Randomized Response: A Survey Technique for Eliminating Evasive Answer Bias

TLDR

In survey research, respondents often avoid answering truthfully, leading to evasive answer bias that is difficult to assess. The paper argues that this bias can be eliminated by granting interviewees privacy through randomizing their responses. It introduces a randomized response technique for estimating a population proportion. Unbiased maximum‑likelihood estimates are obtained, and their mean‑square errors are shown to be comparable to or better than those of conventional estimators under various population assumptions.

Abstract

Abstract For various reasons individuals in a sample survey may prefer not to confide to the interviewer the correct answers to certain questions. In such cases the individuals may elect not to reply at all or to reply with incorrect answers. The resulting evasive answer bias is ordinarily difficult to assess. In this paper it is argued that such bias is potentially removable through allowing the interviewee to maintain privacy through the device of randomizing his response. A randomized response method for estimating a population proportion is presented as an example. Unbiased maximum likelihood estimates are obtained and their mean square errors are compared with the mean square errors of conventional estimates under various assumptions about the underlying population.