The Impact of 2022 Redistricting
The Hyper-Competitive Swing Seat Decline, 1997-2022
- David Wasserman, Senior Editor, U.S. House of Representatives
A note on the Cook PVI℠ formula change
Beginning with this decade, we're making a slight formula 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've done in the past, we're switching to a 75/25 weighting in favor of the more recent presidential election. For the 2022 dataset, that means that the 2020 result in each state district is weighted three times as heavily as the 2016 result.
Since we first launched the Cook PVI in 1997, there's been a dramatic increase in "straight-ticket" voting, with fewer voters choosing candidates of different parties for the White House and Congress. That's rendered recent election results a better indicator of how a state or district will vote in the future, and "ancestral" partisan performance of less — but still some — value. In short, as electoral realities have changed, the Cook PVI must change with them.
In the vast majority of states and districts, this formula adjustment won't change the PVI score at all. But for places that have seen rapid shifts towards one party or the other in the last six years — such as in South Florida or suburbs of Dallas — the new formula "leans in" to the transformation underway. To ensure consistency, all 2021 (pre-redistricting) and 2022 (post-redistricting) PVI scores cited in this report reflect the new formula.
Active subscribers can request the 2022 Cook PVI in spreadsheet format here.
(Cook PVI℠) is a service mark of Invincible Summer Media, Inc.
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.