# What should I do to perform a confirmatory factor analysis using SPSS?

I'm trying to perform a confirmatory factor analysis using SPSS 19. I have a 240-item test, and, according to the initial model and other authors, I must obtain 24 factors. But, when I perform the factor analysis, I obtain 58 factors. What should I do to extract only 24 factors?

## Popular Answers

Rakesh Pandey· Banaras Hindu UniversityIf one does an EFA and obtains same number of factors then there is a need to assess the factor structure congruence. And if the index of factor structure congruence is high then one may conclude that the earlier reported factor structure may be generalized across different sample (population). This procedure may be termed as cross-validation of the factor structure and such procedure of factor analysis may be classified at best as inferential exploratory factor analysis and not the confirmatory factor analysis.

Confirmatory factor analysis is is a hypothesis testing approach to factor analysis where one defines the factor structure apriori and using the structural equation modeling approach how far the data fits with this predefined factor structure. If this is your objective then as suggested by others you will have to use special software like AMOS, LISREL, EQS etc.

However, if your objective is to do a cross validation of earlier reported factor structure then EFA is advised. Use any one method of EFA (preferably the one used in earlier research) and then use some tests to determine the number of factors to retain for subsequent rotation. It would be better if one adopts several criteria to decide the number of factors such as scree plot, parallel analysis, Velicer's MAP. C-Hull method etc.

If you get same number of factors as obtained in previous research even then you can not say that you have arrived at a similar factor structure unless you demonstrate that all the factors have pattern of factor loadings similar to the earlier one. This can be done by computing factor structure congruence that has been nicely described in the Book on factor analysis by Gorsuch.

Like many others, however, I also doubt that the 24 factors may not represent first order factor related to one second order latent construct. Rather, they may be related to several second order factors. And if this is the case then you will have to follow an entirely different approach to conduct the factor analysis.

Hope this helps.

Diogenes Bido· Universidade Presbiteriana MackenzieSPSS just run exploratory factor analysis (with principal components or common factor extraction).

AMOS is the package of SPSS that run confirmatory factor analysis, similar to LISREL, EQS and others.

If you do not have expertise with AMOS, LISREL…, one idea is:

- run one exploratory factor analysis for each original dimension (extracting just one factor)

- assess the convergent validity (factor loading, communality and variance extracted)

- assess the reliability (Cronbach’s alpha or composite reliability).

- you also could save the factor scores for each dimension and compute the correlation between them, to assess the discriminant validity.

Best regards,

Bido