Cook Partisan Voting Index Explained

The Cook Partisan Voting Index, abbreviated PVI or CPVI, is a measurement of how partisan[1] a United States congressional district or state is. This partisanship[2] is indicated as lean towards either the Republican Party or the Democratic Party, compared to the nation as a whole, based on how that district or state voted in the previous two presidential elections.[3] [4]

History

The Partisan Voting Index was developed in 1997 by Charlie Cook of The Cook Political Report, in conjunction with Clark Bensen and his political statistical analysis firm, Polidata, "as a means of providing a more accurate picture of the competitiveness".[5] [6] It is based on the methodology introduced by Rob Richie of the Center for Voting and Democracy (FairVote for the Center's July 1997 Monopoly Politics report.[7] [8]

The Cook Political Report has since released new PVI scores every two years. In 2021, the newsletter ended its relationship with Polidata and instead used Dave Leip's Atlas of U.S. Presidential Elections to calculate 2020's results.[9] The most recent iteration is the 2022 Cook Partisan Voting Index, which was released with an updated formula for calculating PVI values.[10]

Calculation and format

The index looks at how every congressional district voted in the past two presidential elections combined and compares it to the national average.[11] The Cook PVI is displayed as a letter, a plus sign, and a number, with the letter (either a D for Democratic or an R for Republican) indicating the party that outperformed in the district and the number showing how many percentage points above the national average it received.[12] In 2022, the formula was updated to weigh the most recent presidential election more heavily than the prior election.

By congressional district

The PVIs for congressional districts are calculated based on the 2016 and 2020 presidential elections. With a PVI of R+1, was determined to be the median congressional district, meaning that exactly 217 districts are more Democratic and 217 are more Republican than this district., in the House, there are 222 districts more Republican than the national average, and 206 districts more Democratic than the national average. The number of swing seats, defined as those between D+5 and R+5, is 87.

By state

The PVIs for states are calculated based on the results of the U.S. presidential elections in 2016 and 2020.[13] The table below reflects the current state of Congress and governors, based on the most recent election results.

StatePVIParty of
governor
Party
in Senate
House
balance<
--USE THIS FORMAT ONLY IF A STATE HAS A NON-DEMOCRATIC, NON-REPUBLICAN REPRESENTATIVEThe house balance values are sorted using the format: where:X is the sort value, written out with 3 digitsY is the house balance in the form #R, #D (or #D, #R depending on who has the majority)

The sort value = 999*#R/(#R+#D), rounded to the nearest integer Example: Alabama (6R, 1D), the sort value = 999*6/7 = 856 Example: California (38D, 15R), the sort value = 999*15/53 = 282 Example: Iowa (Even 2–2), the sort value = 999*2/4 = 500-->

Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
* Includes an independent senator who caucuses with the Democrats.|}

See also

External links

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Notes and References

  1. State-level political partisanship strongly correlates with health outcomes for US children . 10.1007/s00431-021-04203-y . 2022 . Paul . Megan . Zhang . Ruya . Liu . Bian . Saadai . Payam . Coakley . Brian A. . European Journal of Pediatrics . 181 . 273–280 . 34272984 .
  2. Web site: Cillizza . Chris . A map that shows we really do live in two different Americas . CNN . 2017-04-10 . 2023-12-15.
  3. Web site: The differences between real grassroots and "Astroturf" matter . CNN . Chris. Cillizza . 2018-03-14 . 2020-11-29 . Which brings me to the Cook Political Report's Partisan Voting Index or PVI. The goal of the PVI is to compare every congressional district to every other congressional district based on how it has performed in each of the last two presidential elections..
  4. Web site: There are 119 Republican House members who should be VERY nervous today . MSNBC . Steve. Benen . Steve Benen . 2017-02-07 . 2020-11-29 . To get a sense of a congressional district's political leanings, there's a helpful metric called the Partisan Voter Index, or PVI, created 20 years ago by the Cook Political Report..
  5. News: Kurtz . Josh . Future House Opportunities Abound (Maybe) . 22 December 2023 . Roll Call . June 8, 2005.
  6. Book: Daum . Courtenay . Duffy . Robert . Straayer . John . State of Change . 2011 . University of Colorado Press . Boulder . 978-1-4571-1154-9 . 22 December 2023.
  7. News: Cook . Charlie . New Study Identifies 75 Seats That Should Be In Play for '98 Election . 18 January 2024 . Roll Call . August 11, 1997.
  8. Web site: Monopoly Politics. 18 January 2024 . Center for Voting and Democracy . July 1997.
  9. Web site: The Cook Partisan Voting Index (Cook PVI) . The Cook Political Report with Amy Walter . Cook Political Report . 22 December 2023.
  10. Web site: Wasserman . David . Introducing the 2022 Cook Partisan Voting Index (Cook PVI) . The Cook Political Report with Amy Walter . July 13, 2022 . 2022-07-13.
  11. News: Seib . Gerald . GOP Moderates and the Agony Of Their Impeachment Choice . 22 December 2023 . The Wall Street Journal . December 9, 1998.
  12. News: Kane . Paul . New report outlines the deep political polarization's slow and steady march . 22 December 2023 . The Washington Post . April 8, 2023.
  13. Web site: 2022 Cook PVI: State Map and List . The Cook Political Report with Amy Walter . July 12, 2022 . 2022-07-19.