AIDS knowledge and attitudes among injection drug users: the issue of reliability.

Among injection drug users (IDUs), AIDS-related knowledge and attitudes have not consistently predicted AIDS risk behavior. This may be due in part to the limited reliability of indexes used to measure drug users' AIDS knowledge and attitudes. In addition, the substantive interpretation of findings is confounded if index reliability is lower for particular demographic groups (e.g., ethnic populations and women). This report is based on 8 measures of AIDS-related knowledge and attitudes in a sample of 332 injection drug users in Los Angeles. The reliability of knowledge and attitude indexes for the overall sample is generally acceptable for the purpose of group comparison (average alpha = .60). But reliability is consistently lower for respondents who are Hispanic (average alpha = .49) and respondents with less formal education (alpha = .56). The reliability of 2 measures of sex-related attitudes is lower for female respondents. It is therefore important that the reliability of knowledge and attitude indexes be assessed not just for drug-user samples as a whole, but also within demographic groups of substantive interest.