Replication data for: Ideological Mapping of American Legislatures

The development and elaboration of the spatial theory of voting has contributed greatly to the study of legislative decision making and elections. Statistical models that estimate the spatial locations of individual legislators have been a key contributor to this success (Poole and Rosenthal 1997, Clinton et al 2004). In addition to applications to the U.S. Congress, spatial models have been estimated for the Supreme Court, U.S. presidents, a large number of non-U.S. legislatures, and supranational organizations. But, unfortunately, a potentially fruitful laboratory for testing spatial theories of policymaking and elections, the American states, has remained relatively unexploited. Two problems have limited the empirical application of spatial theory to the states. The first is that state legislative roll call data has not yet been systematically collected for all states over time. Second, because ideal point models are based on latent scales, comparisons of ideal points across states or even chambers within a state are difficult. This paper reports substantial progress on both fronts. First, we have obtained the roll call voting data for all state legislatures from the mid-1990s onward. Second, we exploit a recurring survey of state legislative candidates to enable comparisons across time, chambers, and states as well as with the U.S. Congress. The resulting mapping of America's state legislatures has tremendous potential to address numerous questions not only about state politics and policymaking, but legislative politics in general.

空间投票理论（spatial theory of voting）的发展与完善，极大地推动了立法决策与选举研究领域的进步。用于估算单个议员空间位置的统计模型，是该领域取得关键突破的核心支撑（Poole与Rosenthal，1997；Clinton等，2004）。除应用于美国国会外，空间模型还被用于美国最高法院、美国总统、大量非美国立法机构以及超国家组织（supranational organizations）的相关研究。但遗憾的是，作为检验政策制定与选举空间理论的极具潜力的研究场景，美国各州的相关研究却长期未得到充分开发。两大问题制约了空间理论在州级层面的实证应用：其一，尚未针对全美各州长期系统性地收集州立法机构的唱名表决数据（roll call data）；其二，由于理想点模型（ideal point models）基于潜变量维度，跨州乃至一州内不同院的理想点比较均存在较大难度。本文在这两方面均取得了实质性进展：其一，我们已获取1990年代中期以来全美所有州立法机构的唱名表决数据；其二，我们借助一项针对州立法候选人的周期性调查，实现了跨时间、跨院、跨州乃至与美国国会的理想点比较。由此构建的美国州立法机构图谱，不仅可为州级政治与政策制定相关的诸多问题提供解答，更能为一般立法政治研究提供重要支撑。