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.

倡议公投与全民提案运动能否助力选民做出连贯决策？不同投票提案的舆论形成动态是否存在差异？尽管学界对直接民主程序已开展大量研究，但此类问题仍未得到充分探索。我们采用加州两项公民发起的倡议公投、以及瑞士两项全民公投的滚动截面数据，考察了直接民主投票前夕，选民对政党线索及支持、反对相关提案的论点的认知动态。此外，我们还评估了这些动态在多大程度上能够帮助选民投出符合自身政党立场、且与自身对相关论点所持态度相一致的选票。研究结果呈现出细致入微的图景：尽管竞选活动能够提升选民的认知水平，并助力其做出更具连贯性的选择，但不同投票提案在选民知识获取、以及最终投出符合立场与一致选票的程度上，均存在显著差异。