Response Bias in Survey Measures of Voter Behavior: Implications for Measurement and Inference

This short report exploits a unique opportunity to investigate the implications of response bias in survey questions about voter turnout and vote choice in new democracies. We analyze data from a field experiment in Benin, where we gathered official election results and panel survey data representative at the village level, allowing us to directly compare average outcomes across both measurement instruments in a large number of units. We show that survey respondents consistently overreport turning out to vote and voting for the incumbent, and that the bias is large and worse in contexts where question sensitivity is higher. This has important implications for the inferences we draw about an experimental treatment, indicating that the response bias we identify is correlated with treatment. Although the results using the survey data suggest that the treatment had the hypothesized impact, they are also consistent with social desirability bias. By contrast, the administrative data lead to the conclusion that the treatment had no effect.