Development of adolescent self-report measures from the national longitudinal study of adolescent health

Purpose: To present a set of multi-item indicators and associated reliabili ty estimates derived from early research with survey data from adolescents participating in the National Longitudinal Study of Adolescent Health (Add Health). Methods: Add Health provides information on the health and health-related b ehaviors of a nationally representative sample of U.S. adolescents, as well as on individual-level and contextual factors that either promote young pe oples' health or increase their health risk. Specifically, the 135-page in- home adolescent survey instrument includes multiple items intended to measu re individual-level and social-environmental constructs relevant to adolesc ent health and well-being. This article details the development of a set of multi-item scales and indices from Add Health in-home adolescent survey da ta. These steps include identification of inconsistent responders, use of a split-halves approach to measurement validation, and use of a deductive ap proach in the development of scales and item composites. Results: Estimates of internal consistency reliability suggest that many of the multi-item measures have acceptable levels of internal consistency acr oss grade, gender, and race/ethnic groups included in this nationally repre sentative sample of adolescents. In addition, moderate to high bivariate co rrelations between selected measures provide initial evidence of underlying latent constructs. Conclusions: This article provides adolescent health researchers with a set of methodologic procedures and measures developed in early research on the Add Health core adolescent data set. (C) Society for Adolescent Medicine, 2000.