“…The issue of non-response in longitudinal surveysboth initial non-response and subsequent attritionhas a distinguished history in survey research and statistics (Sudman and Bradburn 1974;Groves and Couper 1998;Little and Rubin 1987). Most of the existing literature has focused on non-ageing panels in the United States, especially during earlier time periods when attrition rates typically were considerably lower.…”