Data sources on the older population in Europe: Comparison of the Generations and Gender Survey (GGS) and the Survey of Health, Ageing and Retirement in Europe (SHARE)

he Survey of Health, Ageing and Retirement in Europe (SHARE) and the Generations and Gender Survey (GGS) are two widely used European longitudinal surveys with data on socio-demographic and health topics, but their comparability has not been systematically investigated. We compared SHARE and GGS data for 50-80 year olds in seven European countries (Belgium, Estonia, France, Germany, Hungary, the Netherlands and Poland) to assess data quality and the potential for joint analyses. The results showed that information on age, gender, marriage and fertility patterns and the corresponding distributions were broadly similar in both sources. For some countries, distributions by educational level varied between the two sources even though both reported using the same International Standard Classification of Education, which may reflect variations in the timings of surveys. The differences also observed for estimates of the prevalence of poor health might come from the wording of health questions and their placement in the questionnaire that sometimes differed between the surveys. We investigated what effect these variations might have on analyses of health inequalities by undertaking multivariable analysis of associations between education and marital status and two standard health indicators: self-reported health (SHR) and long-standing illness (LSI).