ABSTRACT Objectives The main goal of this article is to investigate individual‐level standards of evidence in the political realm. Our specific objective is to understand what evidentiary standards voters rely on when they evaluate the effectiveness of legislation passed by their in‐party versus an out‐party. Methods Our empirical investigation is based on original survey data collected in August 2023 in the United States. We presented people with a hypothetical economic policy, and we randomized policy authorship (Democrat / Republican / Bipartisan). Respondents were then asked to state what outcomes they would need to observe to evaluate whether the presented policy was effective. Results Our analysis provides two main findings. First, both Democrats and Republicans apply looser evidentiary standards for policies passed by their own party. Second, we find that policy authorship also influences the type of evidence that people rely on when they evaluate policy. Our models suggest that individuals are (1) less likely to consider long time horizons and (2) less likely to reflect on alternative causes when they evaluate the efficacy of a bipartisan economic policy compared to one authored by only one major party. Conclusion Our findings suggest that Democrats and Republicans consider their own policies as more efficacious at least in part because they have adopted less stringent standards for perceived policy success. Thus, our work highlights a novel cognitive process that contributes to partisan bias in policy evaluation.
Justwan et al. (Sat,) studied this question.