Aldrich-McKelvey 7-Point Issue Scale Program


ALDMCK.ZIP contains the following 6 files:

MCKALNEW.FOR -- FORTRAN program
MCKALNEW.EXE -- Compiled program that will run on any Pentium computer
LC1980.CTL -- "Control card" file that controls the operations of the program (see below)
LC1980V.DAT -- Example data file
LC1980X.DAT -- Output File for example
LC1980X.PRN -- Output File for example

MCKALNEW.FOR was originally written by Keith T. Poole at the University of Oregon in October 1978. This 1978 mainframe version was modified for use on IBM PCs by Keith T. Poole at Carnegie-Mellon University in November, 1986. This small memory version was updated in August of 1996.

For the theory of the program see:

Aldrich, John and Richard D. McKelvey. 1977. "A Method of Scaling with Applications to the 1968 and 1972 Presidential Elections." American Political Science Review, 71: 111-130.

Palfrey, Thomas R. and Keith T. Poole. 1987. "The Relationship Between Information, Ideology, and Voting Behavior." American Journal of Political Science, 31:511-530.

Poole, Keith T. 1998. "Recovering a Basic Space From a Set of Issue Scales." American Journal of Political Science, 42:954-993.

HOW TO USE THE ALDRICH-MCKELVEY SCALING PROGRAM

The program will prompt you for 4 files: a control card file; a data file; an output file; and an output file for the scaled individual coordinates. The control card file contains the parameters of the scaling--number of stimuli, format of the data file, names of the stimuli, and so on. The data file contains the individual responses to the stimuli. The output file contains all the relevant output from the scaling; and the coordinate file contains the scaled coordinates of the individuals.

Run the program from the command line by simply typing (what you should type is in red):

MCKALNEW
 Control Card File Name? LC1980.CTL
Data File Name? LC1980V.DAT
Output File Name? LC1980X.DAT
Coordinate Output File Name? LC1980X.PRN


The program reads LC1980.CTL and LC1980V.DAT and writes the output files to disk. This example is for the 1980 Pre-Election Liberal-Conservative 7-Point Scale. LC1980V.DAT was extracted from the ICPSR file NES1980.DAT for presentation purposes. Normally you should just write a format statement (see below) and read the overall survey file directly.

Control Card Setup

  1. Card 1: NQ, NRESP, NMISS, NLEFT 4I2

    NQ = The number of stimuli (maximum is 20).
    NRESP = The position of the respondent's self placement in the data (usually this is the first or last entry of a row of data so NRESP = 1 or NRESP = NQ+1). If the respondent self placements are not collected, set NRESP = 0.
    NMISS = The number of missing data values. If NMISS = 0, omit card 3 below.
    NLEFT = The number of the stimulus which should be the left-most on the underlying dimension. The stimuli are recovered only up to a linear transformation. This parameter simply allows you to multiply the scaled configuration by -1 so that the stimuli are "correctly" ordered. This parameter must be set to an integer between 0 and NQ. If 0 is selected, that is, if there is no obvious left-most stimulus, then the default is the first stimulus.

  2. Card 2: Format Statement

    This is a standard FORTRAN format statement for the data file. The program expects to read an integer (which identifies the individual case) and then the NQ or NQ+1 responses by the individual. The responses must be in F format--not integer format (see the example below). The format statement must not exceed 80 characters.

  3. Card 3: Missing Data Values

    These must be read in as F5.1 format (see the example below). Omit this card if NMISS is set to 0.

  4. Card 4 to NQ+4: Names For Stimuli

    One card per stimuli with a limit of 13 characters in the name. If NRESP¹0, then the last card should be the preferred name of the individuals in the survey (e.g. INDIV or RESPONDENT).

Example of control card setup: LC1980.CTL -- File for 1980 Pre-Election Liberal-Conservative 7-Point Scale 

 6 1 3 3
(1x,i6,3X,7f2.0)
  0.0  8.0  9.0
carter
reagan
kennedy                 (Note that NLEFT=3 because a good guess is that Ted
anderson                 Kennedy should be the furthest to the left on the
repub                    underlying scale.)
demo
indiv
Example of data file: LC1980V.DAT -- 1980 Pre-Election Liberal-Conservative 7-Point Scale (This data was taken from NES1980.DAT.) 


      1  0 6 2 6 1 7 5 5
      8  0 6 4 6 4 7 6 4
      9  1 6 3 6 3 3 6 2
     10  2 4 6 4 3 3 5 4
     11  2 5 7 2 5 5 7 5
     13  1 7 6 6 2 5 7 4
     14  6 4 3 6 2 5 6 3
     16  1 6 3 7 4 2 7 3
     17  0 4 5 3 5 2 8 8
     19  2 5 3 6 4 5 6 2
     20  1 4 2 6 1 3 5 3
     25  2 4 2 7 1 5 6 2
     27  0 4 3 5 4 4 4 4

     etc.

   1608  1 6 1 6 1 6 6 1
   1609  0 4 3 5 1 8 5 3
   1610  2 4 5 4 3 3 6 5
   1611  0 4 1 3 8 5 4 1
   1613  1 6 3 6 2 3 6 3
   1614  1 4 6 2 4 8 4 4


Example of Output file: LC1980X.DAT. 
 ******************************************************************************
 NUMBER OF CASES
       643       888  643 of 888 total respondents have complete responses
 MISSING CASES
 DEGENERATE--MISS  NOMISS
         0         3
   carte  reaga  kenne  ander  repub  demo 
      13     21     37    113     88     83 This just breaks down the missing data by stimulus
 ******************************************************************************
 X(XPRIMEX)-1XPRIME-NI MATRIX
   -465.8195
     46.9307   -378.5806
    129.1280     -3.1085   -399.4966
     90.6159     81.0773    107.4974   -456.9012
     59.0475    219.1423      9.6141     80.6484   -405.7944
    140.0980     34.5388    156.3660     97.0625     37.3420   -465.4069
 ******************************************************************************
 PERFORMANCE INDEX=    0
 EIGENVALUES
   -617.0778
   -606.2012
   -574.4373
   -546.4819
   -227.8011  This is the eigenvalue of interest
      0.0002
 ******************************************************************************
 ******************************************************************************
 STIMULUS COORDINATES  This is the eigenvector of interest
    carte    reaga    kenne    ander    repub    demo 
  -0.2316   0.5819  -0.4853  -0.0655   0.5173  -0.3168
This is computed directly from the data and normalized -- a check on the eigenvector
 STIMULUS COORDINATES RAW DATA 
  -0.1731   0.5715  -0.5209  -0.1098   0.5242  -0.2920
 ******************************************************************************
 CORRECTED GOODNESS OF FIT AND RAW FIT
      0.1416      0.4928
 ******************************************************************************
The negative weights are the respondents who see the space "backwards"!
 TOTAL CASES--NUMBER POSITIVE  NUMBER NEGATIVE 
      643            569               74
 ******************************************************************************
 R AND R-SQUARE
    0.8036    0.6457
This is simply a check on the estimation -- the individual betas are 
applied to the raw data and the means computed
 STIMULUS COORDINATES FROM COMPUTED BETA WEIGHTS 
    carte    reaga    kenne    ander    repub    demo     indiv
  -0.2316   0.5819  -0.4853  -0.0655   0.5173  -0.3168   0.1591
 STANDARD DEVIATIONS
   0.2753   0.3134   0.3407   0.3470   0.2837   0.2402   0.5274
 ******************************************************************************

                            HISTOGRAM FOR ALL INDIVIDUALS
                            MISSING CASES=    16
 -1.19/-1.14    0                                                         
 -1.14/-1.09    2  **                                                     
 -1.09/-1.04    0                                                         
 -1.04/-1.00    1  *                                                      
 -1.00/-0.95    3  ***                                                    
 -0.95/-0.90    2  **                                                     
 -0.90/-0.85    1  *                                                      
 -0.85/-0.81    6  ******                                                 
 -0.81/-0.76    4  ****                                                   
 -0.76/-0.71    8  #********                                              
 -0.71/-0.66    3  ***                                                    
 -0.66/-0.62    9  *********                                              
 -0.62/-0.57    7  *******                                                
 -0.57/-0.52    8  ********                                               
 -0.52/-0.47    6  #******                                                
 -0.47/-0.43   10  **********                                             
 -0.43/-0.38   17  *****************                                      
 -0.38/-0.33   14  #**************                                        
 -0.33/-0.28   15  ***************                                        
 -0.28/-0.24   19  *******************                                    
 -0.24/-0.19   16  ****************                                       
 -0.19/-0.14   18  ******************                                     
 -0.14/-0.09   25  #*************************                             
 -0.09/-0.05   25  *************************                              
 -0.05/ 0.00   21  *********************                                  
  0.00/ 0.05   48  ************************************************       
  0.05/ 0.09   32  ********************************                       
  0.09/ 0.14   25  *************************                              
  0.14/ 0.19   15  ***************                                        
  0.19/ 0.24   15  ***************                                        
  0.24/ 0.28   10  **********                                             
  0.28/ 0.33   13  *************                                          
  0.33/ 0.38   16  ****************                                       
  0.38/ 0.43   17  *****************                                      
  0.43/ 0.47   16  ****************                                       
  0.47/ 0.52    9  *********                                              
  0.52/ 0.57   20  ********************                                   
  0.57/ 0.62   16  ****************                                       
  0.62/ 0.66   21  *********************                                  
  0.66/ 0.71   14  **************                                         
  0.71/ 0.76   14  **************                                         
  0.76/ 0.81   27  #***************************                           
  0.81/ 0.85   20  ********************                                   
  0.85/ 0.90    9  #*********                                             
  0.90/ 0.95    9  *********                                              
  0.95/ 1.00    4  ****                                                   
  1.00/ 1.04    8  ********                                               
  1.04/ 1.09    3  ***                                                    
  1.09/ 1.14    3  ***                                                    
  1.14/ 1.19    3  ***                                                    

                            HISTOGRAM FOR INDIVIDUALS WITH POSITIVE WEIGHTS
                            MISSING CASES=    14
 -1.19/-1.14    0                                                         
 -1.14/-1.09    2  **                                                     
 -1.09/-1.04    0                                                         
 -1.04/-1.00    1  *                                                      
 -1.00/-0.95    3  ***                                                    
 -0.95/-0.90    2  **                                                     
 -0.90/-0.85    1  *                                                      
 -0.85/-0.81    6  ******                                                 
 -0.81/-0.76    4  ****                                                   
 -0.76/-0.71    7  #*******                                               
 -0.71/-0.66    2  **                                                     
 -0.66/-0.62    8  ********                                               
 -0.62/-0.57    5  *****                                                  
 -0.57/-0.52    8  ********                                               
 -0.52/-0.47    6  #******                                                
 -0.47/-0.43    9  *********                                              
 -0.43/-0.38   17  *****************                                      
 -0.38/-0.33   13  #*************                                         
 -0.33/-0.28   13  *************                                          
 -0.28/-0.24   12  ************                                           
 -0.24/-0.19   14  **************                                         
 -0.19/-0.14   17  *****************                                      
 -0.14/-0.09   18  #******************                                    
 -0.09/-0.05   20  ********************                                   
 -0.05/ 0.00   12  ************                                           
  0.00/ 0.05   34  **********************************                     
  0.05/ 0.09   28  ****************************                           
  0.09/ 0.14   19  *******************                                    
  0.14/ 0.19   12  ************                                           
  0.19/ 0.24   14  **************                                         
  0.24/ 0.28   10  **********                                             
  0.28/ 0.33   13  *************                                          
  0.33/ 0.38   15  ***************                                        
  0.38/ 0.43   17  *****************                                      
  0.43/ 0.47   16  ****************                                       
  0.47/ 0.52    9  *********                                              
  0.52/ 0.57   19  *******************                                    
  0.57/ 0.62   15  ***************                                        
  0.62/ 0.66   21  *********************                                  
  0.66/ 0.71   14  **************                                         
  0.71/ 0.76   14  **************                                         
  0.76/ 0.81   26  #**************************                            
  0.81/ 0.85   20  ********************                                   
  0.85/ 0.90    9  #*********                                             
  0.90/ 0.95    9  *********                                              
  0.95/ 1.00    4  ****                                                   
  1.00/ 1.04    8  ********                                               
  1.04/ 1.09    3  ***                                                    
  1.09/ 1.14    3  ***                                                    
  1.14/ 1.19    3  ***                                                    

                            HISTOGRAM FOR INDIVIDUALS WITH NEGATIVE WEIGHTS
                            MISSING CASES=     2
 -1.19/-1.14    0                                                         
 -1.14/-1.09    0                                                         
 -1.09/-1.04    0                                                         
 -1.04/-1.00    0                                                         
 -1.00/-0.95    0                                                         
 -0.95/-0.90    0                                                         
 -0.90/-0.85    0                                                         
 -0.85/-0.81    0                                                         
 -0.81/-0.76    0                                                         
 -0.76/-0.71    1  #*                                                     
 -0.71/-0.66    1  *                                                      
 -0.66/-0.62    1  *                                                      
 -0.62/-0.57    2  **                                                     
 -0.57/-0.52    0                                                         
 -0.52/-0.47    0  #                                                      
 -0.47/-0.43    1  *                                                      
 -0.43/-0.38    0                                                         
 -0.38/-0.33    1  #*                                                     
 -0.33/-0.28    2  **                                                     
 -0.28/-0.24    7  *******                                                
 -0.24/-0.19    2  **                                                     
 -0.19/-0.14    1  *                                                      
 -0.14/-0.09    7  #*******                                               
 -0.09/-0.05    5  *****                                                  
 -0.05/ 0.00    9  *********                                              
  0.00/ 0.05   14  **************                                         
  0.05/ 0.09    4  ****                                                   
  0.09/ 0.14    6  ******                                                 
  0.14/ 0.19    3  ***                                                    
  0.19/ 0.24    1  *                                                      
  0.24/ 0.28    0                                                         
  0.28/ 0.33    0                                                         
  0.33/ 0.38    1  *                                                      
  0.38/ 0.43    0                                                         
  0.43/ 0.47    0                                                         
  0.47/ 0.52    0                                                         
  0.52/ 0.57    1  *                                                      
  0.57/ 0.62    1  *                                                      
  0.62/ 0.66    0                                                         
  0.66/ 0.71    0                                                         
  0.71/ 0.76    0                                                         
  0.76/ 0.81    1  #*                                                     
  0.81/ 0.85    0                                                         
  0.85/ 0.90    0  #                                                      
  0.90/ 0.95    0                                                         
  0.95/ 1.00    0                                                         
  1.00/ 1.04    0                                                         
  1.04/ 1.09    0                                                         
  1.09/ 1.14    0                                                         
  1.14/ 1.19    0


Example of Coordinate Output file: LC1980X.PRN 

 LINE #  CASE # R POS   ALPHA    BETA    SCALED POS     RSQ
      1      1   6.0   -0.7579    0.1749    0.2915    0.3486    0.5904
      2      8   6.0   -1.8133    0.3510    0.2925    0.4537    0.6736
The first number is a simple integer counter.  The second number is
the ICPSR ID number for the respondent.  The third number is the respondent's
self placement on the 7-Point scale.  The next two numbers are the respondent's
linear mapping and the sixth number is the respondent's scaled position.  The
last two numbers are the Pearson r-square and simple Pearson r for the 
respondent.
      3      9   6.0   -1.4465    0.3774    0.8176    0.8807    0.9385
      4     10   4.0   -0.5711    0.1371   -0.0228    0.0535    0.2314
      5     11   5.0    0.5583   -0.1080    0.0180    0.0819   -0.2863
      6     13   7.0   -1.5281    0.3056    0.6112    0.6231    0.7894
      7     14   4.0   -1.5886    0.3813   -0.0635    0.8991    0.9482
      8     16   6.0   -1.1438    0.2640    0.4399    0.6778    0.8233
     10     19   5.0   -1.5090    0.3482    0.2322    0.6741    0.8211

etc.

    881   1606   4.0   -0.6253    0.1787    0.0893    0.1264    0.3556
    882   1607   7.0   -1.0925    0.3122    1.0925    0.8735    0.9346
    883   1608   6.0   -0.7471    0.2134    0.5336    0.7124    0.8440
    885   1610   4.0   -0.9489    0.2190   -0.0730    0.1466    0.3829
    887   1613   6.0   -1.5140    0.3949    0.8557    0.9647    0.9822


If you need help send me E-Mail at: KPoole@ucsd.edu