We evaluated their risk behaviors as well as their knowledge of HIV and other sexually transmitted diseases, but we weren't allowed to ask them if they were HIV-positive. For the probationers study, however, we could collect that information. RTI researchers have long history of asking people about these topics. You have to ask these questions in the right way to get an accurate response. Different socio-demographic groups define sexual activity differently.
Adolescents use different terminology from adults.
And some groups tend to deny that they're engaging in certain behaviors. Our understanding of such factors allows RTI researchers to design survey instruments that get more accurate information.