Reliability of adolescents' self-reported sexual behavior: a comparison of two diary methodologies.

PURPOSE: To evaluate techniques for measuring high-risk sexual behaviors by comparing the reliability and acceptability of two daily sexual behavior diary modes: a written calendar and an automated telephone interview. METHODS: This randomized controlled study included 105 sexually active female adolescents aged 15-19 years recruited from among teens seeking reproductive health care services at a family planning clinic in the San Francisco Bay Area. Participants completed a standardized sexual behavior questionnaire each day for 4 weeks. Contraceptive use by method type was recorded. Reporting differences between the two diary modes were assessed using generalized estimating equations, concordance of diary and retrospective interview responses was evaluated using kappa statistics, and contingency table analysis and Poisson regression models were constructed to examine mode acceptability. RESULTS: Respondents randomized to the telephone diary cohort reported less frequent use of barrier contraceptive methods, specifically less spermicide use (odds ratio 0.27, 95% confidence interval 0.08, 0.95), and decreasing male condom use over time, whereas reports of male condom use increased for written diary respondents (p = .007). Participant characteristics associated with diary acceptability, defined as the frequency of diary completion, were assessed and teens classified as higher risk provided fewer diary reports (p < .01). Regardless of mode completed, 65% of respondents believed the telephone diary would be preferable to the written diary for most teens. CONCLUSIONS: The automated telephone diary offered an acceptable, even preferred, methodologic alternative to the written diary calendar and elicited more accurate reporting of selected contraceptive behavior.