Evaluating AIDS Prevention Interventions Using Behavioral and Biological Outcome Measures

Objective: To begin a dialogue on the role of behavioral and biological outcome measures in evaluating the effectiveness of behavior change interventions to reduce the risk of transmitting and acquiring HIV and other sexually transmitted diseases (STDs).

Methods: A selective review of the literature was undertaken to identify issues and problems associated with the use of behavioral and biological outcome measures. In particular, the article considers the validity of self-reports and the theoretical relationships between behavioral and biological measures.

Results: Available data suggest that when proper care is taken, behavioral self-reports are valid. Similarly, sensitive and specific diagnostic tests are available, particularly for bacterial STDs. However, even when diagnostic tests and behavioral self-reports provide valid data, one should not expect a simple relationship between behavioral and biological measures.

Conclusion: Both behavioral and biological measures are important outcomes for studying the efficacy and effectiveness of behavior-change interventions. However, one measure cannot substitute for or validate the other, and neither serves as a true surrogate for HIV prevalence or incidence. Therefore, it is important to better understand the relationship among STDs, HIV, and self-reported condom use. To do this, it will first be necessary to assess correct as well as consistent condom use.