Opening the Opaque Blank Box: An Exploration into Blank and Null Votes in the 2018 Walloon Local Elections

In this article, we propose an in-depth exploration of blank and null ballots in therecent 2018 local elections in Wallonia (Belgium). In the official results, both blankand null ballots are merged together and are classified as invalid votes. Afterobtaining the authorization to access genuine electoral ballots, we study the voteswhich were not considered for the composition of local councils in detail. The data‐set is a representative sample of 13,243 invalidated ballots from 49 Walloonmunicipalities. We first describe how many of these invalidated ballots are blankand how many are null votes, as well as the nature of the nulled votes (unintendederrors or intentionally spoiled ballots). Second, we dig deeper into the differencesbetween ballots that have been intentionally invalidated by voters (blank votes andintentional null votes) and ballots non-intentionally invalidated. Our results showthat most of the ballots (two-thirds) are null ballots and that among them, half are unintentional null ballots. Finally, we show that contextual (socio-demographicand political) factors explain the variations in intentional and unintentional nullvotes across municipalities