Factors affecting the participation rates in epidemiologic surveys

Objective The aim of this study was to investigate the response in health-related epidemiological investigation among Chinese population aged 15 and over. We analyzed the specific causes of non-response, and explored the effective ways to improve the response rate, so as to provide reference for future epidemiological studies of this kind. Methods Two modes of studies regarding the prevalence of important cardiovascular diseases were used in Chongqing, during the 12th Five-Year Plan period in oder to find out the cause related to non-response. Intervention programs were carried out to evaluate the effects. Results When using the concentrated mode (CM), the completion rate to the questionnaires was only 20.00% in the pre-investigation, with the response rate as 13.48%. In the deconcentrated mode (DM), the completion rate was 31.16%, with the response rate as 25.19%. After a series of incentives provided to both the respondents and the project-related core staff in the two modes, response rates of the two modes increased to the expected 60%. Conclusions CM appeared having advantages on quality control, but was more time consuming, with higher cost, and without effective follow-up measures to improve the response rate. However, DM had the advantages on controlling the cost and could increase the response rate through making advanced appointment with the households but quality control remained difficult. Two key points should be strengthened to improve the response rates, which including: Precisely finding out the research objects and providing incentives to the respondents to attract their interests of participating in the investigation. Key words: Epidemiological investigation; Non-response; Concentrated mode; Separated mode