Abstract As survey response rates decline, correlates of survey participation may also be changing. Panel studies provide an opportunity to study a rich set of correlates of panel attrition over time. We look at changes in attrition rates in the American National Election Studies from 1964 to 2004, a repeated panel survey with a two-wave pre-post election design implemented over multiple decades. We examine changes in attrition rates by three groups of variables: sociodemographic and ecological characteristics of the respondent and household, party affiliation and political and social attitudes recorded at the first interview, and paradata about the first wave interview. We find relatively little overall change in the pre-post election panel attrition rates, but important changes in demographic correlates of panel attrition over time. We also examine contact and cooperation rates from 1988 to 2004.