COMPARE program information and links

The COMPARE program computes measures of factor congruence/similarity for two sets of factor loadings (typically the factor pattern). These include Tucker's (1951) coefficient of congruence, root-mean-square difference measures (see Harman, 1976), and the Cattell-Baggaley s-index (Cattell & Baggaley, 1960).  After the factors are compared users may optionally rotate them to maximum congruence (Korth & Tucker, 1976), then recompute the indices.

Tucker's congruence measure now seems to be the accepted standard for assessing factor similarity (Lorenzo-Seva & ten Berge, 2006).

Citation information:

    Fleming, J. S. (1991). COMPARE: An interactive program for computing measures of  similarity for factor loadings, with procrustes rotation options. [Computer software]. Available from:

Download information:

   Download file using ftp. It contains two zipped files: Compare.doc (a "how to" Word document), and the executable program, compare.exe.


    Cattell, R. B.,.& Baggaley, A. R. (1960). Thesalient variable similarity index for factor matching. British Journal of Statistical Psychology, 13, 33-46.

    Harman, H. H. (1976). Modern factor analysis (2nd. Ed.). Chicago: University of Chicago Press.

    Korth, B., & Tucker, L. R (1976). Procrustes matching by congruence coefficients. Psychometrika, 41, 531-535.

    Lorenzo-Seva, U., & ten Berge, J. M. F. (2006). Tucker's coefficient of congruence as a meaningful index of factor similarity. Methodology, 2, 57-64.

    Tucker, L. R (1951). A method for synthesis of factor analysis studies. Personnel Research Section Report No. 984. Washington, D.C.: Department of the Army.