- Cook Partisan Voting Index
The Cook Partisan Voting Index (CPVI), sometimes referred to as simply the Partisan Voting Index (PVI), is a measurement of how strongly an American congressional district or state leans toward one political party compared to the nation as a whole. It was developed in 1997 by Charlie Cook of the Cook Political Report, a nonpartisan political newsletter, working with Polidata, a political statistics analysis firm.
The index for each congressional district is derived by averaging its results from the prior two presidential elections and comparing them to national results. The index indicates which party's candidate was more successful in that district, as well as the number of percentage points by which its results exceeded the national average. The index is formatted as a letter followed by a plus sign and then a number; in a district whose CPVI score is R+2, a generic Republican presidential candidates would be expected to receive 2 percentage points more votes than the national average. Likewise, a CPVI score of D+3 shows that a generic Democratic candidate would be expected to receive 3 percentage points more votes than the national average.
List of PVIs
The most Democratic congressional districts in the country are New York's 15th and 16th at D+41, while the most Republican districts are Alabama's 6th and Texas's 13th with a PVI of R+29. As for states as a whole, Utah and Wyoming are the most Republican at R+20, and Vermont is the most Democratic at D+13 (D+39 for the District of Columbia, which is not a state and lacks voting representation in Congress but which has three electoral votes in Presidential elections).
The most Republican congressional district to be represented by a Democrat is Utah's 2nd, which has a Cook PVI of R+15. The district is represented by Jim Matheson. The most Democratic congressional district to be represented by a Republican is Illinois's 10th, which has a PVI of D+6. The district is represented by Bob Dold.
As a result of the 2010 elections, there are 18 Democratic-leaning House districts represented by Republicans (up from 8 before the election) and 17 Republican-leaning House districts represented by Democrats (down from 77 before the election). This represents a total of 35 out of 435 Representatives from districts with a PVI opposite to their own party. Just one district represented by Republicans has a Cook PVI greater than D+5; 8 districts represented by Democrats have Cook PVIs greater than R+5.
In the Senate, the most Republican-leaning state to have a Democratic senator is a tie between Alaska, with Democrat Mark Begich, and Nebraska, with Democrat Ben Nelson. The most Republican-leaning state to have two Democratic senators is West Virginia, with Democrats Jay Rockefeller and Joe Manchin. The most Democratic-leaning state to have a Republican senator is Massachusetts, with Republican Scott Brown. The most Democratic-leaning state to have two Republican Senators is Maine, with Republicans Olympia Snowe and Susan Collins. There are 19 Democratic senators from Republican-leaning states and 5 Republican senators from Democratic-leaning states, for a total of 24 out of 100 senators from states with a PVI opposite to their own party.
Six Republican-leaning states (the most Republican being Kentucky at R+10) have governors from the Democratic Party; eight Democratic leaning states (the most Democratic being Maine at D+5) have governors from the Republican party.
Colorado is the only state with an even PVI. Its House of Representatives delegation consists of four Republicans and three Democrats. Minnesota, with a PVI of D+2, is the only state with an evenly split (4-4) House delegation. It has two Republican Representatives in districts that lean Democratic, and two Democratic Representatives in one district that leans Republican and in its one even district. Massachusetts has the largest number of Representatives (10) of the seven states that have entirely Democratic delegations; Kansas has the largest number of Representatives (4) of the nine 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
According to the Cook Political Report for the 110th U.S. Congress, calculated according to the results of the 2004 and the 2008 U.S. presidential elections. The party representations are based on the winners of the 2010 U.S. House elections. There are 235 districts that lean Republican, 192 districts that lean Democratic and 9 districts that are even.
State District PVI Party of
Alabama 1st R+14 Republican Alabama 2nd R+16 Republican Alabama 3rd R+9 Republican Alabama 4th R+26 Republican Alabama 5th R+12 Republican Alabama 6th R+29 Republican Alabama 7th D+18 Democratic Alaska At-large R+13 Republican Arizona 1st R+6 Republican Arizona 2nd R+13 Republican Arizona 3rd R+9 Republican Arizona 4th D+13 Democratic Arizona 5th R+5 Republican Arizona 6th R+15 Republican Arizona 7th D+6 Democratic Arizona 8th R+4 Democratic Arkansas 1st R+8 Republican Arkansas 2nd R+5 Republican Arkansas 3rd R+16 Republican Arkansas 4th R+7 Democratic California 1st D+13 Democratic California 2nd R+11 Republican California 3rd R+6 Republican California 4th R+10 Republican California 5th D+15 Democratic California 6th D+23 Democratic California 7th D+19 Democratic California 8th D+35 Democratic California 9th D+37 Democratic California 10th D+11 Democratic California 11th R+1 Democratic California 12th D+23 Democratic California 13th D+22 Democratic California 14th D+21 Democratic California 15th D+15 Democratic California 16th D+16 Democratic California 17th D+19 Democratic California 18th D+4 Democratic California 19th R+9 Republican California 20th D+5 Democratic California 21st R+13 Republican California 22nd R+16 Republican California 23rd D+12 Democratic California 24th R+4 Republican California 25th R+6 Republican California 26th R+3 Republican California 27th D+13 Democratic California 28th D+23 Democratic California 29th D+14 Democratic California 30th D+18 Democratic California 31st D+29 Democratic California 32nd D+15 Democratic California 33rd D+35 Democratic California 34th D+22 Democratic California 35th D+31 Democratic California 36th D+12 Democratic California 37th D+26 Democratic California 38th D+18 Democratic California 39th D+12 Democratic California 40th R+8 Republican California 41st R+10 Republican California 42nd R+10 Republican California 43rd D+13 Democratic California 44th R+6 Republican California 45th R+3 Republican California 46th R+6 Republican California 47th D+4 Democratic California 48th R+6 Republican California 49th R+10 Republican California 50th R+3 Republican California 51st D+8 Democratic California 52nd R+9 Republican California 53rd D+14 Democratic Colorado 1st D+21 Democratic Colorado 2nd D+11 Democratic Colorado 3rd R+5 Republican Colorado 4th R+6 Republican Colorado 5th R+14 Republican Colorado 6th R+8 Republican Colorado 7th D+4 Democratic Connecticut 1st D+13 Democratic Connecticut 2nd D+6 Democratic Connecticut 3rd D+9 Democratic Connecticut 4th D+5 Democratic Connecticut 5th D+2 Democratic Delaware At-large D+7 Democratic District of Columbia At-large D+39 Democratic Florida 1st R+21 Republican Florida 2nd R+6 Republican Florida 3rd D+18 Democratic Florida 4th R+17 Republican Florida 5th R+9 Republican Florida 6th R+10 Republican Florida 7th R+7 Republican Florida 8th R+2 Republican Florida 9th R+6 Republican Florida 10th R+1 Republican Florida 11th D+11 Democratic Florida 12th R+6 Republican Florida 13th R+6 Republican Florida 14th R+11 Republican Florida 15th R+6 Republican Florida 16th R+5 Republican Florida 17th D+34 Democratic Florida 18th R+3 Republican Florida 19th D+15 Democratic Florida 20th D+13 Democratic Florida 21st R+5 Republican Florida 22nd D+1 Republican Florida 23rd D+28 Democratic Florida 24th R+4 Republican Florida 25th R+5 Republican Georgia 1st R+16 Republican Georgia 2nd D+1 Democratic Georgia 3rd R+19 Republican Georgia 4th D+24 Democratic Georgia 5th D+26 Democratic Georgia 6th R+19 Republican Georgia 7th R+16 Republican Georgia 8th R+10 Republican Georgia 9th R+28 Republican Georgia 10th R+15 Republican Georgia 11th R+20 Republican Georgia 12th D+1 Democratic Georgia 13th D+15 Democratic Hawaii 1st D+11 Democratic Hawaii 2nd D+14 Democratic Idaho 1st R+18 Republican Idaho 2nd R+17 Republican Illinois 1st D+34 Democratic Illinois 2nd D+36 Democratic Illinois 3rd D+11 Democratic Illinois 4th D+32 Democratic Illinois 5th D+19 Democratic Illinois 6th EVEN Republican Illinois 7th D+35 Democratic Illinois 8th R+1 Republican Illinois 9th D+20 Democratic Illinois 10th D+6 Republican Illinois 11th R+1 Republican Illinois 12th D+3 Democratic Illinois 13th R+1 Republican Illinois 14th R+1 Republican Illinois 15th R+6 Republican Illinois 16th R+2 Republican Illinois 17th D+3 Republican Illinois 18th R+6 Republican Illinois 19th R+9 Republican Indiana 1st D+8 Democratic Indiana 2nd R+2 Democratic Indiana 3rd R+14 Republican Indiana 4th R+14 Republican Indiana 5th R+17 Republican Indiana 6th R+10 Republican Indiana 7th D+14 Democratic Indiana 8th R+8 Republican Indiana 9th R+6 Republican Iowa 1st D+5 Democratic Iowa 2nd D+7 Democratic Iowa 3rd D+1 Democratic Iowa 4th EVEN Republican Iowa 5th R+9 Republican Kansas 1st R+23 Republican Kansas 2nd R+9 Republican Kansas 3rd R+3 Republican Kansas 4th R+14 Republican Kentucky 1st R+15 Republican Kentucky 2nd R+15 Republican Kentucky 3rd D+2 Democratic Kentucky 4th R+14 Republican Kentucky 5th R+16 Republican Kentucky 6th R+9 Democratic Louisiana 1st R+24 Republican Louisiana 2nd D+25 Democratic Louisiana 3rd R+12 Republican Louisiana 4th R+11 Republican Louisiana 5th R+14 Republican Louisiana 6th R+10 Republican Louisiana 7th R+14 Republican Maine 1st D+8 Democratic Maine 2nd D+3 Democratic Maryland 1st R+13 Republican Maryland 2nd D+7 Democratic Maryland 3rd D+6 Democratic Maryland 4th D+31 Democratic Maryland 5th D+11 Democratic Maryland 6th R+13 Republican Maryland 7th D+25 Democratic Maryland 8th D+21 Democratic Massachusetts 1st D+14 Democratic Massachusetts 2nd D+9 Democratic Massachusetts 3rd D+9 Democratic Massachusetts 4th D+14 Democratic Massachusetts 5th D+8 Democratic Massachusetts 6th D+7 Democratic Massachusetts 7th D+15 Democratic Massachusetts 8th D+32 Democratic Massachusetts 9th D+11 Democratic Massachusetts 10th D+5 Democratic Michigan 1st R+3 Republican Michigan 2nd R+7 Republican Michigan 3rd R+6 Republican Michigan 4th R+3 Republican Michigan 5th D+11 Democratic Michigan 6th EVEN Republican Michigan 7th R+2 Republican Michigan 8th R+2 Republican Michigan 9th D+2 Democratic Michigan 10th R+5 Republican Michigan 11th EVEN Republican Michigan 12th D+12 Democratic Michigan 13th D+31 Democratic Michigan 14th D+34 Democratic Michigan 15th D+13 Democratic Minnesota 1st R+1 Democratic Minnesota 2nd R+4 Republican Minnesota 3rd EVEN Republican Minnesota 4th D+13 Democratic Minnesota 5th D+23 Democratic Minnesota 6th R+7 Republican Minnesota 7th R+5 Democratic Minnesota 8th D+3 Republican Mississippi 1st R+14 Republican Mississippi 2nd D+12 Democratic Mississippi 3rd R+15 Republican Mississippi 4th R+20 Republican Missouri 1st D+27 Democratic Missouri 2nd R+9 Republican Missouri 3rd D+7 Democratic Missouri 4th R+14 Republican Missouri 5th D+10 Democratic Missouri 6th R+7 Republican Missouri 7th R+17 Republican Missouri 8th R+15 Republican Missouri 9th R+9 Republican Montana At-large R+7 Republican Nebraska 1st R+11 Republican Nebraska 2nd R+6 Republican Nebraska 3rd R+24 Republican Nevada 1st D+10 Democratic Nevada 2nd R+5 Republican Nevada 3rd D+2 Republican New Hampshire 1st EVEN Republican New Hampshire 2nd D+3 Republican New Jersey 1st D+12 Democratic New Jersey 2nd D+1 Republican New Jersey 3rd R+1 Republican New Jersey 4th R+6 Republican New Jersey 5th R+7 Republican New Jersey 6th D+8 Democratic New Jersey 7th R+3 Republican New Jersey 8th D+10 Democratic New Jersey 9th D+9 Democratic New Jersey 10th D+33 Democratic New Jersey 11th R+7 Republican New Jersey 12th D+5 Democratic New Jersey 13th D+21 Democratic New Mexico 1st D+5 Democratic New Mexico 2nd R+6 Republican New Mexico 3rd D+7 Democratic New York 1st EVEN Democratic New York 2nd D+4 Democratic New York 3rd R+4 Republican New York 4th D+6 Democratic New York 5th D+12 Democratic New York 6th D+36 Democratic New York 7th D+26 Democratic New York 8th D+22 Democratic New York 9th D+5 Republican New York 10th D+38 Democratic New York 11th D+38 Democratic New York 12th D+33 Democratic New York 13th R+4 Republican New York 14th D+26 Democratic New York 15th D+41 Democratic New York 16th D+41 Democratic New York 17th D+18 Democratic New York 18th D+9 Democratic New York 19th R+3 Republican New York 20th R+2 Republican New York 21st D+6 Democratic New York 22nd D+6 Democratic New York 23rd R+1 Democratic New York 24th R+2 Republican New York 25th D+3 Republican New York 26th R+6 Democratic New York 27th D+4 Democratic New York 28th D+15 Democratic New York 29th R+5 Republican North Carolina 1st D+9 Democratic North Carolina 2nd R+2 Republican North Carolina 3rd R+16 Republican North Carolina 4th D+8 Democratic North Carolina 5th R+15 Republican North Carolina 6th R+18 Republican North Carolina 7th R+5 Democratic North Carolina 8th R+2 Democratic North Carolina 9th R+11 Republican North Carolina 10th R+17 Republican North Carolina 11th R+6 Democratic North Carolina 12th D+16 Democratic North Carolina 13th D+5 Democratic North Dakota At-large R+10 Republican Ohio 1st D+1 Republican Ohio 2nd R+13 Republican Ohio 3rd R+5 Republican Ohio 4th R+15 Republican Ohio 5th R+9 Republican Ohio 6th R+2 Republican Ohio 7th R+7 Republican Ohio 8th R+14 Republican Ohio 9th D+10 Democratic Ohio 10th D+8 Democratic Ohio 11th D+32 Democratic Ohio 12th D+1 Republican Ohio 13th D+5 Democratic Ohio 14th R+3 Republican Ohio 15th D+1 Republican Ohio 16th R+4 Republican Ohio 17th D+12 Democratic Ohio 18th R+7 Republican Oklahoma 1st R+16 Republican Oklahoma 2nd R+14 Democratic Oklahoma 3rd R+24 Republican Oklahoma 4th R+18 Republican Oklahoma 5th R+13 Republican Oregon 1st D+8 Democratic Oregon 2nd R+10 Republican Oregon 3rd D+19 Democratic Oregon 4th D+2 Democratic Oregon 5th D+1 Democratic Pennsylvania 1st D+35 Democratic Pennsylvania 2nd D+38 Democratic Pennsylvania 3rd R+3 Republican Pennsylvania 4th R+6 Democratic Pennsylvania 5th R+9 Republican Pennsylvania 6th D+4 Republican Pennsylvania 7th D+3 Republican Pennsylvania 8th D+2 Republican Pennsylvania 9th R+17 Republican Pennsylvania 10th R+8 Republican Pennsylvania 11th D+4 Republican Pennsylvania 12th R+1 Democratic Pennsylvania 13th D+7 Democratic Pennsylvania 14th D+19 Democratic Pennsylvania 15th D+2 Republican Pennsylvania 16th R+8 Republican Pennsylvania 17th R+6 Democratic Pennsylvania 18th R+6 Republican Pennsylvania 19th R+12 Republican Rhode Island 1st D+13 Democratic Rhode Island 2nd D+9 Democratic South Carolina 1st R+10 Republican South Carolina 2nd R+9 Republican South Carolina 3rd R+17 Republican South Carolina 4th R+15 Republican South Carolina 5th R+7 Republican South Carolina 6th D+12 Democratic South Dakota At-large R+9 Republican Tennessee 1st R+21 Republican Tennessee 2nd R+16 Republican Tennessee 3rd R+13 Republican Tennessee 4th R+13 Republican Tennessee 5th D+3 Democratic Tennessee 6th R+13 Republican Tennessee 7th R+18 Republican Tennessee 8th R+6 Republican Tennessee 9th D+23 Democratic Texas 1st R+21 Republican Texas 2nd R+13 Republican Texas 3rd R+14 Republican Texas 4th R+21 Republican Texas 5th R+17 Republican Texas 6th R+15 Republican Texas 7th R+13 Republican Texas 8th R+25 Republican Texas 9th D+22 Democratic Texas 10th R+10 Republican Texas 11th R+28 Republican Texas 12th R+16 Republican Texas 13th R+29 Republican Texas 14th R+18 Republican Texas 15th D+3 Democratic Texas 16th D+10 Democratic Texas 17th R+20 Republican Texas 18th D+24 Democratic Texas 19th R+26 Republican Texas 20th D+8 Democratic Texas 21st R+14 Republican Texas 22nd R+13 Republican Texas 23rd R+4 Republican Texas 24th R+11 Republican Texas 25th D+6 Democratic Texas 26th R+13 Republican Texas 27th R+2 Republican Texas 28th EVEN Democratic Texas 29th D+8 Democratic Texas 30th D+27 Democratic Texas 31st R+14 Republican Texas 32nd R+8 Republican Utah 1st R+21 Republican Utah 2nd R+15 Democratic Utah 3rd R+26 Republican Vermont At-large D+13 Democratic Virginia 1st R+7 Republican Virginia 2nd R+5 Republican Virginia 3rd D+20 Democratic Virginia 4th R+4 Republican Virginia 5th R+5 Republican Virginia 6th R+12 Republican Virginia 7th R+9 Republican Virginia 8th D+16 Democratic Virginia 9th R+11 Republican Virginia 10th R+2 Republican Virginia 11th D+2 Democratic Washington 1st D+9 Democratic Washington 2nd D+3 Democratic Washington 3rd EVEN Republican Washington 4th R+13 Republican Washington 5th R+7 Republican Washington 6th D+5 Democratic Washington 7th D+31 Democratic Washington 8th D+3 Republican Washington 9th D+5 Democratic West Virginia 1st R+9 Republican West Virginia 2nd R+8 Republican West Virginia 3rd R+6 Democratic Wisconsin 1st R+2 Republican Wisconsin 2nd D+15 Democratic Wisconsin 3rd D+4 Democratic Wisconsin 4th D+22 Democratic Wisconsin 5th R+12 Republican Wisconsin 6th R+4 Republican Wisconsin 7th D+3 Republican Wisconsin 8th R+2 Republican Wyoming At-large R+20 Republican
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.
State District PVI Party of
American Samoa At-large N/A Democratic Guam At-large N/A Democratic Northern Mariana Islands At-large N/A Democratic Puerto Rico At-large N/A Democratic United States Virgin Islands At-large N/A Democratic
Based on the 2004 U.S. presidential election and the 2008 U.S. presidential election. The Senate party representations are based on the winners of the 2010 U.S. Senate elections. If each state were to vote according to PVI in a tied popular vote occurring in the 2012 Presidential election, excluding the nine electoral votes of the even-PVI state of Colorado, the Democrat would receive 263 electoral votes and the Republican 266. Colorado would decide the election, resulting in a 272-266 Democratic win or a 275-263 Republican win.
State PVI Governor Party
Alabama R+13 Republican Republican 6R, 1D Alaska R+13 Republican BOTH 1R Arizona R+6 Republican Republican 5R, 3D Arkansas R+9 Democratic BOTH 3R, 1D California D+7 Democratic Democratic 34D, 19R Colorado EVEN Democratic Democratic 4R, 3D Connecticut D+7 Democratic Democratic 5D Delaware D+7 Democratic Democratic 1D Florida R+2 Republican BOTH 19R, 6D Georgia R+7 Republican Republican 8R, 5D Hawaii D+12 Democratic Democratic 2D Idaho R+17 Republican Republican 2R Illinois D+8 Democratic BOTH 11R, 8D Indiana R+6 Republican Republican 6R, 3D Iowa D+1 Republican BOTH 3D, 2R Kansas R+12 Republican Republican 4R Kentucky R+10 Democratic Republican 4R, 2D Louisiana R+10 Republican BOTH 6R, 1D Maine D+5 Republican Republican 2D Maryland D+9 Democratic Democratic 6D, 2R Massachusetts D+12 Democratic BOTH 10D Michigan D+4 Republican Democratic 9R, 5D Minnesota D+2 Democratic Democratic EVEN 4-4 Mississippi R+10 Republican Republican 3R, 1D Missouri R+3 Democratic BOTH 6R, 3D Montana R+7 Democratic Democratic 1R Nebraska R+13 Republican BOTH 3R Nevada D+1 Republican BOTH 2R, 1D New Hampshire D+2 Democratic BOTH 2R New Jersey D+4 Republican Democratic 7D, 6R New Mexico D+2 Republican Democratic 2D, 1R New York D+10 Democratic Democratic 21D, 8R North Carolina R+4 Democratic BOTH 7D, 6R North Dakota R+10 Republican BOTH 1R Ohio R+1 Republican BOTH 13R, 5D Oklahoma R+17 Republican Republican 4R, 1D Oregon D+4 Democratic Democratic 4D, 1R Pennsylvania D+2 Republican BOTH 12R, 7D Rhode Island D+11 Independent Democratic 2D South Carolina R+8 Republican Republican 5R, 1D South Dakota R+9 Republican BOTH 1R Tennessee R+9 Republican Republican 7R, 2D Texas R+10 Republican Republican 23R, 9D Utah R+20 Republican Republican 2R, 1D Vermont D+13 Democratic Democratic 1D Virginia R+2 Republican Democratic 8R, 3D Washington D+5 Democratic Democratic 5D, 4R West Virginia R+8 Democratic Democratic 2R, 1D Wisconsin D+2 Republican BOTH 5R, 3D Wyoming R+20 Republican Republican 1R
By state legislative districts
In 2011, a Yale freshman extended this analysis to legislative districts, referring to it as the "Legislative District Index."
- ^ Remsen, Nancy (July 16, 2011). "Prognosticating Prodigy". Burlington Free Press (Burlington, Vermont): pp. 1A. http://www.burlingtonfreepress.com/apps/pbcs.dll/article?AID=2011110716002.
- "Partisan Voting Index Districts of the 111th Congress, Arranged by State/District". The Cook Political Report. 2009-04-10. http://www.cookpolitical.com/sites/default/files/pvistate.pdf.
Wikimedia Foundation. 2010.