The effect of the sex of interviewers on the quality of data in a Nigerian family planning questionnaire.

Traditionally, female interviewers have been preferred to men for conducting fertility and family planning surveys. However, in West Africa, evidence for their superiority over male interviewers is mixed. In Nigeria, as part of a four-state pretest of the national family planning questionnaire, an experimental design was incorporated to quantify effects of the sex of the interviewer. In one state, reinterviews were also performed to measure the reliability of responses. In the conservative northern state of Kano, the use of male interviewers was problematic. However, in the other three states, only weak evidence was found to mitigate against the use of male interviewers. In fact, in two states, the proportion of respondents reporting knowledge of several contraceptive methods was significantly higher when male interviewers conducted the survey. Respondents' reports of contraceptive use were very unreliable for interviewers of both sexes.