Evans Brian R, Peterson Bercedis L, Demark-Wahnefried Wendy
Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina 27710, USA.
Cancer Epidemiol Biomarkers Prev. 2004 Feb;13(2):277-8. doi: 10.1158/1055-9965.epi-03-0065.
Mailed surveys are widely used to collect epidemiological and health service data on cancer populations. Nonresponse can threaten the validity of surveys and various strategies, including the enclosure of modest incentives, are often used to increase response rates. A study was undertaken to determine whether response rate to a mailed survey differed with provision of immediate versus delayed incentives. A six-page mailed survey to ascertain dietary supplement use was sent to 1402 men who had been diagnosed with prostate cancer. Subjects were block randomized into two groups based on age (< or =65 years versus >65 years), race (white versus nonwhite), and disease status (locoregional versus distant). One group received a 30-min prepaid phone card concurrently with their blank survey (unconditional incentive), whereas the other group received the incentive only on receipt of their completed survey (conditional incentive). A 60% overall response rate was achieved, and no differences in response rates were noted between conditional and unconditional incentive groups (overall, as well as within defined age, race, and disease-defined strata). Nonwhites, however, were significantly less likely to respond than whites (P < 0.0001). In conclusion, acceptable response rates to a mailed survey can be achieved in a general population of cancer survivors using modest incentives. Given no differences in response rates using conditional versus unconditional incentives, the decision to provide immediate versus delayed incentives is one that should be considered on a study-specific basis, and a decision based primarily on cost. Other means, however, appear necessary to achieve acceptable response rates among minority group cancer survivors.
邮寄调查问卷被广泛用于收集癌症人群的流行病学和卫生服务数据。无应答可能会威胁到调查的有效性，人们常常采用包括附上适度激励措施在内的各种策略来提高应答率。开展了一项研究，以确定邮寄调查问卷的应答率在提供即时激励与延迟激励的情况下是否存在差异。向1402名被诊断患有前列腺癌的男性发送了一份六页的邮寄调查问卷，以确定膳食补充剂的使用情况。根据年龄（≤65岁与＞65岁）、种族（白人与非白人）和疾病状态（局部区域与远处转移）将受试者随机分为两组。一组在收到空白调查问卷的同时收到一张30分钟的预付费电话卡（无条件激励），而另一组仅在收到完整调查问卷时才获得激励（有条件激励）。总体应答率达到60%，有条件激励组和无条件激励组之间在应答率上没有差异（总体以及在特定年龄、种族和疾病定义的分层内）。然而，非白人的应答可能性明显低于白人（P＜0.0001）。总之，在癌症幸存者的普通人群中，使用适度激励措施可以实现邮寄调查问卷可接受的应答率。鉴于使用有条件激励与无条件激励在应答率上没有差异，关于提供即时激励还是延迟激励的决定应根据具体研究情况并主要基于成本来考虑。然而，对于少数族裔癌症幸存者而言，似乎需要采取其他方法来实现可接受的应答率。
