Dropouts in Longitudinal Surveys

Different types of nonresponse threaten the validity of longitudinal studies: first, initial nonresponse during the recruitment in the baseline survey and second, successive dropout at each time point. Dropout in longitudinal surveys has three separate sources: failure to locate research participants, failure to contact participants, and failure to achieve cooperation. In this entry, specific attention is given to existing knowledge on the correlates of dropout and strategies to limit the problem. To limit nonresponse, a total design approach is advocated with specific attention to each source. That is to limit both noncontact (i.e., failure to locate and subsequent failure to contact a located research participant) and noncooperation.