The overall goal of the proposed research is to investigate ethnic identity in early-to-middle adolescence. The methodologic aim is to develop measures to assess important dimensions of ethnic identity researchers have identified. Among these are: (1) Ethnic self-identification; (2) ethnic constancy; (3) ethnic role behaviors; (4) ethnic knowledge; and (5) ethnic preferences and feelings. Other dimensions include stages of ethnic identity formation such as unexamined, exploration, and achieved. The descriptive aim is to document the prevalence or distribution of dimensions of ethnic identity in relevant social status subgroups, and how these dimensions of ethnic identity change or do not change over time. The analytic focus in on the social and psychological correlates of ethnic identity. We will examine the predictors of change in ethnic identity and the effects of change in ethnic identity on other aspects of the lives of adolescents, including socioemotional adjustment (mental health). Subjects will be assessed three times (annually) over a 24-month period. Data will be acquired using four procedures: (1) A series of focus groups will be used to develop and refine the measures of ethnic identity. (2) A self-administered questionnaire will be used to collect data for the proposed study of ethnic identity. (3) Selected data on ethnic identifiers, grades, socioeconomic statue, and standardized toot scores from school records will be linked to the survey data. (4) A mail survey of a sample of parents will collect data on ethnic identity and socioeconomic status from the parents. Using selected items on health and functioning from the adolescent questionnaire, parents also will be asked to report about their children. The T1 sample of adolescents will be 4,400 (1,800 Anglos, 2,600 Mexican origin) and the T1 sample of parents will be 1,646 (715 Anglo, 931 Mexican Origin). The unifying construct is ethnic identity, feelings, attitude, knowledge, and behaviors about one's ethnicity. Other constructs include social placement variables such an age, gender, socioeconomic status, family composition, etc., stressors such as discrimination, life events, financial strain, role strain, and poor school performance, and psychosocial resources such as self-esteem, coping, mastery, optimism, competence, and social support. The basic premise is that ethnic identity impacts mental health primarily by increasing stressors and/or decreasing resources. Mental health variables include depression, anxiety, suicide ideation, and substance use. Data analyses focus on: (1) Analysis of trends in indicators of ethnic identity and mental health across three observation periods (T1, T2, T3), (2) the relationship, over time, between ethnic identity, other status attributes, resources, stressors, and indicators of adolescent mental health; and (3) analyses of reliability, stability, and dimensionality of the measures of ethnic identity and other constructs.