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:
Zoom on Pennsylvania redistricting
Active CPR subscribers can request the Cook PVI data in spreadsheet format.
Map shapefile: United States Census TIGER/Line® Shapefiles
Presidential election data: Before 2020,
Our subscribers have first access to individual race pages for each House, Senate and Governors race, which will include race ratings (each race is rated on a seven-point scale) and a narrative analysis pertaining to that race.