Minimizing participant attrition in panel studies through the use of effective retention and tracking strategies: Review and recommendations

Participant attrition poses a significant threat to the internal and external validity of panel studies, in part because participants who successfully complete all follow-up measurements often differ in significant ways from those respondents lost to attrition. The only certain safeguard against potential biases resulting from attrition is to ensure high interview completion rates during follow-up. Unfortunately, information about reducing preventable attrition is not discussed in most research reports and a comprehensive review paper has not yet been published. The purpose of the present paper is to provide a brief overview of how attrition can threaten the validity of panel studies and to discuss eight promising methods of minimizing attrition through the use of effective retention and tracking strategies. Attempts to reduce attrition are not always met with complete success, therefore, a brief discussion of statistical techniques to assess and correct for potential attrition biases is provided. Finally, methods of calculating attrition rates are suggested along with recommendations for future research.