James Lo and Keith Poole
Updated 30 June 2011
Download basicspace:Aldrich-McKelvey and BasicSpace Analysis Software for R
Recovering a Basic Space in R (Vignette)
These Articles Detail the Methods Included in the Package:
- Aldrich, John H. 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.
- Poole, Keith T. 1998.
"How to Use the Black Box."
A Supplement to "Recovering a Basic Space From a Set of Issue Scales" that shows in
detail how to apply the various programs used in the article.
- Poole, Keith T. 2001. "The Relationship Between the Aldrich-McKelvey Scaling Solution
and the Individual Differences Problem." Manuscript, University of Houston.
Aldrich-McKelvey Examples
Additional Examples can be found on the Voteview Blog
BLACKBOX Examples
Additional Examples can be found on the Voteview Blog
basicspace_blackbox.r -- R program that
performs the basicspace scaling on the 1980 issue scales shown in
"Estimating a Basic Space From A Set of
Issue Scales," American Journal of Political Science, 42 (July 1998),
pp. 954-993. Program reads a text file with just the issue positions.
basicspace_blackbox_nes1980.r -- R program that
performs the basicspace scaling on the 1980 issue scales shown in
"Estimating a Basic Space From A Set of
Issue Scales," American Journal of Political Science, 42 (July 1998),
pp. 954-993. Program reads a STATA file containing the NES 1980 survey. To use the STATA 7 file just change
the read.dta() command
in the program.
basicspace_blackbox_nes1980_plots.r -- Same as
above but it also plots respondents across the first and second Basic Dimensions. This capability will be included in
the final package.
basicspace_blackbox_nes1980_bootstrap.r --
Same as
above but it also performs the bootstrap to obtain standard errors for the W and c coefficients for one to three dimensions.
The number of trials is set to 101 but any number can be used.
basicspace_blackbox_nes1992.r -- R program that
performs the basicspace scaling on 15 issue scales from the 1992 NES. This is a replication of the example shown in
the appendix to the 1998 article -- How to Use the Black Box. This program reads
the STATA file containing the entire 1992 NES survey. To use the STATA 7 file just change the read.dta() command
in the program.
BLACKBOX TRANSPOSE EXAMPLES
Additional Examples can be found on the Voteview Blog
basicspace_blackbox_transpose.r --
R program that performs the basicspace transpose scaling (a generalization of A-M to multiple
dimensions) on the 1980 Liberal-Conservative Seven Point Scale. This application is shown in
the appendix to the 1998 article -- How to Use the Black Box. The Transpose
Scaling Method can be used to test whether or not an Issue Scale is unidimensional.
LC1980V.DAT
-- 1980 L-C Data (See R Program for documentation)
basicspace_blackbox_transpose_L-C_2004_Stata.r --
R program that performs the basicspace transpose scaling on the 2004 Liberal-Conservative Seven Point Scale.
anes2004.DTA
-- 2004 NES 2004 (See R Program for documentation)
basicspace_blackbox_transpose_1968_Therms.r --
R program that performs a basicspace transpose scaling on the 12 Candidate Feeling Thermometers From the 1968 National
Election Study.
basicspace_big_blackbox_transpose_1968_Therms.r --
R program that performs a basicspace transpose scaling on the 12 Candidate Feeling Thermometers From the 1968 National
Election Study. This version removes the 1500 respondent restriction -- Use with caution! The program
reads this R program (courtesy of James Lo):
big_blackbox_transpose.R -- R code that creates the function
big_blackbox_transpose which is used in the R program above.
The R program produces a plot of the Candidate Configuration -- the Y (PSI) Matrix.
This matrix is normalized so that Y'Y=I.

The Respondents are the W matrix. Note that the scale is different from the Candidate Configuration because
this is, in effect, a singular value decomposition (see cited papers above) and not an unfolding analysis.
STATA FILES
The STATA files for the American National Election Studies were created using the data posted
on the NES website ANES Data Center Page.
NES2008_FIRST.DTA -- NES 2008 STATA 7 file
NES2008_FIRST_11.DTA -- NES 2008 STATA 11 file
NES2008_TRADITIONAL.DAT -- NES 2008 In traditional text format
NES2008_TRADITIONAL.CBK -- NES 2008 Codebook In traditional text format
NES2004_FIRST.DTA -- NES 2004 STATA 7 file
NES2004_FIRST_11.DTA -- NES 2004 STATA 11 file
NES2004_TRADITIONAL.DAT -- NES 2004 In traditional text format
NES2000_FIRST.DTA -- NES 2000 STATA 7 file
NES2000_FIRST_11.DTA -- NES 2000 STATA 11 file
NES2000_TRADITIONAL.DAT -- NES 2000 In traditional text format
NES1996_FIRST.DTA -- NES 1996 STATA 7 file
NES1996_FIRST_11.DTA -- NES 1996 STATA 11 file
NES1992_FIRST.DTA -- NES 1992 STATA 7 file
NES1992_FIRST_11.DTA -- NES 1992 STATA 11 file
NES1988_FIRST.DTA -- NES 1988 STATA 7 file
NES1988_FIRST_11.DTA -- NES 1988 STATA 11 file
NES1984_FIRST.DTA -- NES 1984 STATA 7 file
NES1984_FIRST_11.DTA -- NES 1984 STATA 11 file
NES1980_FIRST.DTA -- NES 1980 STATA 7 file
NES1980_FIRST_11.DTA -- NES 1980 STATA 11 file
NES1976_FIRST.DTA -- NES 1976 STATA 7 file
NES1976_FIRST_11.DTA -- NES 1976 STATA 11 file
NES1972_FIRST.DTA -- NES 1972 STATA 7 file
NES1972_FIRST_11.DTA -- NES 1972 STATA 11 file
NES1968_FIRST.DTA -- NES 1968 STATA 7 file
NES1968_FIRST_11.DTA -- NES 1968 STATA 11 file
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