Development and test-retest reliability of a research instrument designed to evaluate school-based HIV/AIDS interventions in South Africa and Tanzania

Aims: This article reports on the development and psychometric properties of an instrument to evaluate school-based HIV/AIDS interventions aimed at adolescents in three African sites. Methods: The instrument was developed in a series of steps that involved a review of existing instruments; use of empirical data and secondary literature supporting an association between the variables of interest and sexual intercourse or condom use; operationalizing the constructs of the theoretical model employed; and using the objectives of the intervention. Test-retest reliability studies were conducted at each site. Results: The questionnaire demonstrated good internal consistency and adequate test-retest reliability. Cronbach's alpha was higher than 0.50 for all the 10 psychosocial scales, while Cohen's kappa showed poor to substantial test-retest reliability on the sexual behaviour items (kappa = 0.14 to 0.69). Conclusions: We conclude that the instrument had sufficient test-retest reliability and internal consistency.