Replication Data for: Petitpas A and Sciarini P (2025). The Dynamics of Public Opinion in Direct Democracy Campaigns. British Journal of Political Science.

Do initiative and referendum campaigns enable voters to make coherent decisions? Do the dynamics of opinion formation differ across ballot measures? Despite extensive research on direct democratic processes, these questions remain underexplored. Using rolling cross-section data on two citizen-sponsored initiatives in California and two referendums in Switzerland, we examine the dynamics of voters' knowledge about party cues and arguments for and against ballot measures in the run-up to direct democratic votes. Moreover, we assess the extent to which these dynamics help voters to cast votes that are in line with their party cue and consistent with their position on arguments. The results present a nuanced picture: while campaigns increase voters' knowledge and help them to make more coherent choices, there is significant variation across ballots in knowledge acquisition and resulting degree of in-line and consistent voting.