Perneger T V, Etter J F, Rougemont A
Institute of Social and Preventive Medicine, University of Geneva, Switzerland.
Am J Epidemiol. 1993 Nov 1;138(9):714-22. doi: 10.1093/oxfordjournals.aje.a116909.
Insufficient response rates are a frequent problem in mailed epidemiologic health surveys. As part of a health survey of 1,235 young adults conducted from November 1992 through January 1993 in Geneva, Switzerland, a randomized factorial trial was carried out to assess the contributions of two tactics to increase response rates. The first incentive was the promise of sending 10 Swiss francs (7 US dollars) to respondents; the second was a red postcard, mailed 2 days after the questionnaire, which reminded potential participants to complete the questionnaire. The most effective strategy according to interim analysis was to be selected for follow-up mailings. Two weeks after the first mailing, response rates were 65% for those who had received both incentives, 57% for those who had been offered the money reward only, 54% for recipients of the reminder card, and 48% for those who had received neither incentive (p based on chi 2 (3 df) test < 0.001). The relative hazards of responding were 1.34 (95% confidence interval 1.15-1.55) for the money reward and 1.22 (95% confidence interval 1.05-1.41) for the reminder card. Follow-up mailings to all nonrespondents included both incentives. At the end of data collection, 1,007 persons (82%) had returned the questionnaire. The final response rates were 83, 84, 82, and 78% in the four groups, respectively (p = 0.29). Both the promise of a monetary reward and a reminder postcard considerably improved early response rates. The use of both incentives in follow-up mailings brought final response rates above 80%, except for those who had received no initial incentive. Testing various combinations of incentives in the early stages of a mailed health survey may be a generally useful strategy.
在邮寄式流行病学健康调查中，低回应率是一个常见问题。作为1992年11月至1993年1月在瑞士日内瓦对1235名年轻人进行的健康调查的一部分，开展了一项随机析因试验，以评估两种提高回应率策略的作用。第一种激励措施是承诺向受访者寄送10瑞士法郎（7美元）；第二种是在问卷寄出两天后邮寄一张红色明信片，提醒潜在参与者填写问卷。根据中期分析，将选择最有效的策略用于后续邮寄。首次邮寄两周后，同时收到两种激励措施的人的回应率为65%，仅收到金钱奖励的人的回应率为57%，收到提醒卡的人的回应率为54%，未收到任何激励措施的人的回应率为48%（基于卡方检验（3自由度），p<0.001）。金钱奖励的回应相对风险为1.34（95%置信区间1.15 - 1.55），提醒卡的回应相对风险为1.22（95%置信区间1.05 - 1.41）。对所有未回应者的后续邮寄都包含这两种激励措施。在数据收集结束时，1007人（82%）返回了问卷。四组的最终回应率分别为83%、84%、82%和78%（p = 0.29）。金钱奖励的承诺和提醒明信片都显著提高了早期回应率。在后续邮寄中同时使用这两种激励措施使最终回应率超过了80%，但未收到任何初始激励措施的人除外。在邮寄式健康调查的早期阶段测试各种激励措施组合可能是一种普遍有用的策略。
