A Meta‐Analysis of Campaign Contributions' Impact on Roll Call Voting*

Objectives. Conventional wisdom about the link between campaign contributions and roll call votes is that contributions rarely matter because groups tend to give to like‐minded legislators. This meta‐analysis examines the conventional wisdom by analyzing published research on this topic. Methods. More than 30 studies are pooled to produce more than 350 individual tests of the contributions‐roll call link. Extending meta‐regression ( Stanley and Jarrell, 1989 ), a logit meta‐analysis is conducted to summarize the literature and assess the importance of various modeling choices. Results. We find that some, but not all, model specifications have an impact on whether significant results are present. Models that control for friendly giving by including a measure of legislators' ideology and that include more than one contributions variable are less likely to produce significant results. Conclusions. After considering the impact of model choice on study results, we conclude that one‐third of roll call votes exhibit the impact of campaign contributions.