Estimating the Reduction in Nonresponse Bias From Using a Mail Survey as a Backup for Nonrespondents to a Telephone Interview Survey

Abstract

Because low-income population groups are more likely than higher income groups to live in nontelephone households, the use of telephone interviews to survey low-income groups may result in relatively low contact rates. Other sample members may refuse an interview. Such nonresponse typically has an unknown effect on sample estimates. This article attempts to gauge the relative effects on sample estimates from using a mail survey as a supplemental data collection strategy for increasing the response rate of sample members from a low-income population group who either could not be reached by telephone or who refused to participate in a telephone interview. The assessment is conducted by using variables from the sampling frame and an unbiased comparison sample. Although the use of the mail survey increased response rates by 56%, this resulting increase had only a marginal effect on sample estimates. Implications of these findings for social work researchers and practitioners are discussed in the larger context of estimating and adjusting for nonresponse bias in survey research, and recommendations are suggested for further research.