Repeatability of interview-derived information on sexual history: a study in women.

We assessed the repeatability of interview-derived information on age at first sexual intercourse and number of sexual partners in women participating in an ongoing prospective study of genital human papillomavirus infection in Toronto, Canada. Of the 100 study participants invited to attend for re-interview twice during their first year in the study, 74 attended for the first follow-up interview about 5 months after recruitment, and 28 of these 74 subjects attended for a second interview about 4 months later. For both age at first sexual intercourse and number of sexual partners, intraclass correlation coefficients were high, ranging from 0.94 to 0.98. Repeatability differed a little by human papillomavirus status, but not by levels of other relevant factors.