Panel Attrition and its Effects on Results from a Longitudinal Study: An Examination of Changes in Participants and Attitudes in a Web-Based Panel Survey of HIV and AIDS Stigma Attitudes
Baxter, R., & Dean, L. (2004, May). Panel Attrition and its Effects on Results from a Longitudinal Study: An Examination of Changes in Participants and Attitudes in a Web-Based Panel Survey of HIV and AIDS Stigma Attitudes. Presented at American Association for Public Opinion Research 59th Annual Conference, Phoenix, AZ.
Longitudinal studies offer the opportunity to examine trendsover time both in terms of participation and attitudes. However, the loss of participants from one wave to another can result in bias ofsurvey results. The Study of HIV and AIDS Stigma, conducted for theCenters for Disease Control (CDC), is a longitudinal study of anational, RDD selected Knowledge Networks panel investigating knowledgeof HIV and AIDS, as well as attitudes and beliefs surrounding thisissue. The survey was initially conducted in summer 2000 with afollow-up in spring 2003. Comparisons are made of panel participantsand non-participants between the 2 waves, as well as changes inattitudes. Non-participants at time 2 include non-respondents who arestill on the panel, and non-respondents from attrition (who have chosento withdraw from the panel). In addition, we investigate changes inattitudes over time and discuss the implications of differing panelparticipation on those changing attitudes and how this may result inbiased data. Analysis indicates that participants with more positiveattitudes in wave 1 were less likely to participate in wave 2 resultingin potential bias to the results.