Differences in participation rates and lessons learned about recruitment of participants - The European Health Examination Survey Pilot Project

Aims: In the 1980s, participation rates in health interview and health examination surveys were around 80% while now they are around 50-60%. There is also evidence that non-participation is selective. Low participation rates and selective non-participation may cause bias to our survey results based on participants alone. We aim to increase knowledge on cultural differences in acceptance and feasibility of different recruitment methods. Methods: The European Health Examination Survey Pilot Project, conducted in 2009-2012, included pilot surveys in 12 countries among people aged 25-64 years. Information about recruitment methods and participation rates in these surveys was collected. Results: Participation rates ranged from 16% to 57% for men and from 31% to 74% for women, where in most surveys women had higher participation rates than men. A variety of recruitment and promotion methods were used to obtain as high participation rates as possible. Combinations of phone calls, invitation letter and home visits were used to recruit invitees. Obtaining valid phone numbers for survey invitees was difficult in several countries. Incentives, websites and promotion in local media were used to promote the surveys. Conclusions: The European Health Examination Survey Pilot surveys showed that obtaining a participation rate above 50% for a representative population sample is possible but it requires hard work and a well-planned recruitment strategy. Recruitment methods used in one country may not be possible to use in another country due to cultural norms and national regulations.