The Cook Partisan Voting Index, abbreviated Cook PVI, CPVI, or PVI, is a measurement of how strongly a United States congressional district or U.S. state leans toward the

Democratic Democrat, Democrats, or Democratic may refer to: Politics *A proponent of democracy, or democratic government; a form of government involving rule by the people. *A member of a Democratic Party: **Democratic Party (United States) (D) **Democratic ...

Republican Party Republican Party is a name used by many political parties around the world, though the term most commonly refers to the United States' Republican Party. Republican Party may also refer to: Africa *Republican Party (Liberia) * Republican Part ...

, compared to the nation as a whole, based on how that district or state voted in the previous two presidential elections. The index is updated after each presidential election cycle, as well as after congressional

redistricting Redistribution (re-districting in the United States and in the Philippines) is the process by which electoral districts are added, removed, or otherwise changed. Redistribution is a form of boundary delimitation that changes electoral dist ...

. '' The Cook Political Report'' first introduced the PVI in August 1997 to better gauge the competitiveness of each district using the

1992 File:1992 Events Collage V1.png, From left, clockwise: 1992 Los Angeles riots, Riots break out across Los Angeles, California after the Police brutality, police beating of Rodney King; El Al Flight 1862 crashes into a residential apartment buildi ...

and

1996 File:1996 Events Collage.png, From left, clockwise: A Centennial Olympic Park bombing, bomb explodes at Centennial Olympic Park in Atlanta, set off by a radical Anti-abortion violence, anti-abortionist; The center fuel tank explodes on TWA Flight 8 ...

presidential elections as a baseline. The most recent iteration is the 2022 Cook Partisan Voting Index, which was released with an updated formula for calculating PVI values.

Calculation and format

The Cook PVI is displayed as a letter, a plus sign, and a number. The letter (either a D for

or an R for Republican) reflects the major party toward which the district (or state) leans. The number reflects the strength of that partisan preference in rounded percentage points. A district or state that "performed within half a point of the national average in either direction" is designated as "Even". PVIs are calculated by comparing the lead candidate's average share of the two-party presidential vote in the past two presidential elections to the party's national average two-party share for those elections. In 2022, it 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 File:2016 Events Collage.png, From top left, clockwise: Bombed-out buildings in Ankara following the 2016 Turkish coup d'état attempt; the impeachment trial of Brazilian President Dilma Rousseff; Damaged houses during the 2016 Nagorno-Karabakh ...

and

2020 2020 was heavily defined by the COVID-19 pandemic, which led to global Social impact of the COVID-19 pandemic, social and Economic impact of the COVID-19 pandemic, economic disruption, mass cancellations and postponements of events, COVID- ...

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 82.

By state

The PVIs for states are calculated based on the results of the U.S. presidential elections in

and

. The table below reflects the current state of Congress and governors, based on the most recent election results.

Extremes and trends

The most

district in the nation is , based in

Oakland Oakland is the largest city and the county seat of Alameda County, California, United States. A major West Coast port, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third largest city overall in the Bay A ...

, with a PVI value of D+40. The most Republican district in the nation is (R+33), represented by Republican Robert Aderholt. With a Cook PVI value of R+25, Wyoming is the most Republican state in the nation. At D+16, Vermont is the most Democratic state, though Washington, D.C., is substantially more partisan with a PVI value of D+43. In the

Senate A senate is a deliberative assembly, often the upper house or chamber of a bicameral legislature. The name comes from the ancient Roman Senate (Latin: ''Senatus''), so-called as an assembly of the senior (Latin: ''senex'' meaning "the el ...

, the most Republican-leaning state to have a Democratic senator is West Virginia (R+22 PVI), represented by Joe Manchin. The least Democratic-leaning state to have two Democratic senators is Georgia (R+3 PVI), represented by Jon Ossoff and Raphael Warnock. The most Democratic-leaning state to have a Republican senator is Maine (D+2 PVI), represented by Susan Collins. The least Republican-leaning states to have two Republican senators are Florida (R+3 PVI), represented by

Marco Rubio Marco Antonio Rubio (born May 28, 1971) is an American politician and lawyer serving as the senior United States senator from Florida, a seat he has held since 2011. A member of the Republican Party, he served as Speaker of the Florida Hous ...

and

Rick Scott Richard Lynn Scott ( Myers, born December 1, 1952) is an American politician serving as the junior United States senator from Florida since 2019. A member of the Republican Party, he was the 45th governor of Florida from 2011 to 2019. Scott ...

, and North Carolina (R+3 PVI), represented by Richard Burr and Thom Tillis.

References

External links