Comparing registration systems using the International Difficulty of Registration Index (IDORI). How difficult is electoral registration in the UK?

Abstract Electoral registration in the UK is often critiqued for making it hard for voters to participate in elections. However, without a tool for a systematic, international comparison, we cannot know if the UK’s system is unusually difficult. To tackle this issue, we make a methodological contribution to the comparative international study of electoral registration. Using four criteria of difficulty, we create an index of difficulty of registration by adapting an American scheme [Jansa, J. M., Motta, M. and Herrick, R. (2021) ‘Finding DORI: Using Item Response Theory to Measure Difficulty of Registration in the U.S. and its Impact on Voters’, American Politics Research, 50: 336–52. https://doi.org/10.1177/1532673X211055050] and use it to code sixty-two countries. Subsequently, we find that the UK has a difficult registration process in comparison to other democracies. We also show that even without implementing automatic registration, there are ways to improve the ease of registration.