EXTRACTION Subcommand (FACTOR command)

EXTRACTION specifies the factor extraction technique.

  • Only one EXTRACTION subcommand is allowed. If multiple EXTRACTION subcommands are specified, only the last is performed.
  • If any ANALYSIS subcommand is explicitly specified, all EXTRACTION subcommands before the last ANALYSIS subcommand are ignored. If no EXTRACTION subcommand is specified after the last ANALYSIS subcommand, the default extraction is performed.
  • If EXTRACTION is not specified or is included without specifications, principal components extraction is used.
  • If you specify criteria for EXTRACTION, the CRITERIA subcommand must precede the EXTRACTION subcommand.
  • When you specify EXTRACTION, you should always explicitly specify the ROTATION subcommand. If ROTATION is not specified, the factors are not rotated.

PC. Principal components analysis 1. This is the default. PC can also be requested with keyword PA1 or DEFAULT.

PAF. Principal axis factoring. PAF can also be requested with keyword PA2.

ALPHA. Alpha factoring 2. Invalid if METHOD=COVARIANCE.

IMAGE. Image factoring 3.

ULS. Unweighted least squares 4. Invalid if METHOD=COVARIANCE.

GLS. Generalized least squares. Invalid if METHOD=COVARIANCE.

ML. Maximum likelihood 5. Invalid if METHOD=COVARIANCE.

Example

FACTOR VARIABLES=V1 TO V12
  /ANALYSIS=V1 TO V6
  /EXTRACTION=ULS
  /ROTATE=NOROTATE.
  • This example analyzes variables V1 through V6 with an unweighted least-squares extraction. No rotation is performed.
1 Harman, H. H. 1976. Modern Factor Analysis, 3rd ed. Chicago: University of Chicago Press.
2 Kaiser, H. F., and J. Caffry. 1965. Alpha factor analysis. Psychometrika, 30, 1-14.
3 Kaiser, H. F. 1963. Image analysis. In: Problems in Measuring Change, C. W. Harris, eds. Madison: University of Wisconsin Press.
4 Jöreskog, K. G. 1977. Factor analysis by least-square and maximum-likelihood method. In: Statistical Methods for Digital Computers, volume 3, K. Enslein, A. Ralston, and R. S. Wilf, eds. New York: John Wiley and Sons.
5 Jöreskog, K. G., and D. N. Lawley. 1968. New methods in maximum likelihood factor analysis. British Journal of Mathematical and Statistical Psychology, 21, 85-96.