Consistency of Adolescent Self-Report of Age at First Engagement in Five Sexual Behaviors.

Self-report data are integral to sexuality research, yet their reliability is often questioned. We leveraged a cohort study of adolescents aged 13-17 years and living in the United States (recruited 2022-2023) to evaluate the consistency of self-reported sexual behavior initiation. Participants were surveyed at baseline, 4-, 9-, and 15-month follow-ups. Eligible participants completed at least two surveys (n = 1,300). At each timepoint, participants reported the age they first consensually engaged, if ever, in: penetration of the vagina or anus with fingers (digital penetration), oral sex, sex with a toy, penile-vaginal sex, and penile-anal sex. We assigned response patterns as consistent or inconsistent over follow-up. To evaluate whether reports more proximal to the age of initiation were more consistent, we evaluated the proportion of inconsistent responses stratified by whether first engagement was prior to versus during study follow-up. Consistency was high: 81-94%, depending on the type of sex. Nineteen percent of participants had inconsistent reports for digital penetration versus 15% for oral sex, 12% for penetration with toys, 9% for penile-vaginal sex, and 6% for penile-anal sex. Reports collected more proximal to initiation were more consistent. In a diverse cohort of adolescents, we report high consistency of self-report data. Initiating data collection prior to first sex may improve consistency.