Prevention of cognitive and interpersonal problems requires: (1) the identification of causal factors that are the primary contributors to adolescent incompetence and (2) the identification of those variables, causal or mediating, which can be the best targets of intervention. Developmental problems in early adolescence are the best predictors of problems of adult adjustment which require costly treatment programs. Prior studies have looked for singular causes in either the child or the environment. The proposed study will evaluate the relative contributions of characteristics of the child, the child's family and the environmental context to cognitive and social functioning in early adolescence. A sample of about 180 13-year-olds will be assessed with measures of social, intellectural, and scholastic competence. Their families will be assessed for mental health, social competence, child development perspectives, social support networks, and coping abilities. The environmental context will be evaluated for stressful life events, social support networks and demographic characteristics. In addition to actual competence of the child, his personal attributes, his peer support network, his perception of his competence, perceived locus of control and physical attractiveness will be measured as possible mediating variables. These mediating variables are more modifiable than many of the major causal variables in the environment. Data on child competence, family functioning, and environmental factors collected in a previous study of these children from birth to four years of age will be compared with current family and environmental assessments for prediction of 13-year child competence using multivariate statistical techniques. Structural equation models will be used to evaluate the potential of early intervention with children, family, or the environment in reducing developmental problems in adolescence. Results are expected to inform prevention researchers about the sequence of factors mediating the cognitive and social competence and incompetence.