Identification of attrition bias using different types of panel refreshments

Selective attrition out of longitudinal datasets is a concern for empirical researchers. This paper discusses a simple way to identify both direction and magnitude of potential sample bias in household panels. The idea is to exploit multiple types of simultaneous entries into the panel. The little known phenomenon of natural refreshments, which adds to entries through refreshments induced by data collectors, allows disentangling attrition bias from measurement errors connected to differences in participation experience (i.e. panel conditioning). A demonstrative application on subjective data from the German Socio-Economic Panel Study (SOEP) serves as an example and offers insights on health-related attrition.