DW-NOMINATE Program
Updated 6 January 2016


To see how DW-NOMINATE works, download the program (DW-NOMINATE.FOR), the "control card" file (DW-NOMSTART.DAT), and the Senate Roll Call data files below:

DW-NOMINATE Program Source Code (FORTRAN -- DW-NOMINATE.FOR)
Control Card File for Senate (DW-NOMSTART.DAT)
Control Card File for House (DW-NOMSTART_HOUSE_21.DAT -- Rename this to DW-NOMSTART.DAT when the House is Scaled!!
1 to 110th Senate Roll Call Data (S01110_1ST.VT3)
1 to 110th Senate Transposed Roll Call Data (ST01110_1ST.VT3)
1 to 110th House Roll Call Data (H01110_PRES_1ST.VT3)
1 to 110th House Transposed Roll Call Data (HT01110_PRES_1ST.VT3)
Two Dimensional Starting Coordinates for Senate Roll Calls, 1 to 110th Senates (SC01110B21.DAT -- 47,222 lines)
Two Dimensional Starting Coordinates for Senators, 1 to 110th Senates (SL01110B21.DAT -- 8,746 lines)
Two Dimensional Starting Coordinates for House Roll Calls, 1 to 110th Houses (HC01110B21_PRES.DAT -- 48,381 lines)
Two Dimensional Starting Coordinates for Representatives, 1 to 110th Houses (HL01110B21_PRES.DAT -- 36,177 lines)
NSENATE3_2008.NUM -- File Containing Number of Senators and Roll Calls by Congress (Read by DW-NOMINATE)
NHOUSE3_2008.NUM -- File Containing Number of Representatives and Roll Calls by Congress (Read by DW-NOMINATE)

and place them in the same folder on a WINTEL machine. DW-NOMSTART.DAT for the Senate looks like this:
SC01110B21.DAT           Starting Values for Roll Call Coordinates
SC01110C21.DAT           Output File for Roll Call Coordinates
SL01110B21.DAT           Starting Values for Legislator Coordinates
SL01110C21.DAT           Output File for Roll Call Coordinates
NSENATE3_2008.NUM        File With the Number of Legislators and Roll Calls For Each Congress
S01110_1ST.VT3           Roll Calls Stacked by Congress
ST01110_1ST.VT3          Transposed Roll Call Matrix
NOMINAL DYNAMIC-WEIGHTED MULTIDIMENSIONAL UNFOLDING  Title
    2    1    1  110    2    5   Number Dimensions; Model (0=Constant, 1=Dynamic); 1st Congress; Last Congress; First iteration value; Last iteration value
  5.9539  0.3463                 Starting Values for Beta and W_2
In the listing above do not change the relative spacing of the control parameters in the last two lines!. The First iteration value of "2" is used because "1" performs an OC analysis to get better starting values for the roll call parameters. The Last iteration value of "5" simply means that the program iterates a total of four times -- 2, 3, 4, 5.

The output file names can be anything the user wants but they should reflect what period is being scaled and the model being used for bookkeeping purposes. For example, here is what DW-NOMSTART.DAT looks like if only the 80th to the 110th Senates are scaled using the two-dimensional linear model:
SC01110B21.DAT
SC80110C21.DAT
SL01110B21.DAT
SL80110C21.DAT
NSENATE3_2008.NUM
S01110_1ST.VT3
ST01110_1ST.VT3
NOMINAL DYNAMIC-WEIGHTED MULTIDIMENSIONAL UNFOLDING 
    2    1   80  110    2    5
  5.9539  0.3463
Note that the " 1" (or 00001) has changed to "80" (or 00080) and the two output files have been changed accordingly.

Below is a Zip file with all the input and output files associated with this run:

SENATE_80-110_EXAMPLE.ZIP

Note that DW-NOMINATE outputs the coordinates for the roll calls and the legislators for each iteration. Because of the way the program does its bookkeeping, it stacks each iteration on top of one another so that the final iteration -- the final estimated coordinates -- is on the bottom. In addition, even if, as in the example above, a contiguous subset of the 110 Congresses is scaled, the program outputs coordinates for all legislators and roll calls. The roll calls and legislators not in the selected contiguous set of Congresses will simply show the starting values and zeroes in other fields. These can be discarded. For example, the file SL80110C21.DAT will have 8,746*4 = 34,984 lines of which the bottom 3,162 lines are the estimated coordinates for Senators in Senates 80 through 110. For the roll call file, SC80110C21.DAT, it will have 47,222*4 = 188,888 lines of which the bottom 20,246 lines are the estimated coordinates for the roll calls in Senates 80 through 110.

Here is a another example of what DW-NOMSTART.DAT looks like if only the 1st to the 40th Senates are scaled using the one-dimensional linear model:
SC01110B21.DAT
SC01040C21.DAT
SL01110B21.DAT
SL01040C21.DAT
NSENATE3_2008.NUM
S01110_1ST.VT3
ST01110_1ST.VT3
NOMINAL DYNAMIC-WEIGHTED MULTIDIMENSIONAL UNFOLDING 
    1    1    1   40    2    5
  5.9539  0.3463
Note that the " 110" (or 00110) in the orginal DW-NOMSTART.DAT file has changed to " 40" (or 00040) and the two output files have been changed accordingly.

Below is a Zip file with all the input and output files associated with this run:

SENATE_1-40_EXAMPLE.ZIP

In this example, the file SL01040C21.DAT will have 8,746*4 = 34,984 lines of which lines 26,239 to 28,225 are the estimated coordinates for Senators in Senates 1 through 40. For the roll call file, SC01040C21.DAT, it will have 47,222*4 = 188,888 lines of which lines 141,667 to 155,022 are the estimated coordinates for the roll calls in Senates 1 through 40.



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