*National Cancer Institute, Bethesda, MD †American Cancer Society Inc., Atlanta, GA ‡Westat, Rockville, MD.
Med Care. 2013 Oct;51(10):945-8. doi: 10.1097/MLR.0b013e3182a5023d.
Although response rates for physician surveys have been decreasing, it is not clear whether this trend is associated with an increase in survey nonresponse bias. One means for assessing potential bias is to conduct a level-of-effort analysis that compares data estimates for respondents interviewed during the first recruitment contact to respondents interviewed at later recontact cycles.
We compared early and later responders within the Survey of Physician Attitudes Regarding the Care of Cancer Survivors with respect to both demographic characteristics and aggregate survey responses to items on survivor care knowledge, attitudes, and practices.
Accumulating additional completions across each of 4 respondent contact attempts improved weighted response rates (35.0%, 46.9%, 52.3%, and 57.6%, respectively). However, the majority of estimates for analyzed variables remained relatively unchanged over additional cycles of recontact.
We conclude that additional respondent recontact attempts, especially beyond a single recontact, had little influence on key data distributions, suggesting that these were ineffective in reducing nonresponse bias. Further, the conduct of additional recruitment recontacts was an inefficient means for increasing statistical power. For the conduct of physician surveys, a practice that may in some cases be cost-effective, while also controlling total survey error, is to establish a larger initial sample; to either eliminate nonresponse follow-up or to limit this to one recontact; and to accept a somewhat lower final overall survey response rate.
尽管医生调查的回复率一直在下降,但尚不清楚这种趋势是否与调查无回应偏差的增加有关。评估潜在偏差的一种方法是进行努力程度分析,该分析比较了在第一次招募联系期间接受采访的受访者和在以后的再联系周期中接受采访的受访者的数据估计值。
我们比较了癌症幸存者护理态度调查中早期和晚期的应答者,比较了受访者的人口统计学特征以及对幸存者护理知识、态度和实践项目的综合调查回应。
在每次受访者联系尝试中增加额外的完成量,提高了加权回复率(分别为 35.0%、46.9%、52.3%和 57.6%)。然而,在额外的再联系周期中,大多数分析变量的估计值基本保持不变。
我们得出结论,额外的受访者再联系尝试,尤其是超过一次的再联系尝试,对关键数据分布几乎没有影响,这表明这些尝试在减少无回应偏差方面效果不佳。此外,进行额外的招募再联系是提高统计能力的一种低效手段。对于医生调查的进行,一种在某些情况下可能具有成本效益的做法,同时也控制总调查误差,是建立一个更大的初始样本;要么消除无回应后续行动,要么将其限制在一次再联系;并接受稍低的最终总体调查回复率。