Reliability of self-reported sexual histories: Test-retest and interpartner comparison in a sexually transmitted diseases clinic

Background and Objectives: The objective was to assess reliability of self-reported sexual histories among sexually transmitted disease clinic attendees who enrolled in a study in 1994. Goal of this Study: Knowledge about the reliability of sexual data is important to decide whether these measures of sexual behavior can be used in epidemiologic studies of sexually transmitted diseases. Study Design: In 288 attendees, degree of agreement was assessed in responses to an identical set of sexual questions asked independently by a medical doctor and a public health nurse and in responses made by members of the same couple (n = 50) to a public health nurse. Results: In the test-retest comparison, high agreement was found for most questions: kappa-values and exact agreement ranged from 0.73 to 0.96 and 54% to 99%, respectively. Participants interviewed by the medical doctor reported significantly lower numbers of partners and a higher age at first intercourse. Stratified analyses showed variability in agreement across subgroups. Most consistent, women provided more reliable reports than men. In the comparison of couples, substantial agreement was found for the municipality where they met (88% agreement; kappa = 0.72) and contraceptive method (87% agreement; kappa = 0.60), but only moderate agreement was found for frequency of sexual intercourse (26% agreement; kappa = 0.50). Conclusion: The authors conclude that data on sexual behavior can be collected reliably among sexually transmitted disease clinic attendees, although reporting bias does occur. The frequency of sexual intercourse was not sufficiently reliable and should be interpreted as an estimate only.