Analysis of Ordinal Variables Part 4: Multiple Groups
Karl G. Joreskog
February 5, 2002
Because of the mathematical content and length of this contribution to Karl's Corner, we are only making
it available as a PDF file. It can be printed using Adobe's Acrobat Reader (version 4 and higher).
The zip file ordinal4.zip contains both the PDF
file and examples (input files and datasets).
The contents of this column are briefly described below.
This Note considers the situation where data on the same ordinal variables have been collected in several
The objective is to compare different characteristics across groups. In particular, the procedure can be
used for testing factorial invariance and for estimating differences in factor means.
The analysis is carried out on the efficacy variables in the Political Action Survey administered in eight
countries (see Note 1). The procedure makes it possible to answer questions like these:
- Do the efficacy items measure the same latent variables in all countries?
- If so, are the factor loadings invariant over countries?
- Are the intercepts invariant over countries?