Drivers of Congressional Behavior: Analyzing Members, Constituents, and Committees With CongressData

The US Congress is the world’s most studied legislature, but data on its many facets often remains isolated. This note introduces an updated version of CongressData, a database of over 1300 member-year and district-year level variables between 1789 and 2024 that compiles district demographics and economic variables, legislator characteristics, lawmaking behavior, and committee membership. We also introduce an R package that makes it easy to subset and cite data and an associated web app. We first draw attention to the metadata in CongressData. Then, leveraging CongressData, we highlight analyses that cut across these types of data. Our illustration uses dimensional analysis on the the determinants of bill introduction by Members of Congress. In doing so, we assess several prominent explanations for bill in-troduction. Exploring the factors that govern this focus, we find that committee membership is more associated than party, ideology, member characteristics, or district demographics. The dataset will aid scholars of Congress and American institutions, enabling them to adjudicate between different factors to explain the phenomena of interest to them.