Rasch modeling of the structure of health risk behavior in South african adolescents.

The study used Rasch analysis to investigate the presence of a syndrome of health risk behavior in South African adolescents. A total of 2186 in-school adolescents participated in the study (males = 1077; females = 1119; age range = 12-16 years; median = 13 years). The data are baseline from a longitudinal study of a leisure-based drug abuse and HIV/AIDS prevention program at Mitchell's Plain in Cape Town, South Africa. The adolescents completed a self-report measure on various health risk vulnerabilities, including use of alcohol, tobacco and other drugs (ATOD), co-occurrence of penetrative sex with use of ATOD, health related self-efficacy, personal beliefs about health, peer perceptions, and use of contraceptives. The Rasch analysis calibrated data on 50 items from the aforesaid conceptually distinct health risk domains. Infit and Outfit mean square statistics and principal components analysis of the standardized residuals suggested a fit of the data to the unidimensional Rasch measurement model. The findings support a syndrome view of health risk in teenagers as proposed by problem behavior theory.