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)

The 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 sociodemographic 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, and distributions by, age, gender, marriage and fertility patterns were broadly similar in both sources. For some countries distributions by educational level varied between the two sources even though both reported using the International Standard Classification of Education, which may reflect variations in the timings of surveys. The wording of health questions and their placement in the questionnaire sometimes differed between the surveys. This may account to some extent for differences between them in estimates of the prevalence of poor health. 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 health indicators