Cook Partisan Voting Index

Map by state (After the 2012 election)

The Cook Partisan Voting Index, also called PVI, is a measurement of how strongly a United States congressional district or state leans toward the Democratic or Republican Party, compared to the nation as a whole. The Cook Political Report introduced the PVI in August 1997 to better gauge the competitiveness of each district using the 1992 and 1996 presidential elections as a baseline.^[1] The index is based on analysis by the Center for Voting and Democracy (now FairVote) for its July 1997 Monopoly Politics report.^[2]

Calculation

PVIs are calculated by comparing the district's average Democratic or Republican Party's share of the two-party presidential vote in the past two presidential elections to the nation's average share of the same. The national average for 2004 and 2008 was 51.2% Democratic to 48.8% Republican.^[1] For example, in Alaska's at-large congressional district, the Republican candidate won 63% and 61% of the two-party share in the 2004 and 2008 presidential elections, respectively. Comparing the average of these two results (62%) against the average national share (49%), this district has voted 13 percentage points more Republican than the country as a whole, or R+13.

Prior to its April 2009 update, the PVI formula was calculated by comparing district-level results for the past two presidential elections to nationwide results for the most recent election. David Nir of the Swing State Project advocated a change to the new formula, and Charlie Cook agreed, wanting an "apples to apples" comparison.^[3]

Format

The Cook PVI is formatted as a letter, plus sign, and number:

• Letter: The major party, Democratic (D) or Republican (R), to which the district leans
• Number: The extent of that lean, in rounded percentage points

For districts without a lean, the index written as "EVEN" without a number.

List of PVIs

Extremes and trends

The most Democratic congressional district in the country is New York's 15th, located in the Bronx, with a PVI of D+43. The most Republican district is Texas's 13th at R+32. As for states as a whole, Wyoming and Utah are the most Republican at R+22, and Hawaii is the most Democratic at D+20.

The most Democratic congressional district to be represented by a Republican is Illinois' 10th, which has a PVI of D+8. The district is represented by Robert Dold. The most Republican congressional districts to be represented by Democrats are Minnesota's 7th and Florida's 2nd, both of which have a PVI of R+6. Minnesota's 7th is represented by Collin Peterson while Florida's 2nd is represented by Gwen Graham. In total there are nine Democratic-leaning House districts represented by Republicans following the 2014 elections (up from five from before the election) and eight Republican-leaning House districts represented by Democrats (down from 15 before the election). This represents a total of 17 out of 435 Representatives from districts with a PVI opposite to their own party.

In the Senate, the most Republican-leaning state to have a Democratic senator is West Virginia, with Democrat Joe Manchin. The least Democratic-leaning state to have two Democratic senators is Virginia, represented by Mark Warner and Tim Kaine, with no Republican-leaning states at all having elected two Democrats as of the 2014 elections. The most Democratic-leaning state to have a Republican senator is Illinois, with Republican Mark Kirk. The most Democratic-leaning state to have two Republican senators is Iowa, represented by Chuck Grassley and Joni Ernst.

Three Republican-leaning states (the most Republican being West Virginia at R+13) have governors from the Democratic Party while ten Democratic-leaning states (the most Democratic being Maryland and Massachusetts at D+10) have governors from the Republican Party.

All Republican-leaning states have a majority Republican house delegation, as well as six Democratic-leaning states and neutral Virginia. The most Democratic-leaning state to have a majority Republican house delegation is Michigan at D+4, while the least Democratic-leaning state to have a majority Democratic delegation is Minnesota at D+2. Massachusetts has the largest number of Representatives (nine) of the six states that have entirely Democratic delegations; Oklahoma has the largest number of Representatives (five) of the eleven states that have entirely Republican delegations. Note that the seven states with only one representative must be among these; two are Democratic (Delaware and Vermont) and five are Republican (Wyoming, South Dakota, North Dakota, Montana, and Alaska).

By congressional district This table is sourced from the Cook Political Report's 2012 analysis for districts of the 113th United States Congress, calculated according to the results of the 2008 and the 2012 U.S. presidential elections.[4] The party representations are based on the winners of the 2014 U.S. House elections. In the House, there are 241 districts that lean Republican, and 185 districts that lean Democratic. There are 9 seats at "EVEN" PVI. The number of swing seats – defined as those with PVI scores between R+5 and D+5 – has fallen to a record low of 90.[1] State District PVI Party of Representative Alabama 1st R+15 Republican Alabama 2nd R+17 Republican Alabama 3rd R+16 Republican Alabama 4th R+28 Republican Alabama 5th R+17 Republican Alabama 6th R+28 Republican Alabama 7th D+20 Democratic Alaska At-large R+12 Republican Arizona 1st R+4 Democratic Arizona 2nd R+3 Republican Arizona 3rd D+8 Democratic Arizona 4th R+20 Republican Arizona 5th R+17 Republican Arizona 6th R+12 Republican Arizona 7th D+16 Democratic Arizona 8th R+15 Republican Arizona 9th R+1 Democratic Arkansas 1st R+14 Republican Arkansas 2nd R+8 Republican Arkansas 3rd R+19 Republican Arkansas 4th R+15 Republican California 1st R+10 Republican California 2nd D+20 Democratic California 3rd D+3 Democratic California 4th R+10 Republican California 5th D+19 Democratic California 6th D+18 Democratic California 7th EVEN Democratic California 8th R+10 Republican California 9th D+6 Democratic California 10th R+1 Republican California 11th D+17 Democratic California 12th D+34 Democratic California 13th D+37 Democratic California 14th D+23 Democratic California 15th D+16 Democratic California 16th D+7 Democratic California 17th D+20 Democratic California 18th D+18 Democratic California 19th D+19 Democratic California 20th D+21 Democratic California 21st D+2 Republican California 22nd R+10 Republican California 23rd R+16 Republican California 24th D+4 Democratic California 25th R+3 Republican California 26th D+4 Democratic California 27th D+11 Democratic California 28th D+20 Democratic California 29th D+25 Democratic California 30th D+14 Democratic California 31st D+5 Democratic California 32nd D+12 Democratic California 33rd D+11 Democratic California 34th D+30 Democratic California 35th D+15 Democratic California 36th R+1 Democratic California 37th D+34 Democratic California 38th D+12 Democratic California 39th R+5 Republican California 40th D+29 Democratic California 41st D+9 Democratic California 42nd R+10 Republican California 43rd D+26 Democratic California 44th D+32 Democratic California 45th R+7 Republican California 46th D+9 Democratic California 47th D+8 Democratic California 48th R+7 Republican California 49th R+4 Republican California 50th R+14 Republican California 51st D+16 Democratic California 52nd D+2 Democratic California 53rd D+10 Democratic Colorado 1st D+18 Democratic Colorado 2nd D+8 Democratic Colorado 3rd R+5 Republican Colorado 4th R+11 Republican Colorado 5th R+13 Republican Colorado 6th D+1 Republican Colorado 7th D+5 Democratic Connecticut 1st D+13 Democratic Connecticut 2nd D+5 Democratic Connecticut 3rd D+11 Democratic Connecticut 4th D+5 Democratic Connecticut 5th D+3 Democratic Delaware At-large D+8 Democratic Florida 1st R+21 Republican Florida 2nd R+6 Democratic Florida 3rd R+14 Republican Florida 4th R+19 Republican Florida 5th D+21 Democratic Florida 6th R+9 Republican Florida 7th R+4 Republican Florida 8th R+9 Republican Florida 9th D+8 Democratic Florida 10th R+6 Republican Florida 11th R+11 Republican Florida 12th R+7 Republican Florida 13th R+1 Republican Florida 14th D+13 Democratic Florida 15th R+6 Republican Florida 16th R+6 Republican Florida 17th R+10 Republican Florida 18th R+3 Democratic Florida 19th R+12 Republican Florida 20th D+29 Democratic Florida 21st D+10 Democratic Florida 22nd D+3 Democratic Florida 23rd D+9 Democratic Florida 24th D+34 Democratic Florida 25th R+5 Republican Florida 26th R+1 Republican Florida 27th R+2 Republican Georgia 1st R+9 Republican Georgia 2nd D+6 Democratic Georgia 3rd R+19 Republican Georgia 4th D+21 Democratic Georgia 5th D+32 Democratic Georgia 6th R+14 Republican Georgia 7th R+14 Republican Georgia 8th R+15 Republican Georgia 9th R+30 Republican Georgia 10th R+14 Republican Georgia 11th R+19 Republican Georgia 12th R+9 Republican Georgia 13th D+16 Democratic Georgia 14th R+26 Republican Hawaii 1st D+18 Democratic Hawaii 2nd D+21 Democratic Idaho 1st R+18 Republican Idaho 2nd R+17 Republican Illinois 1st D+28 Democratic Illinois 2nd D+29 Democratic Illinois 3rd D+5 Democratic Illinois 4th D+29 Democratic Illinois 5th D+16 Democratic Illinois 6th R+4 Republican Illinois 7th D+36 Democratic Illinois 8th D+8 Democratic Illinois 9th D+15 Democratic Illinois 10th D+8 Republican Illinois 11th D+8 Democratic Illinois 12th EVEN Republican Illinois 13th EVEN Republican Illinois 14th R+5 Republican Illinois 15th R+14 Republican Illinois 16th R+4 Republican Illinois 17th D+7 Democratic Illinois 18th R+11 Republican Indiana 1st D+10 Democratic Indiana 2nd R+6 Republican Indiana 3rd R+13 Republican Indiana 4th R+11 Republican Indiana 5th R+9 Republican Indiana 6th R+12 Republican Indiana 7th D+13 Democratic Indiana 8th R+8 Republican Indiana 9th R+9 Republican Iowa 1st D+5 Republican Iowa 2nd D+4 Democratic Iowa 3rd EVEN Republican Iowa 4th R+5 Republican Kansas 1st R+23 Republican Kansas 2nd R+8 Republican Kansas 3rd R+6 Republican Kansas 4th R+14 Republican Kentucky 1st R+18 Republican Kentucky 2nd R+16 Republican Kentucky 3rd D+4 Democratic Kentucky 4th R+16 Republican Kentucky 5th R+25 Republican Kentucky 6th R+9 Republican Louisiana 1st R+26 Republican Louisiana 2nd D+23 Democratic Louisiana 3rd R+19 Republican Louisiana 4th R+13 Republican Louisiana 5th R+15 Republican Louisiana 6th R+21 Republican Maine 1st D+9 Democratic Maine 2nd D+2 Republican Maryland 1st R+14 Republican Maryland 2nd D+10 Democratic Maryland 3rd D+9 Democratic Maryland 4th D+26 Democratic Maryland 5th D+14 Democratic Maryland 6th D+4 Democratic Maryland 7th D+24 Democratic Maryland 8th D+11 Democratic Massachusetts 1st D+13 Democratic Massachusetts 2nd D+8 Democratic Massachusetts 3rd D+6 Democratic Massachusetts 4th D+6 Democratic Massachusetts 5th D+14 Democratic Massachusetts 6th D+4 Democratic Massachusetts 7th D+31 Democratic Massachusetts 8th D+6 Democratic Massachusetts 9th D+5 Democratic Michigan 1st R+5 Republican Michigan 2nd R+7 Republican Michigan 3rd R+4 Republican Michigan 4th R+5 Republican Michigan 5th D+10 Democratic Michigan 6th R+1 Republican Michigan 7th R+3 Republican Michigan 8th R+2 Republican Michigan 9th D+6 Democratic Michigan 10th R+6 Republican Michigan 11th R+4 Republican Michigan 12th D+15 Democratic Michigan 13th D+34 Democratic Michigan 14th D+29 Democratic Minnesota 1st R+1 Democratic Minnesota 2nd R+2 Republican Minnesota 3rd R+2 Republican Minnesota 4th D+11 Democratic Minnesota 5th D+22 Democratic Minnesota 6th R+10 Republican Minnesota 7th R+6 Democratic Minnesota 8th D+1 Democratic Mississippi 1st R+16 Republican Mississippi 2nd D+13 Democratic Mississippi 3rd R+14 Republican Mississippi 4th R+21 Republican Missouri 1st D+28 Democratic Missouri 2nd R+8 Republican Missouri 3rd R+13 Republican Missouri 4th R+13 Republican Missouri 5th D+9 Democratic Missouri 6th R+12 Republican Missouri 7th R+19 Republican Missouri 8th R+17 Republican Montana At-large R+7 Republican Nebraska 1st R+10 Republican Nebraska 2nd R+4 Democratic Nebraska 3rd R+23 Republican Nevada 1st D+14 Democratic Nevada 2nd R+5 Republican Nevada 3rd EVEN Republican Nevada 4th D+4 Republican New Hampshire 1st R+1 Republican New Hampshire 2nd D+3 Democratic New Jersey 1st D+13 Democratic New Jersey 2nd D+1 Republican New Jersey 3rd R+1 Republican New Jersey 4th R+7 Republican New Jersey 5th R+4 Republican New Jersey 6th D+8 Democratic New Jersey 7th R+6 Republican New Jersey 8th D+24 Democratic New Jersey 9th D+14 Democratic New Jersey 10th D+34 Democratic New Jersey 11th R+6 Republican New Jersey 12th D+14 Democratic New Mexico 1st D+7 Democratic New Mexico 2nd R+5 Republican New Mexico 3rd D+8 Democratic New York 1st R+2 Republican New York 2nd R+1 Republican New York 3rd EVEN Democratic New York 4th D+3 Democratic New York 5th D+35 Democratic New York 6th D+13 Democratic New York 7th D+34 Democratic New York 8th D+35 Democratic New York 9th D+32 Democratic New York 10th D+23 Democratic New York 11th R+2 Republican New York 12th D+27 Democratic New York 13th D+42 Democratic New York 14th D+26 Democratic New York 15th D+43 Democratic New York 16th D+21 Democratic New York 17th D+5 Democratic New York 18th EVEN Democratic New York 19th D+1 Republican New York 20th D+7 Democratic New York 21st EVEN Republican New York 22nd R+3 Republican New York 23rd R+3 Republican New York 24th D+5 Republican New York 25th D+7 Democratic New York 26th D+12 Democratic New York 27th R+8 Republican North Carolina 1st D+19 Democratic North Carolina 2nd R+10 Republican North Carolina 3rd R+11 Republican North Carolina 4th D+20 Democratic North Carolina 5th R+11 Republican North Carolina 6th R+10 Republican North Carolina 7th R+12 Republican North Carolina 8th R+11 Republican North Carolina 9th R+8 Republican North Carolina 10th R+11 Republican North Carolina 11th R+13 Republican North Carolina 12th D+26 Democratic North Carolina 13th R+8 Republican North Dakota At-large R+10 Republican Ohio 1st R+6 Republican Ohio 2nd R+8 Republican Ohio 3rd D+17 Democratic Ohio 4th R+9 Republican Ohio 5th R+7 Republican Ohio 6th R+8 Republican Ohio 7th R+6 Republican Ohio 8th R+15 Republican Ohio 9th D+15 Democratic Ohio 10th R+3 Republican Ohio 11th D+30 Democratic Ohio 12th R+8 Republican Ohio 13th D+11 Democratic Ohio 14th R+4 Republican Ohio 15th R+6 Republican Ohio 16th R+6 Republican Oklahoma 1st R+18 Republican Oklahoma 2nd R+20 Republican Oklahoma 3rd R+26 Republican Oklahoma 4th R+19 Republican Oklahoma 5th R+12 Republican Oregon 1st D+7 Democratic Oregon 2nd R+10 Republican Oregon 3rd D+22 Democratic Oregon 4th D+2 Democratic Oregon 5th EVEN Democratic Pennsylvania 1st D+28 Democratic Pennsylvania 2nd D+38 Democratic Pennsylvania 3rd R+8 Republican Pennsylvania 4th R+9 Republican Pennsylvania 5th R+8 Republican Pennsylvania 6th R+2 Republican Pennsylvania 7th R+2 Republican Pennsylvania 8th R+1 Republican Pennsylvania 9th R+14 Republican Pennsylvania 10th R+12 Republican Pennsylvania 11th R+6 Republican Pennsylvania 12th R+9 Republican Pennsylvania 13th D+13 Democratic Pennsylvania 14th D+15 Democratic Pennsylvania 15th R+2 Republican Pennsylvania 16th R+4 Republican Pennsylvania 17th D+4 Democratic Pennsylvania 18th R+10 Republican Rhode Island 1st D+15 Democratic Rhode Island 2nd D+8 Democratic South Carolina 1st R+11 Republican South Carolina 2nd R+16 Republican South Carolina 3rd R+18 Republican South Carolina 4th R+15 Republican South Carolina 5th R+9 Republican South Carolina 6th D+21 Democratic South Carolina 7th R+7 Republican South Dakota At-large R+10 Republican Tennessee 1st R+25 Republican Tennessee 2nd R+20 Republican Tennessee 3rd R+16 Republican Tennessee 4th R+18 Republican Tennessee 5th D+5 Democratic Tennessee 6th R+21 Republican Tennessee 7th R+18 Republican Tennessee 8th R+19 Republican Tennessee 9th D+25 Democratic Texas 1st R+24 Republican Texas 2nd R+16 Republican Texas 3rd R+17 Republican Texas 4th R+25 Republican Texas 5th R+17 Republican Texas 6th R+11 Republican Texas 7th R+13 Republican Texas 8th R+29 Republican Texas 9th D+25 Democratic Texas 10th R+11 Republican Texas 11th R+31 Republican Texas 12th R+19 Republican Texas 13th R+32 Republican Texas 14th R+12 Republican Texas 15th D+5 Democratic Texas 16th D+12 Democratic Texas 17th R+13 Republican Texas 18th D+24 Democratic Texas 19th R+26 Republican Texas 20th D+6 Democratic Texas 21st R+12 Republican Texas 22nd R+15 Republican Texas 23rd R+3 Republican Texas 24th R+13 Republican Texas 25th R+12 Republican Texas 26th R+20 Republican Texas 27th R+13 Republican Texas 28th D+7 Democratic Texas 29th D+12 Democratic Texas 30th D+27 Democratic Texas 31st R+12 Republican Texas 32nd R+10 Republican Texas 33rd D+18 Democratic Texas 34th D+8 Democratic Texas 35th D+11 Democratic Texas 36th R+25 Republican Utah 1st R+27 Republican Utah 2nd R+18 Republican Utah 3rd R+28 Republican Utah 4th R+16 Republican Vermont At-large D+16 Democratic Virginia 1st R+6 Republican Virginia 2nd R+2 Republican Virginia 3rd D+27 Democratic Virginia 4th R+4 Republican Virginia 5th R+5 Republican Virginia 6th R+12 Republican Virginia 7th R+10 Republican Virginia 8th D+16 Democratic Virginia 9th R+15 Republican Virginia 10th R+2 Republican Virginia 11th D+10 Democratic Washington 1st D+4 Democratic Washington 2nd D+8 Democratic Washington 3rd R+2 Republican Washington 4th R+13 Republican Washington 5th R+7 Republican Washington 6th D+5 Democratic Washington 7th D+29 Democratic Washington 8th R+1 Republican Washington 9th D+17 Democratic Washington 10th D+5 Democratic West Virginia 1st R+14 Republican West Virginia 2nd R+11 Republican West Virginia 3rd R+14 Republican Wisconsin 1st R+3 Republican Wisconsin 2nd D+17 Democratic Wisconsin 3rd D+5 Democratic Wisconsin 4th D+23 Democratic Wisconsin 5th R+13 Republican Wisconsin 6th R+5 Republican Wisconsin 7th R+2 Republican Wisconsin 8th R+2 Republican Wyoming At-large R+22 Republican The following district is ranked on the Cook PVI, as it participates in presidential elections. It is represented by a non-voting delegate. Territory District PVI Party of Delegate District of Columbia At-large D+40 Democratic The following districts are not ranked on the Cook PVI, as they are territories that do not participate in presidential elections. Each is represented by a non-voting delegate. Territory District PVI Party of Delegate American Samoa At-large N/A Republican Guam At-large N/A Democratic Northern Mariana Islands At-large N/A Democratic Puerto Rico At-large N/A New Progressive* United States Virgin Islands At-large N/A Democratic *Member of territorial party identifies as a Democrat nationally.

By state The PVIs for states are calculated based on the 2008 and 2012 presidential election; the PVI figures below are from 2014.[5] For vacant offices, party representation is based on the most recent officeholder. State PVI Party of Governor Party in Senate House balance Alabama R+14 Republican Republican 6R, 1D Alaska R+12 Independent Republican 1R Arizona R+7 Republican Republican 5R, 4D Arkansas R+14 Republican Republican 4R California D+9 Democratic Democratic 39D, 14R Colorado D+1 Democratic Both 4R, 3D Connecticut D+7 Democratic Democratic 5D Delaware D+8 Democratic Democratic 1D Florida R+2 Republican Both 16R, 11D Georgia R+6 Republican Republican 10R, 4D Hawaii D+20 Democratic Democratic 2D Idaho R+18 Republican Republican 2R Illinois D+8 Republican Democratic 11D, 7R Indiana R+5 Republican Both 7R, 2D Iowa D+1 Republican Republican 3R, 1D Kansas R+12 Republican Republican 4R Kentucky R+13 Republican Republican 5R, 1D Louisiana R+12 Democratic Republican 5R, 1D Maine D+6 Republican Both* EVEN 1-1 Maryland D+10 Republican Democratic 7D, 1R Massachusetts D+10 Republican Democratic 9D Michigan D+4 Republican Democratic 9R, 5D Minnesota D+2 Democratic Democratic 5D, 3R Mississippi R+9 Republican Republican 3R, 1D Missouri R+5 Republican Both 6R, 2D Montana R+7 Democratic Both 1R Nebraska R+12 Republican Republican 3R Nevada D+2 Republican Both 3D, 1R New Hampshire D+1 Republican Democratic 2D New Jersey D+6 Republican Democratic 7D, 5R New Mexico D+4 Republican Democratic 2D, 1R New York D+11 Democratic Democratic 18D, 9R North Carolina R+3 Republican Republican 10R, 3D North Dakota R+10 Republican Both 1R Ohio R+1 Republican Both 12R, 4D Oklahoma R+19 Republican Republican 5R Oregon D+5 Democratic Democratic 4D, 1R Pennsylvania D+1 Democratic Both 13R, 5D Rhode Island D+11 Democratic Democratic 2D South Carolina R+8 Republican Republican 6R, 1D South Dakota R+10 Republican Republican 1R Tennessee R+12 Republican Republican 7R, 2D Texas R+10 Republican Republican 25R, 11D Utah R+22 Republican Republican 4R Vermont D+16 Republican Democratic* 1D Virginia EVEN Democratic Democratic 7R, 4D Washington D+5 Democratic Democratic 6D, 4R West Virginia R+13 Democratic Both 3R Wisconsin D+2 Republican Both 5R, 3D Wyoming R+22 Republican Republican 1R *An independent senator caucuses with the Democrats.

See also

• Psephology, the statistical analysis of elections.
• Political party strength in U.S. states

References

1. Wasserman, David (October 11, 2012). "House About PVI". The Cook Political Report. Retrieved November 17, 2012.
2. "Monopoly Politics". Center for Voting and Democracy. July 1997. Retrieved November 17, 2012.
3. "Cook Releases 2008 PVIs, With a Change SSPers Will Like". Swing State Project. April 9, 2009. Retrieved November 17, 2012.
4. "Partisan Voting Index, Districts of the 113th Congress" (PDF). The Cook Political Report. Retrieved September 23, 2014.
5. "Partisan Voter Index by State, 1994–2014" (PDF). The Cook Political Report. 2013. Retrieved December 23, 2014.

External links

• The Cook Political Report