A comparison of three daily coital diary designs and a phone-in regimen

Barrier contraceptive trials and disease intervention studies often utilize coital diaries to measure sexual exposures: dates and frequency of intercourse, product use, additional or alternative contraceptive use, and menstrual bleeding. The validity of these self-reported data is a matter of debate, but if used, better diary designs are sought. We studied 3 different coital diaries, plus a phone-in regimen (none or weekly) in a 3 x 2 factorial design to compare participant ratings and promptness of recording. Our underlying presumption was that ease of and satisfaction with use, and promptness of data collection, are associated with greater accuracy. A self-completed questionnaire at the end of the study collected comparative retrospective data. Diary 1 captured information about a single day on one page and had three columns, for up to three possible acts of intercourse. Diary 2 had the same question format as the first diary, but contained 7 days per page. Diary 3 had 7 days on a page, but instead of a column for each act, participants enumerated the number of acts, the types of contraception used, and condom use details. Half of the women in each diary group phoned in their data weekly. Phone-in improved participants' satisfaction with the diary design as reflected by higher ratings of diary features. Phone-in did not improve recall of data at the end of the study for any of the diaries. There were no differences in the promptness of diary completion. Diaries 1 and 2 showed good concordance with recalled data, and participants expressed a preference for the layout of Diary 2. Women assigned to Diary 3 expressed dissatisfaction with the design and were worse at recalling data at the end of the study, probably due to the complexity of that diary design.