In August of 1997, the Cook Political Report introduced the Cook Partisan Voting Index (Cook PVI) to provide a more accurate picture of the competitiveness of each of the 435 congressional districts. With the 2022 PVI release, we made a slight change to how we calculate PVI scores: instead of using a 50/50 mix of the two most recent presidential elections to assess partisanship as we had done in the past, we switched to a 75/25 weighting in favor of the more recent presidential cycle. Using the updated formula, we are now re-releasing PVI scores for every Congress since the 105th (1997-1998).

Explore other years:

1997 (105th Congress)1999 (106th Congress)2001 (107th Congress)2003 (108th Congress)2005 (109th Congress)2007 (110th Congress)2009 (111th Congress)2011 (112th Congress)2012 (Post-Redistricting)2013 (113th Congress)2015 (114th Congress)2017 (115th Congress)2019 (116th Congress)2021 (117th Congress)2023 (118th Congress)

Active CPR subscribers can request the Cook PVI data in spreadsheet format.


Map shapefile: Jeffrey B. Lewis, Brandon DeVine, Lincoln Pitcher, and Kenneth C. Martis. (2013) Digital Boundary Definitions of United States Congressional Districts, 1789-2012. Retrieved from on March 25, 2023.


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