Congressional Bipartisanship Scores by Member and Issue Area, 1983–2024

Monday, June 15, 2026

Although bipartisanship has often been considered a cornerstone of effective lawmaking, researchers have struggled to measure it consistently across time and issue areas, making it difficult to build off of each other’s work and have constructive conversations about the topic. In this Center for Effective Lawmaking (CEL) working paper, Mackenzie Dobson, Assistant Professor at the University of Tennessee (and CEL Graduate Affiliate), and Jacob Lollis, Assistant Professor at the University of Cincinnati, take a step toward solving that problem by releasing a comprehensive dataset called Congressional Bipartisanship Scores (CBS), which track how House and Senate members have worked across the aisle from 1983 to the last (118th) Congress. The dataset provides two measurements: a legislator’s bills that draw support from across the aisle, and their cosponsorships supporting someone else’s bills across the aisle. The dataset also breaks scores down by policy area, so researchers can ask about “when, where, and among whom bipartisanship occurs.” The data is freely available through Harvard Dataverse and an R package.

This project was supported and funded by the Portman Center for Policy Solutions at the University of Cincinnati, where both authors serve as research affiliates.

To learn more, read the full report here.

“A Close-Up Shot of People Shaking Hands” by Gustavo Fring is licensed under CC BY-ND 2.0.