109th Senate Rank Ordering

Jeff Lewis and Keith Poole

31 December 2006


Below is the rank ordering of the 109th Senate. This ordering was produced by the Optimal Classification (OC) algorithm described in:

"Non-Parametric Unfolding of Binary Choice Data." Political Analysis, 8:211-237, 2000.

The scaling program that performs the rank ordering along with some examples can be downloaded from:

Optimal Classification (OC) Scaling Program Page

To see how OC works in one dimension, go to this page:

How Optimal Classification Works in One Dimension

To see how OC works in two or more dimensions, go to this page:

How Optimal Classification Works in Two or More Dimensions (Under Construction)

There were 645 roll calls cast in the 109th Senate of which 544 roll calls had at least 0.5% or better in the minority and were used in the scaling. The rank ordering is based upon these 544 roll calls. Note that tied ranks are allowed.

The overall correct classification is 92.0% with an aggregate proportional reduction in error of (APRE) .767. In the ordering below, the number just to the right of the Senator's name is the classification error and the number to the right of that is the total number of roll calls cast by the Senator. For example, placing Senator Kennedy at the tied rank of 5.5 only resulted in 15 classification errors out of a total of 530 votes cast. The proportion correct is 515/530 = .972 (which is shown just to the left of the rank).

The two parties are perfectly separated in the liberal-conservative ordering.

(To obtain the 109th Senate Roll Call Matrix go to the Data Download Page on this Server. The matrix is available in text and as a Stata 7 file. )

(These roll calls were also used to forecast the vote on John Roberts to be Chief Justice of the Supreme Court.)

(Two dimensional spatial maps of the last 50 Senate Roll calls are displayed here and the last 50 House Roll calls are displayed here.)

(Ideological Rank Orderings of Recent Congresses: 110th House and Iraq War Vote, 110th House, 110th Senate, 109th House, 108th Senate, 108th House, 107th Senate, 107th House. For Parametric Measures go to the Data Download Page. The 109th Senate is the most polarized Senate since the end of Reconstruction.)

 109 49309 25  WISCONS D FEINGOLD      55  536   0.897   1.000
 109 14230 31  IOWA    D HARKIN        36  540   0.933   2.500
 109 14307  6  VERMONT D LEAHY         35  542   0.935   2.500
 109 15011 71  CALIFOR D BOXER         33  521   0.937   4.000
 109 10808  3  MASSACH D KENNEDY  ED   15  530   0.972   5.500
 109 40104 12  NEW JER D CORZINE       11  199   0.945   5.500
 109 14914 12  NEW JER D LAUTENBERG    25  537   0.953   7.000
 109 13039 52  MARYLAN D SARBANES      20  542   0.963   8.000
 109 29142  5  RHODE I D REED          28  543   0.948   9.000
 109 94240  6  VERMONT I JEFFORDS      49  517   0.905  10.000
 109 14400 82  HAWAII  D AKAKA         31  535   0.942  11.000
 109  4812 82  HAWAII  D INOUYE        40  488   0.918  12.500
 109 14709 23  MICHIGA D LEVIN  CARL   29  542   0.946  12.500
 109 15021 21  ILLINOI D DURBIN        21  538   0.961  14.000
 109 40101 33  MINNESO D DAYTON        36  516   0.930  15.000
 109 49308 73  WASHING D MURRAY        40  539   0.926  16.000
 109 14213  1  CONNECT D DODD          41  520   0.921  17.500
 109 39310 73  WASHING D CANTWELL      41  537   0.924  17.500
 109 14871 72  OREGON  D WYDEN         51  542   0.906  19.000
 109 29373 12  NEW JER D MENENDEZ      13  223   0.942  20.000
 109 40502 21  ILLINOI D OBAMA         30  538   0.944  21.000
 109 14440 52  MARYLAN D MIKULSKI      17  519   0.967  22.000
 109 49300 71  CALIFOR D FEINSTEIN     39  535   0.927  23.000
 109 14858 13  NEW YOR D SCHUMER       37  539   0.931  24.000
 109 40105 13  NEW YOR D CLINTON       32  532   0.940  25.000
 109 14920  3  MASSACH D KERRY  JOHN   31  526   0.941  26.000
 109 29732 23  MICHIGA D STABENOW      34  539   0.937  27.000
 109 49901 22  INDIANA D BAYH          48  537   0.911  28.000
 109 14101 11  DELAWAR D BIDEN         42  502   0.916  29.000
 109 14912 66  NEW MEX D BINGAMAN      57  529   0.892  30.500
 109 15704  1  CONNECT D LIEBERMAN     52  509   0.898  30.500
 109 15703 25  WISCONS D KOHL          39  541   0.928  32.000
 109 14922 56  WEST VI D ROCKEFELLER   28  434   0.935  33.000
 109 15054 65  NEVADA  D REID          33  543   0.939  34.000
 109 40500 62  COLORAD D SALAZAR       44  532   0.917  35.000
 109 14812 36  NORTH D D DORGAN        57  532   0.893  36.000
 109 15502 36  NORTH D D CONRAD        79  525   0.850  37.000
 109  1366 56  WEST VI D BYRD  ROBER   87  530   0.836  38.000
 109 15425 37  SOUTH D D JOHNSON       45  538   0.916  39.000
 109 14651 43  FLORIDA D NELSON        74  541   0.863  40.000
 109 49702 45  LOUISIA D LANDRIEU      66  530   0.875  41.000
 109 29305 42  ARKANSA D LINCOLN       36  540   0.933  42.000
 109 40301 42  ARKANSA D PRYOR         43  543   0.921  43.000
 109 14203 64  MONTANA D BAUCUS        62  530   0.883  44.000
 109 15015 11  DELAWAR D CARPER        56  542   0.897  45.000
 109 40103 35  NEBRASK D NELSON  BEN  106  542   0.804  46.000
 109 49905  5  RHODE I R CHAFEE        76  531   0.857  47.000
 109 14661  2  MAINE   R SNOWE         53  536   0.901  48.000
 109 49703  2  MAINE   R COLLINS       46  544   0.915  49.000
 109 14910 14  PENNSYL R SPECTER       70  531   0.868  50.000
 109 15020 24  OHIO    R DEWINE        65  543   0.880  51.000
 109 40302 33  MINNESO R COLEMAN       33  520   0.937  52.000
 109 49705 72  OREGON  R SMITH  GORD   48  539   0.911  53.000
 109 29369 34  MISSOUR R TALENT        61  544   0.888  54.000
 109 14506 22  INDIANA R LUGAR         48  538   0.911  55.000
 109 14712 40  VIRGINI R WARNER        46  537   0.914  56.000
 109 40300 81  ALASKA  R MURKOWSKI     27  531   0.949  57.000
 109 40501 43  FLORIDA R MARTINEZ      48  534   0.910  58.000
 109 49704 35  NEBRASK R HAGEL         52  537   0.903  59.000
 109 49903 24  OHIO    R VOINOVICH     69  539   0.872  60.000
 109 14103 66  NEW MEX R DOMENICI      24  519   0.954  61.000
 109 12109 81  ALASKA  R STEVENS       33  536   0.938  62.000
 109 49307 67  UTAH    R BENNETT       26  537   0.952  63.000
 109 14009 46  MISSISS R COCHRAN       23  537   0.957  64.000
 109 40304 54  TENNESS R ALEXANDER     43  536   0.920  65.000
 109 49502 54  TENNESS R FRIST         33  542   0.939  66.000
 109 49306 49  TEXAS   R HUTCHISON     47  542   0.913  67.000
 109 15501 34  MISSOUR R BOND          38  543   0.930  68.000
 109 15701 64  MONTANA R BURNS         33  531   0.938  69.000
 109 14852 32  KANSAS  R ROBERTS       30  536   0.944  70.000
 109 14503 67  UTAH    R HATCH         23  530   0.957  71.000
 109 29141 14  PENNSYL R SANTORUM      46  524   0.912  72.000
 109 14226 31  IOWA    R GRASSLEY      32  544   0.941  73.000
 109 29754 37  SOUTH D R THUNE         42  530   0.921  74.000
 109 40303 47  NORTH C R DOLE          36  538   0.933  75.000
 109 14031 46  MISSISS R LOTT          32  501   0.936  76.000
 109 29345 63  IDAHO   R CRAPO         29  542   0.946  77.000
 109 29918 45  LOUISIA R VITTER        46  530   0.913  78.500
 109 94659 41  ALABAMA R SHELBY        43  535   0.920  78.500
 109 14809 63  IDAHO   R CRAIG         39  539   0.928  80.000
 109 14921 51  KENTUCK R MCCONNELL     26  543   0.952  81.000
 109 29523 32  KANSAS  R BROWNBACK     50  535   0.907  82.000
 109 29148 40  VIRGINI R ALLEN         37  542   0.932  83.000
 109 29512 44  GEORGIA R CHAMBLISS     27  532   0.949  84.000
 109 29909 44  GEORGIA R ISAKSON       22  537   0.959  85.000
 109 29537 65  NEVADA  R ENSIGN        50  536   0.907  86.000
 109 15406 51  KENTUCK R BUNNING       26  530   0.951  87.000
 109 15424 53  OKLAHOM R INHOFE        44  536   0.918  88.000
 109 49706 68  WYOMING R ENZI          28  519   0.946  89.000
 109 40305 49  TEXAS   R CORNYN        36  538   0.933  90.000
 109 15633 68  WYOMING R THOMAS        33  521   0.937  91.000
 109 29108 62  COLORAD R ALLARD        38  542   0.930  92.000
 109 49700 41  ALABAMA R SESSIONS      29  542   0.946  93.000
 109 29566 48  SOUTH C R GRAHAM        62  525   0.882  94.000
 109 29555 53  OKLAHOM R COBURN        56  538   0.896  95.000
 109 29548 47  NORTH C R BURR          36  537   0.933  96.000
 109 29936 48  SOUTH C R DEMINT        26  538   0.952  97.000
 109 14826  4  NEW HAM R GREGG         63  536   0.882  98.000
 109 29740  4  NEW HAM R SUNUNU        61  529   0.885  99.000
 109 15039 61  ARIZONA R MCCAIN        99  505   0.804 100.000
 109 15429 61  ARIZONA R KYL           37  542   0.932 101.000


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