (1987). The validity of smoking self-reports by adolescents: A reexamination of the bogus pipeline procedure. Addict. Behav. 12: 7-15. Patterson, G. R., and Bank, L. (1989). In Gunnar, M. R., and Thelen, R. (eds.), Minnesota Symposia on Child Psychology: Systems and Development, Vol. 22, Lawrence Erlbaum Associates, Hillsdale, NJ, pp. 167-209. Patterson, G. R., and Dishion, T. J. (1985). Contributions of families and peers to delinquency. Criminology 23: 63-77. Siegel, S. (1956). Nonparametric Statistics, McGraw-Hill, New York. Steinberg, L. (1986). Latch key children and susceptibility to peer pressure: An ecological analysis. Dev. Psychol. 22: 433-439.
Parent-Adolescent Congruence for Adolescent Substance Use Jennifer Langhinrichsen, 1,3 Edward Lichtenstein, 1,2,4 John R. Seeley, 2 H y m a n Hops, 2 Dennis V. Ary, 2 Elizabeth Tildesley, 2 and Judy Andrews 2 Received March 28, 1989; accepted July 25, 1990
Parental reports of adolescent substance use were compared to the adolescents' self-reports using identical scales. Congruence was defined as exact agreement on whether adolescents were current users, ex-users, or never-users. Both parents were found to be less accurate in predicting their adolescents' alcohol use compared to cigarette or marijuana use. Single mothers were significantly less likely to be congruent than were mothers from two-parent households. Mother and father congruence on all substances was unrelated to the adolescent's sex, race, or after school employment. For both parents, congruence for adolescent marijuana use was significantly related to the age and GPA of the adolescent. Congruence may also reflect important properties of family functioning, as significant relations were found between both adolescent and parent ratings of family cohesion and parent-adolescent congruence on perceptions of marijuana use.
INTRODUCTION Substance use and abuse among youth are ongoing areas of concern for researchers, policy makers, school officials, and parents. The data disThis research was supported by Grant DA03706 from the National Institute of Drug Abuse (Hyman Hops, Principal Investigator). 1University of Oregon. 2Oregon Research Institute. 3jennifer Langhinrichsen is a doctoral candidate in psychology interested in adolescent and family interactions. The other authors are psychologists or data analysts working on family influences on substance use and mental health. aRequests for reprints should be sent to Edward Lichtenstein, Oregon Research Institute, 1899 Willamette, Eugene, Oregon 97401. 623 004%2891/90/1200-0623506.009 1990PlenumPublishingCorporation
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Langhinrichsen et al.
cussed here are part of a larger study that addresses how parental influences affect or interact with adolescents' use of alcohol, tobacco, and marijuana (e.g., Hops et aL, 1990; Andrews et al., 1990). A practical goal of the project is to learn what parents might do or not do to discourage their adolescents from substance use. It is believed that parenting practices are related to adolescent's decisions regarding substance use (Glynn, 1984; Patterson and Dishion, 1985; Dishion and Loeber, 1985). We assume that parental practices with regard to their adolescent's substance use are determined at least partly by their knowledge of the adolescent's user status. Parents who believe their adolescent is smoking or drinking alcohol are likely to behave differently than parents who are unaware of their adolescent's substance use. Parental monitoring, knowing where the adolescent is and what he/she is doing, has been found to be inversely related to antisocial behavior (e.g., Dishion and Loeber, 1985; Steinberg, 1986). Patterson and Bank (1989) have shown that parental monitoring sets the stage for the adolescent's involvement (or acceptance) in the peer group and leads to antisocial behavior. Low levels of monitoring may provide adolescents with greater opportunity to experiment with substances, especially within the peer group setting. It is of interest, therefore, to determine if parents' perceptions of their adolescent's use are accurate. Since accuracy rests on direct knowledge of the adolescents' beh a v i o r - w h i c h is often very difficult to o b t a i n - w e derived a parent-adolescent congruence measure by comparing both parties' reports. Congruence was defined as a match between m o t h e r ' s or father's reports of the adolescent's use of alcohol, cigarettes, and marijuana and the adolescent's self-reported substance use. Both adolescents and parents reported substance use on the same scales. This paper provides descriptive data while examining the impact of a number of theoretically and practically relevant variables on p a r e n t adolescent congruence. First, congruence was examined descriptively by considering frequency, stability across substances, and consistency between parents in the same family. It was hypothesized that there would be greater congruence for licit substances such as cigarettes than for illicit substances such as marijuana because adolescents will tend to be more open with their parents about their use of licit drugs. Alcohol congruence was predicted to be higher than marijuana congruence and lower than cigarette congruence. In terms of consistency between parents in the same family it was hypothesized that mothers would tend to be more congruent with their adolescent than would fathers. This hypothesis was based on the evidence that the mother is the primary parent in terms of adolescent management and monitoring and has better knowledge of her adolescent's behavior
Parent-Adolescent Congruence
625
(Dishion and Loeber, 1985). It was further hypothesized that single mothers would show lower congruence due to their diminished ability to monitor their adolescent's behavior. Second, age, gender, and school achievement were examined in relation to the congruence variable. It was hypothesized that there would be greater congruence for younger adolescents than for older adolescents. Developmentally, it was expected that older adolescents are tending to individuate and separate from their parents (Hartup, 1983) and become more influenced by peers (Krosnick and Judd, 1982). Part of the differentiation process may involve the adolescent's engaging in more covert behaviors and it was expected that these unshared behaviors would reduce congruence. It was also hypothesized that congruence would tend to be higher for boys than for girls on the basis of cultural stereotypes that tend to a t t r i b u t e less use to girls, causing parents to underestimate their daughters' use, which would reduce congruence. Due to the cultural expectation that adolescents who do well in school tend to avoid substance use, it was hypothesized that there would be more incongruence for adolescents with higher GPAs, in keeping with the tendency of these parents to report that their adolescents are nonusers. Third, congruence was examined in relation to parents' and adolescents' self-reported perceptions of family cohesion and conflict. While family conflict is found to be associated with the level of adolescent substance use (e.g., Baer et al., 1985; Hops et aL, 1990), the relationship between conflict and congruence remains unexplored. It was hypothesized that mothers and fathers who rated their home as high in conflict or low in cohesion would be less likely to be congruent with regard to their adolescent's substance use. Likewise, adolescents who rated the home as high in conflict and low in cohesion were expected to be less able to confide in their parents, resulting in decreased congruence.
METHOD
Subjects Adolescents and their families were recruited to participate in a longitudinal study focused on the family's influence on adolescent substance used. Participating families were required to have at least one adolescent between 11 and 15 years of age. The families were recruited from newspaper, television, and radio advertisements in a moderate-sized northwest urban area. There were 763 target adolescents, 390 females and 373 males. The mean age of the target adolescents was 13.2 years, with a range from
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10 to 16.6 years. Seven hundred fifty-eight mothers participated and data were collected from 420 fathers. The N for specific analyses is usually lower because of missing data for one or another variable.
Procedure
All of the adolescents completed a self-report questionnaire assessing the extent of their substance use. Parents accompanied the adolescents to the assessment and simultaneously, but in a separate location, filled out a questionnaire that was parallel in nature. There was concern that adolescents might underreport their substance use in a setting where their parents were also being assessed. Two safeguards were employed to increase the validity of the adolescents' responses. First, all subjects were assured of the confidentiality of their responses. Second, with regard to cigarette smoking, each adolescent provided an expired air sample, which he or she was told would provide objective information about his or her smoking status. This bogus pipeline procedure has been found to increase the accuracy of adolescent reports of their tobacco use (Murray et al., 1987). It was hoped that this increased accuracy would generalize to the adolescents' reports of other substance use. Each family was paid $35 for the completion of the assessment.
Measures
Substance Use. Adolescents indicated their lifetime use of cigarettes, alcohol, and marijuana by checking the most applicable category on a 7point (cigarettes, marijuana) or 8-point (alcohol) rating scale. Potential responses ranged from "I have never smoked cigarettes, not even once" to "I smoke cigarettes at least once per day." The additional alcohol item was "drink only on special occasions with my family." For the purposes of this study, adolescents' responses were collapsed into three categories: (a) those who had never used the substance, (b) those who had used the substance in the past but were not current users, and (c) those who were currently using the substance (which included "special-occasion" users of alcohol). Each parent completed a parallel scale with which to describe his or her teen's substance use. Parental responses were collapsed into the same three categories. Congruence. Congruence was defined as exact agreement between parent and adolescent using the collapsed three categories. Degree of congruence was assessed via weighted kappa (Cohen, 1968). The kappa weights
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were determined a priori; weights of 1 and 2 were assigned to pairs off by one and two categories, respectively. Demographic Factors. D e m o g r a p h i c data collected i n c l u d e d the adolescents' age, sex, race, grade, grade point average, and after-school work history and the parents' marital status, education, and gender. Family Relations. Perceptions of cohesion and conflict were assessed for both parents and adolescent via the cohesion and conflict subscales of the Family Environment Scale (FES; Moos, 1981). Each FES subscale consisted of nine items which were presented in a true/false format. The conflict subscale was designed to measure family members' perceptions of the degree to which open expressions of anger and aggression are characteristic of the family. The cohesion subscale was designed to measure the extent to which family members are thought to be involved with, supportive of, and helpful to one another.
RESULTS
Degree of Congruence The perceptions of 70% of the sampled mothers were congruent (exact agreement) with their adolescent's reported cigarette use and 78% were congruent with marijuana use. Only 54% of the mothers correctly identified their adolescent's alcohol-use status. The corresponding values for father-adolescent agreement were 70, 80, and 55%, respectively. While the values for mothers and fathers are similar, a test of the hypothesis that mothers would be more congruent than fathers requires a comparison of parents from the same household. Therefore, the congruence of mothers and fathers from the same households was compared for each substance using the McNemar test for related samples (Siegel, 1956). No differences between mothers and fathers were found for smoking (~2 = .57, n.s.) and alcohol (2z = .9, n.s.) but significant differences were found for marijuana (2a = 6.6, p < .05). More fathers (20.6%) than mothers (16.5%) were incongruent for marijuana. Table I presents parent-adolescent agreement by the level of the adolescent's reported use. It can be seen that, for cigarettes and marijuana, congruence is highest for nonusing adolescents, but for alcohol, congruence is lowest for nonusers. Weighted kappa was used as chance-corrected measure of agreement to quantify parent-adolescent congruence. For mothers and adolescents, weighted kappas were .36 for alcohol, .59 for cigarettes, and .61 for marijuana. For fathers, the corresponding values were .41, .54, and .56. All
Alcohol Cigarettes Marijuana
(n = 726) (n = 734) (n = 727)
.39 .85 .92
Never-users .66 .61 .59
Ex-users .52 .54 .41
Current users
Mother-adolescent congruence
(n = 418) (n = 420) (n = 417)
.51 .89 .94
Never-users
.60 .47 .43
Ex-users
Father-adolescent congruence
.54 .52 .42
Current users
Table I. Percentage of Congruent (Exact-Agreement) Parent-Adolescent Pairs by Level of Adolescent's Use
t~
~r
0~
t,O O0
Parent-Adolescent Congruence
629
values are highly significant (p < .001). Consistent with the percentage agreement data, for both parents, the highest weighted kappas were obtained for the adolescent's marijuana use and the lowest amount of agreement was obtained for alcohol use. This did not support the prediction that congruence would be greater for licit drugs than for illicit drugs such as marijuana. As shown in Table II, the majority of incongruent mothers and fathers significantly underestimated, rather than overestimated, their adolescent's reported use of marijuana and cigarettes. However, incongruent parents were about equally likely to over- or underestimate the drinking behavior of their adolescent. The consistency of parent-adolescent congruence across substances was assessed by examining the number of mother-adolescent and father-adolescent pairs congruent for all three substances, any two, any one, or none. Mothers and fathers were equally consistent across substances. Approximately 35% of parents were congruent for all three substances, 39% were congruent for any two, and only 7% were not congruent for any substance.
Congruence, Age, Sex, and School Achievement Single mothers were significantly more likely to be incongruent with their adolescent's reports of substance use for any one, two, or all three substances than were mothers from two-parent households (Z2 = 7.8, p < .05). Adolescents' grade level was split to compare those in the ninth grade and above (high school) with those in the eighth grade and below (middle school), although about three-fourths of the adolescents were in middle schools. As shown in Table III, grade level was significantly related to
Table II. Percentage of Parents who Over- and Underestimate Their Adolescent's Self-Reported Substance Use ~ overestimating %underestimating Alcohol Mothers (n = 726) 24.2 21.6 Fathers (n = 418) 22.7 22.0 Marijuana Mothers (n = 727) 6.6 15.8" Fathers (n = 417 5.3 14.9" Cigarettes Mothers (n = 734) 8.4 20.1" Fathers (n = 420) 6.7 23.1" ap < .001, difference in proportion between overestimaters and underestimaters.
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Langhinrichsen et al. Table I!1. Percentage of Parent-Adolescent Noncongruence by Substance and Adolescent's Grade Level Cigarettes Mother Father Alcohol Mother Father Marijuana Mother Father
~ 8 t h grade
~ 9 t h grade
29070 (n = 148) 25070 (n = 78)
31% (n = 69) 4207o** (n = 47)
48% (n = 243) 48% (n = 146)
41% (n = 90) 37%* (n = 41)
19070 (n = 94) 17070 (n = 51)
33%** 69) 30%** (n = 33)
*p < .05. **p < .001.
marijuana congruence for both parents and to cigarette and alcohol congruence for fathers. With the exception of alcohol, older adolescents were significantly more likely to be noncongruent. This was consistent with the developmental hypothesis that older adolescents are more likely to experiment with substances and to be less consistently monitored by their parents. For alcohol, however, there was greater noncongruence for younger adolescents compared to older adolescents. Grade point average (GPA) of the adolescent was significantly and positively related to mother-adolescent (F = 8.10, p < .01) and fatheradolescent (F = 13.26, p < .001) congruency for marijuana, but not cigarettes or alcohol. Race, after-school employment, and gender were found to be unrelated to parent-adolescent congruence for any substance. GPA, reported by only 50% of the adolescents, was significantly and inversely correlated with adolescent self-report of all substances: marijuana use, r = -.25 (p < .01); cigarettes, r = -.37 (p < .01); and alcohol, r = -.25 (p < .01).
Congruence and Perceptions of Family Cohesion and Conflict Because there were low but significant correlations for congruence, conflict, and cohesion scores with adolescent age and parent education, the latter two were employed as covariates in analyses of covariance. The
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Parent-Adolescent Congruence Table IV. Adolescent Perceived Conflict and Cohesion Ratings by Parent-Adolescent Congruence for Marijuana
Cohesion
Conflict
Congruent
Incongruent
Congruent
Mother
6.21
5.39*
3.65
Incongruent 4.33
Father
6.41
5.37"
3.56
4.39*
"17 < .01.
Table V. Mothers' and Fathers' Mean Perceived Conflict and Cohesion Ratings by Parent-Adolescent Congruence for Marijuana Cohesion Congruent
Incongruent
Conflict Congruent
Incongruent
Mother
3.13
2.91"
2.20
2.35
Father
3.12
2.47**
1.92
2.26**
*p < .05. **p < .001.
adolescent's ratings of family cohesion and conflict were significantly related to father-adolescent (F = 9.15, p < .01, and F = 4.99, p < .05, respectively) and mother-adolescent congruence (F = 7.56, p < .01, and F = 5.85, p < .05, respectively) for marijuana use. The adolescent's cohesion ratings were significantly related to congruence for cigarette smoking with mothers (F = 4.10, p < .05) but marginally so for father (F = 3.02 p < .10). No relationships were found between alcohol congruence and the adolescent's ratings of cohesion or conflict. With the exception of the alcohol data, these findings are consistent with the hypotheses that more cohesive and less conflicted families are likely to have greater congruence regarding adolescents' substance use. Table IV displays the data for the adolescent's conflict and cohesion ratings as they relate to marijuana congruence. Both mothers' (F = 4.13, p < .05) and fathers' (F = 18.3, p < .001) perceptions of family cohesion were significantly related to congruence for marijuana use. Father-adolescent marijuana congruence was also related to the father's perception of family conflict (F = 4.49, p < .05), while the comparable relationship for mothers was marginally significant (F = 3.54, p < .10). No significant relationships were found between mother-adolescent or father-adolescent cigarette or alcohol congruence and parental perceptions of family conflict or cohesion. The data on marijuana congruence and parental ratings of conflict and cohesion are displayed in Table V. It should be noted that the conflict and cohesion subscales were strongly in-
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tercorrelated for adolescents (r = -.58, p < .001) and significantly intercorrelated for mothers (r = -.22, p < .001) and fathers (r = -.27, p < .001).
DISCUSSION
Adolescents' self-reports of substance use were compared to parental perceptions to determine parent-adolescent congruence. One strength of this study was the parallel and simultaneous assessment of adolescents and their parents. This allowed a direct comparison of parents' perceptions of their adolescent's use and the adolescent's self-reported use at that time. The literature in psychiatric diagnosis suggests rough guidelines for evaluating the levels of congruence observed in this study. K a p p a s - and presumably weighted kappas as w e l l - o f the order of >__.75 are considered high, of .4--.75 are good or moderate, and of lower than .4 are seen to reflect poor agreement (Landis and Koch, 1977). By that standard, the weighted kappas obtained in this study suggest that there is moderate agreement between parents and adolescents regarding reported substance use. Only the weighted kappas for alcohol use (.36 mothers, .41 fathers) were below .5. Our data permit us to say very little about frequency of use among users. There were relatively few regular (i.e., daily) users of any substance and we did not obtain systematic frequency estimates from parents and adolescents. It should also be remembered that we assessed congruence between t w o reports of behavior, either of which is subject to bias. The degree of congruence between parents and adolescents was relatively low for alcohol and higher for cigarettes and marijuana. Cigarette congruence may have been increased by the bogus pipeline (Murray et al., 1987), which likely increased accurate reporting by the adolescents. As seen in Table I, marijuana congruence was especially high for never-users. The majority of parents were congruent for two or all three substances, indicating that congruence is fairly consistent across substances. However, one-fourth of the sample was congruent for none or only one substance. These families may be "at risk" for adolescent substance use problems, possibly because of insufficient parent monitoring of their adolescent's behavior. Insufficient monitoring may give adolescents more opportunity to experiment with substances and/or may reflect parental indifference, which indirectly leads to substance use. Further study will be needed to determine if consistent parent-adolescent incongruence is a prospective predictor of adolescent substance abuse. Parent-adolescent congruence was the lowest for alcohol use. This did not support the hypothesis that parents would be the most congruent
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for licit substances and the least congruent for illicit substances such as m a r i j u a n a . I n s t e a d the highest w e i g h t e d k a p p a s w e r e o b t a i n e d for marijuana and the lowest were obtained for alcohol. For cigarettes and marijuana, parents tended to be incongruent because they underestimated their adolescent's reported substance use. However, for alcohol, incongruent mothers and fathers were equally likely to have been over- or underestimating their adolescent's use. Marijuana and cigarette use was determined by a 7-point scale and alcohol use was reported on an 8-point scale. Inspection of the complete congruence matrices (for both mother and father) did not indicate that the additional item--drink only on special occasions with my family--was an important contributor to the pattern of differences between alcohol and marijuana or cigarettes. As indicated by Tables I and II, low congruence on alcohol use was due mostly to parents seeing the adolescent as a usertried once or t w i c e - w h e n the adolescent reported never using. It may be that the easy availability of alcohol and its relative social acceptability combine to make parents think their adolescent must surely have tried it once or twice. The data only partly supported the hypothesis that mothers were more aware of the adolescents' substance use than were fathers; patterns of congruence for the two parents were very similar for smoking and alcohol, but as predicted, fathers were less congruent for marijuana. This difference, however, was not large. Either mothers and fathers are equally likely to be knowledgeable about their adolescent's reported substance use or they may communicate their perceptions to each other. However, single mothers were more likely to be incongruent than were mothers from a two-parent household, supporting the hypothesis that the single mothers may be less able to monitor their adolescent's behavior and would therefore know less about their adolescent's substance use. The adolescent's gender was not significantly related to either m o t h e r adolescent or father-adolescent congruence. Parents were not more likely to attribute less use to girls, thereby underestimating their use as had been predicted. The grade level of the adolescent did significantly relate to mother-adolescent and father-adolescent marijuana congruence and fatheradolescent cigarette congruence. These findings supported the prediction that older adolescents would be more likely to be incongruent with their parents, as they engage in covert activities on a more frequent basis. Alcohol congruence did not conform to this prediction, however. Both m o t h e r - and father-adolescent alcohol incongruence was lower for high school-age adolescents. It is likely that this, again, is a result of parents' tendency to believe that their young adolescent has tried alcohol once or twice while the adolescent reports never using.
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The adolescent's perceptions of family conflict and cohesion were significantly r e l a t e d to b o t h m o t h e r - a d o l e s c e n t and f a t h e r - a d o l e s c e n t cigarette and marijuana congruence but not to congruence for alcohol. Parental perception of family cohesion was especially related to parentadolescent marijuana congruence but not to alcohol or cigarette congruence. Clearly, agreement about adolescent marijuana use had the strongest relationships with family cohesiveness and conflict from both parent and adolescent perspectives. Marijuana, being the only substance studied that is illegal for both parents and adolescents, may serve as a particular focus for poor communication and family discord. These data are also consistent with studies showing that family conflict, including poor parent monitoring, is a precursor to antisocial behavior in youths including substance use (Dishion and Loeber, 1985; Patterson and Bank, 1989). Overall this study has contributed to a description of the degree of disparity between the adolescent's reports of substance use and parental perceptions of the adolescent's use. Our assumption that parent-adolescent congruence with respect to the adolescent's substance use was a meaningful and useful variable was borne out. Parent-adolescent congruence was seen to vary between substances and to relate to the age and GPA of the adolescent. This study also helped to elucidate how adolescents' and parents' perceptions of family functioning related to parent-adolescent congruence. Congruence does appear to be related to important developmental processes. In adolescent substance use studies where it is possible also to assess parents, measures of congruence should be obtained. Further investigation into the meaning of congruence also seems warranted, especially its relationship to parent monitoring. While we focus on the role of parent monitoring for congruence, other explanations should be sought. The cross-sectional nature of the data reported here does not permit drawing causal or directional hypotheses. Prospective research will be needed to evaluate how parent-adolescent congruence changes over time and the relationship of congruence to parental practices and future adolescent substance use.
REFERENCES Andrews, J., Hops, H.,/My, D., Lichtenstein, E., and Tildesley, E. (1990). The construction,
validation, and use of a Guttman scale of adolescent substance use: An investigation of family relationships. J. Drug Issues (in press). Baer, P. E., et at (1985). Stress, coping, family conflict and adolescent alcohol use. Paper presented at the meeting of the Society for Behavioral Medicine, New Orleans, LA, March. Cohen, J. (1968). Nominal scale agreement with provision for scaled disagreement or partial credit. Psychol. Bull. 70: 213-220.
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Dishion, T. J., and Loeber, R. (1985). Adolescent marijuana and alcohol use: The role of parents and peers revisited. Am. J. Drug Alcohol Use 11(1,2): 11-25. Glynn, T. J. (1984). Adolescent drug use and the family environment: A review. J. Drug Use 271-295. Hartup, W. W. (1983). The peer system. In Mussen, P. H. (editor-in-chief), and Hetherington, E. M. (ed.), Carmichael's Manual of Child Psychology, Vol. 4, 4th ed., Wiley, New York, pp. 103-196. Hops, H., Tildesley, E., Lichtenstein, E., Ary, D., and Sherman, S. (1990). Parent-adolescent problem-solving interactions and drug use. Am. J. Drug Alcohol Abuse 16(3,4): 239-258. Krosnick, J. A., and Judd, C. M. (1982). Transitions in social influence at adolescence: Who induces cigarette smoking? Dev. Psychol. 18: 359-368. Landis, J. R., and Koch, G. G. (1977). The measurement of observer agreement for categorical data. Biometrics 33: 159-174. Moos, R. H., and Moos, B. S. (1981). Family Environment Scale Manual, Consulting Psychologists Press, Palo Alto, CA. Murray, D. M., O'Connell, C. M., Schmidt, L. A., and Perry, C. L. (1987). The validity of smoking self-reports by adolescents: A reexamination of the bogus pipeline procedure. Addict. Behav. 12: 7-15. Patterson, G. R., and Bank, L. (1989). In Gunnar, M. R., and Thelen, R. (eds.), Minnesota Symposia on Child Psychology: Systems and Development, Vol. 22, Lawrence Erlbaum Associates, Hillsdale, NJ, pp. 167-209. Patterson, G. R., and Dishion, T. J. (1985). Contributions of families and peers to delinquency. Criminology 23: 63-77. Siegel, S. (1956). Nonparametric Statistics, McGraw-Hill, New York. Steinberg, L. (1986). Latch key children and susceptibility to peer pressure: An ecological analysis. Dev. Psychol. 22: 433-439.
