Interviewer effects on underreporting of traditional contraceptive use: evidence from National Family Health Survey-5.

BACKGROUND: Socioeconomic alignment between interviewers and respondents may play a critical role in shaping the accuracy of reported reproductive histories. This study investigates how interviewer characteristics contribute to the reporting of adoption of traditional contraceptive methods using reproductive event calendar data from the fifth round of the National Family Health Survey (2019-21) in India. DATA AND METHODS: Using contraceptive calendar data, a cross-classified multilevel model was employed to assess the interviewer's influence on the reporting of traditional contraceptive method use. The analysis included women aged 15-49 years who reported contraceptive use in the calendar month(s), and the interviewers interviewed them. RESULTS: Multilevel cross-classified models show that interviewer characteristics significantly influence reporting of traditional contraceptive use following periods of non-use, childbirth, or pregnancy termination. Women interviewed by older interviewers (≥30 years; adjusted odds ratio (AOR) = 1.40, p < 0.01) and those who shared the same religion (AOR = 1.21, p ≤ 0.01) and marital status (AOR = 1.42, p < 0.01) as the interviewer were more likely to report traditional contraceptive method use. While women of the same age group (AOR = 0.89, p < 0.05), same-state residence (AOR = 0.82, p < 0.01), and same caste (AOR = 0.94, p < 0.01) as the interviewer were less likely to report traditional contraceptive method use. Older interviewers (AOR = 0.86, p < 0.01), those with secondary education (AOR = 0.54, p < 0.01), those belonging to the Muslim religion (AOR = 0.43, p < 0.01), and those with a lack of prior experience in conducting surveys (AOR = 0.90, p < 0.10) were associated with lower reporting. Moderate (AOR = 1.35, p < 0.01) and high (AOR = 1.22, p < 0.05) levels of prior experience with the same survey schedule in conducting the survey significantly improved reporting. Distribution of variance across different levels indicates substantial variation at the interviewer level (28.50%), followed by the district (18.50%) and PSU (13.46%) levels, suggesting that interviewer effects play a significant role in shaping the outcome. DISCUSSION AND CONCLUSION: Interviewer characteristics such as education, age, and prior survey experience influence the reporting of traditional contraceptive use. Similarities or differences between interviewers and respondents in characteristics such as age, marital status, religion, caste, and state of residence also affect the accuracy and completeness of reporting traditional contraceptive use in contraceptive calendar data.