Vote overreporting in national election surveys: a 55-nation exploratory study

Abstract

Election turnout is central to the health of a democracy, yet measuring it accurately in national election surveys presents major problems. Surveys show that respondents consistently overreport their turnout, usually by between 10 and 20 percentage points. To date, most research has been conducted on the United States, and what little comparative research exists has typically covered a small number of countries. In this paper, we present the largest comparative study yet undertaken on turnout overreporting. By utilizing 20 years of data from the Comparative Study of Electoral Systems (CSES), we analyse 184 elections across 55 different states. We examine the importance of the survey method and the election context as explanations for overreporting. The results suggest that aspects of both may shape the degree of error. These exploratory results provide a corrective to current studies by showing that institutional and contextual factors may be at least as important as survey method in shaping overreporting.