Common Space Data

6 January 2015

Common Space Scores Congresses 75 - 113

Common Space Scores (Text File)
Common Space Scores (Excel File)
Common Space Scores (Stata 13 File)
Common Space Scores (Stata 12 File)

BL75113.DAT are W-NOMINATE coordinates for the 75th through the 113th (2014) Houses and Senates adjusted so that the the House and Senate members and the Presidents are in the same space. There is one record for each legislator and each Congress for this time period (n=21,144, 1937-2014).

The format for BL75113.DAT is:

          1.  Congress Number 75 - 113
          2.  ICPSR ID Number:  5 digit code assigned by the ICPSR as 
                                corrected by Howard Rosenthal and myself.
          3.  State Code:  2 digit ICPSR State Code (99 if President)
          4.  Congress District Number (Senate and President = 0)
          5.  Name of State
          6.  Party Code:  100 = Dem., 200 = Repub. (See PARTY3.HTM)
          7.  Name
          8.  1st Dimension Coordinate
          9.  2nd Dimension Coordinate
         10.  Indicator For Chamber
                            0 = House
                            1 = Senate
                            2 = President (83 - 113)
The W-NOMINATE coordinates of all members serving in both the House and Senate from 1937 - 2014 (Congresses 75 - 113) were used to estimate the common space coordinates. Each legislator is assigned a single coordinate throughout his or her career so that members who served in both chambers will have the same coordinate in both. The 1st dimension coordinates correlate with the corresponding DW-NOMINATE coordinates at .95 or higher for all Houses and Senates. All Houses and Senates after the 80th Congress correlate at .96 and higher for both dimensions.

The Presidents from Eisenhower through Clinton were scaled using the CQ Presidential Support Roll Calls in W-NOMINATE. See "Veto Power and Legislation: An Empirical Analysis of Executive and Legislative Bargaining from 1961-1986," Journal of Law, Economics, and Organization, 11, 1995, 282-312 (with Nolan M. McCarty), for an analysis of these W-NOMINATE scores. Their W-NOMINATE scores were treated like any other member of the House and Senate for the purposes of fitting them into the common space.

Note that the common space coordinates are adjusted so that the two dimensions are equally salient and lie within a unit circle. The first dimension W-NOMINATE and DW-NOMINATE scores correctly classify about 85 percent of roll call choices through this period and the second dimension typically picks up an additional 2 to 5 percent.

The state, congressional district, and party codes used in the common space coordinate file correspond to Ken Martis's The Historical Atlas of Political Parties in the United States Congress. Howard and I consider Martis's Atlas to be the best source of information about party affiliation of members of Congress so that our data base can be considered to be very "clean". Congresses 1 - 100 have been extensively checked by ourselves and other scholars. Congresses 101-113 have also been checked but cannot be considered to be completely "clean". If you find errors, please send E-Mail to Keith Poole -- -- so that corrections can be made.

The file PARTY3.HTM contains the dictionary for the party codes. Please cite Ken Martis's atlas as the original source if you use these codes in any way.

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