Skalland Benjamin, Zhao Zhen, Jeyarajah Jenny
NORC at the University of Chicago.
Centers for Disease Control and Prevention.
Proc Am Stat Assoc. 2014 May 15;20(May 15-18 2014).
In random digit dial (RDD) telephone surveys, advance letters mailed prior to dialing sampled telephone numbers may increase survey response rates (de Leeuw et al. 2007). The ability to mail advance letters to RDD samples relies on the availability of addresses that matched to the sampled telephone numbers. Traditionally, address matching was possible only for landline telephone samples with directory listings, which are not generally available for cell telephone numbers. It is now possible to obtain mailing addresses for a sizeable proportion of cell telephone numbers. Since cell telephone samples are now an increasingly large part of RDD telephone surveys, the use of advance letters mailed prior to dialing cell telephone numbers may result in an increase in response rates similar to those seen for landline telephone numbers. To test this possibility, mailing addresses were obtained for samples of landline and cell telephone numbers in the 2013 National Immunization Survey, a large, national, dual-frame RDD survey sponsored by the Centers for Disease Control and Prevention and fielded by NORC at the University of Chicago. Prior to dialing, advance letters were mailed to half of the cases in the landline and cell telephone samples with available addresses. In this study, we compared address match rates and address accuracy rates between the landline and cell telephone samples and measured the effect of the advance letter on survey response rates in the landline and cell telephone samples. We found that while advance letters had a positive effect on screener completion in the landline sample, they did not impact screener completion in the cell telephone sample. The lack of effect in the cell telephone sample may be due to a higher rate of inaccurate address matching than in the landline telephone sample: in the cell telephone sample, recently-updated addresses were found to be more accurate, and when the analysis was restricted to advance letters mailed to recently-updated addresses, the impact on screener completion in the cell telephone sample was similar to that in the landline sample. We also found that advance letters had a larger positive effect on interview completion in the landline sample, but sample sizes in the cell telephone sample for the experiment were too small to evaluate the impact on interview completion. Implications of these results for dual-frame RDD telephone surveys will be discussed.
在随机数字拨号（RDD）电话调查中，在拨打抽样电话号码之前邮寄预通知信可能会提高调查回应率（de Leeuw等人，2007年）。向RDD样本邮寄预通知信的能力取决于与抽样电话号码匹配的地址的可用性。传统上，地址匹配仅适用于有电话号码簿列表的固定电话样本，而手机号码通常没有此类列表。现在可以为相当一部分手机号码获取邮寄地址。由于手机号码样本现在在RDD电话调查中所占比例越来越大，在拨打手机号码之前邮寄预通知信可能会使回应率提高，类似于固定电话号码的情况。为了检验这种可能性，在2013年全国免疫调查中获取了固定电话和手机号码样本的邮寄地址，该调查是由疾病控制和预防中心发起、芝加哥大学NORC进行实地调查的一项大型全国性双框架RDD调查。在拨打之前，向有可用地址的固定电话和手机号码样本中的一半案例邮寄了预通知信。在本研究中，我们比较了固定电话样本和手机号码样本之间的地址匹配率和地址准确率，并测量了预通知信对固定电话样本和手机号码样本调查回应率的影响。我们发现，虽然预通知信对固定电话样本中的筛选器完成率有积极影响，但对手机号码样本中的筛选器完成率没有影响。手机号码样本中没有效果可能是因为地址匹配不准确的比例高于固定电话样本：在手机号码样本中，发现最近更新的地址更准确，当分析仅限于邮寄给最近更新地址的预通知信时，对手机号码样本中筛选器完成率的影响与固定电话样本中的影响相似。我们还发现，预通知信对固定电话样本中的访谈完成率有更大的积极影响，但实验中手机号码样本的规模太小，无法评估对访谈完成率的影响。将讨论这些结果对双框架RDD电话调查的影响。
