Measuring change in sexual behavior: Concordance between survey measures

Measuring change in sexual behavior as reliably as possible is a crucial me thodological issue in evaluation research. We compared two methods of asses sing behavior change: the retrospective change method, which asks responden ts about change explicitly by asking whether they have made any changes in their sexual behavior in a past time period and the longitudinal or panel m ethod, which asks respondents at two different times about their sexual beh avior and compares the two sets of answers. Among heterosexual men and wome n (N = 962) in the AIDS in Multi-Ethnic Neighborhoods (AMEN) Cohort Survey the two methods of measuring change in condom use agreed with a kappa of 0. 38. The same was true among gay men (N = 596) where kappa for agreement was 0.35. However among both heterosexuals and gay men, the two methods of mea suring change in number of partners had a small but significant level of di sagreement. Among heterosexuals, kappa was -0.14; among gay men, kappa was -0.16. Where the two types of change measures disagree, the data do not per mit us to say which measure is more valid. Further research on concordance between measures of change in sexual behavior and on validity of change mea sures is recommended.