Below are the data sets used for the creation of the Legislative Effectiveness Scores (LES) and Issue Area Data. For more information about how these are constructed, go to our FAQ and Methodology pages.
All House data from 93rd-118th Congress (1973-2024) (including both LES 1.0 and 2.0).
For House data: Volden, Craig, and Alan E. Wiseman. 2014. Legislative Effectiveness in the United States Congress: The Lawmakers. New York: Cambridge University Press; updated at www.thelawmakers.org.
For Senate data: Volden, Craig, and Alan E. Wiseman. 2018. “Legislative Effectiveness in the United States Senate,” Journal of Politics 80(2): 731-735; updated at www.thelawmakers.org.
For States data: Bucchianeri, Peter, Craig Volden, and Alan E. Wiseman. 2025. “Legislative Effectiveness in the American States,” American Political Science Review 119(1): 21–39; updated at www.thelawmakers.org.