Replication Data for: The Dynamics of State Policy Liberalism, 1936--2014

Applying a dynamic latent-variable model to data on 148 policies collected over eight decades (1936–2012), we produce the first yearly measure of the policy liberalism of U.S. states. Our dynamic measure of state policy liberalism marks an important advance over existing measures, almost all of which are purely cross-sectional and thus cannot be used to study policy change. We find that, in the aggregate, the policy liberalism of U.S. states steadily increased between the 1930s and 1970s and then largely plateaued. The policy liberalism of most states has remained stable in relative terms, though several states have shifted considerably over time. We also find surprisingly little evidence of multidimensionality in state policy outputs. Our new estimates of state policy liberalism have broad application to the study of political development, representation, accountability, and other important issues in political science.本研究将动态潜变量模型（dynamic latent-variable model）应用于1936年至2012年这八十年间收集的148项政策数据集，首次构建了美国各州政策自由主义程度的年度测度指标。相较于现有绝大多数仅为截面（cross-sectional）性质、无法用于研究政策变迁的测度方法，本研究提出的动态州政策自由主义测度指标实现了重要突破。研究结果显示，整体而言，美国各州的政策自由主义程度在20世纪30年代至70年代间稳步提升，随后基本趋于平稳。多数州的政策自由主义程度在相对维度上保持稳定，但仍有部分州随时间推移发生了显著变化。此外，本研究意外发现，美国州级政策产出几乎不存在多维度特征。本研究构建的州政策自由主义程度新估计值，可广泛应用于政治发展、政治代表、政治问责以及政治学领域其他重要议题的研究。