Purpose: To present a set of multi-item indicators and associated reliability 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 behaviors of a nationally representative sample of U.S. adolescents, as well as on individual-level and contextual factors that either promote young peoples' health or increase their health risk. Specifically, the 135-page in-home adolescent survey instrument includes multiple items intended to measure individual-level and social-environmental constructs relevant to adolescent 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 data. These steps include identification of inconsistent responders, use of a split-halves approach to measurement validation, and use of a deductive approach 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 across grade, gender, and race/ethnic groups included in this nationally representative sample of adolescents. In addition, moderate to high bivariate correlations 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.