Social Desirability Bias in Program Evaluation: The Case of a Childhood Nutrition Program in Sri Lanka

We estimate the prevalence of social desirability bias in childhood feeding reports in a UNICEF nutrition cash-plus program in Sri Lanka. Social desirability bias occurs when respondents give the socially “correct” answer, rather than the true answer. While cash benefits were not explicitly conditioned on meeting childhood feeding targets, the training, or “plus” component, made the ideal dietary outcome explicit. We test whether participants misreport the consumption of vitamin A rich foods among young children in this context using list experiments. We find households overstate adherence to program advice by 23 percentage points. The mismeasurement of one feeding component passes through and affects aggregate measures of dietary diversity. The magnitude of the findings suggests that social desirability bias could serve as a potential explanation for the persistent gap between recalled dietary intake and anthropometric outcomes in cash-plus program evaluations. The findings of this study bring together the broader measurement error and program evaluation areas of literature.