MORISKY, ANG, AND SNEED SOCIAL DESIRABILITY VALIDATING THE EFFECTS OF SOCIAL DESIRABILITY ON SELF-REPORTED CONDOM USE BEHAVIOR AMONG COMMERCIAL SEX WORKERS Donald E. Morisky, Alfonso Ang, and Carl D. Sneed Most studies on the transmission of HIV depend upon self-reports of risky be- haviors. This study examines if there is social desirability bias with respect to self-reported condom use behavior, assesses the reliability of a self-reported con- dom use scale, and validates the self-reported findings with clinical sexually transmitted infection (STI) diagnosis for commercial sex workers (N = 1,383) in the Philippines. The reliability of the condom use scale is .81, and results from confirmatory factor analysis indicate that the data fit the model well. Sex work- ers who reported using condoms consistently had significantly lower rates of sex- ually transmitted infections compared to those who never used a condom (t = 7.79, p < .01). It was concluded that no social desirability bias existed with the self-reported condom use scale. Furthermore, the condom use measure was found to have a high level of concurrent validity with STI outcomes. There is a tendency for individuals to avoid negative evaluations and portray a posi- tive view of themselves by providing self-reports of behaviors that are socially desir- able (Latkin, 1998; Loo & Thorpe, 2000). The accuracy of epidemiological studies on the transmission of HIV through various forms of sexual contact often depends upon self-reports of precautions taken during risky sexual behavior. The stigma associated with certain risky sexual behaviors as well as other behaviors associated with the transmission of HIV (e.g., multiple sex partners, commercial sex work, intravenous drug use) may further complicate issues regarding self-reports (Brody, 1995). To check for the potential presence of self-presentation bias, it is important for researchers to validate measures based on self-reports. The objectives of this study are to examine if there is social desirability bias with respect to self-reported condom use behavior, to assesses the reliability of a self-reported condom use scale, and to validate the self-reported findings with clinical sexually transmitted infection (STI) diagnosis for commercial sex workers in the Philippines. AIDS Education and Prevention, 14(5), 351–360, 2002 © 2002 The Guilford Press 351 Donald E. Morisky, Alfonso Ang, and Carl D. Sneed are with the University of California, Los Angeles. The authors extend appreciation to coinvestigators Drs. Teodora Tiglao, Sandra Tempongko, and Jane Baltazar; site coordinators Dorcas Romen, Mildred Publico, Angie Casas, and Lolipel Gella, and research manager Daisy Mejilla. They also thank Consepcion Sanchez for her helpful editorial comments on earlier drafts of this article and Kenn Liu for data management. This research was supported by Grant R01-AI33845A from the National Institutes of Allergy and Infectious Diseases to Donald E. Morisky. Address correspondence to Donald E. Morisky, Sc.D., MSPH, Department of Community Health Sciences, UCLA School of Public Health, Box 951772, Los Angeles, CA 90095-1772; E-mail: dmorisky@ucla.edu