Focus on research methods - An evaluation of a self-generated identification code

We describe a self-generated coding form used in a study of HIV prevention practices of college students and provide information on the success rate o f matching questionnaires over a 3-year period using the form. The data for this study were from a longitudinal study of HIV risk-reduction practices of college students. In order to match questionnaires over the 3-year study period while maintaining anonymity, participants were asked to complete a self-generated identification form at each data collection point, in the se cond year of the project, we were able to successfully match 74.3% of the q uestionnaires to those returned during the first year using 6 to 8 of the c ode elements on the form, and in the third year, we were able to match 73% of questionnaires to those returned in the second year. Participants for wh om questionnaires matched were more likely than participants with unmatched questionnaires to be white students enrolled as underclassmen. (C) 2000 Jo hn Wiley & Sons, Inc.