Polling clerks’ errors in face matching

The UK 2024 general election was the first for which voters were required to prove their identity using a photo Identity Document (ID). Opposition to this change focused on the way it might affect participation, rather than the accuracy of photo ID itself. However, research demonstrates that people are generally poor at matching unfamiliar faces, including checking ID. We tested polling clerks who were responsible for ID checks in the 2024 general election. Using standard tests of face matching, polling clerks made multiple errors in simple match/mismatch decisions (Glasgow Face Matching Test: 16% errors; Kent Face Matching Test: 36% errors), levels of performance that are typical across the population. Individual differences were large, with some clerks performing accurately, and others much less so. There was a significant decline in accuracy over age, with older clerks (on average) scoring poorly. The same tests were administered to a volunteer group of university students, who had taken no part in the election. These students made very similar levels of errors. As with the general population and other professional groups, polling clerks are prone to error in face matching. For this reason, photo ID does not provide a reliable proof of identity at the point of voting.