topic Re: Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations in Statistical Procedures

Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations

Barney1998 — Wed, 17 Apr 2024 04:34:41 GMT

Good morning everyone,
I need to analyze a questionnaire, essentially revisiting a study after some years.

My issue is that all variables are on a Likert scale. The categories from which I need to draw conclusions have been predefined. By that, I mean I've been told that certain questions correspond to a person's value, others to their knowledge, etc. The purpose of the research is to examine how subpopulations I have—such as men/women, smokers/non-smokers—differ.

Initially, I thought of conducting an explanatory factor analysis to get scores for these categories, but I couldn't get the desired categories the way I wanted. So, I thought of doing the following: Is it correct to conduct PCA separately for both categories to obtain the desired scores and proceed with the analysis?

Thank you very much for your time.

Re: Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations

Ksharp — Wed, 17 Apr 2024 05:31:32 GMT

Check PROC PRINQUAL and its examples in DOC .

Re: Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations

Ksharp — Wed, 17 Apr 2024 05:42:47 GMT

https://blogs.sas.com/content/iml/2014/11/07/distribution-of-blood-types.html

Re: Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations

Barney1998 — Wed, 17 Apr 2024 07:25:06 GMT

Thanks for answering!
Definitely, this article does not solve my problem. The question was if can procced via PCA as I told above.

Burney

Re: Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations

Ksharp — Wed, 17 Apr 2024 09:25:18 GMT

Answer is Yes.

Did you check PROC PRINQUAL and its examples ?

Re: Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations

Ksharp — Wed, 17 Apr 2024 09:32:32 GMT

Another way is using PROC CORRESP,but it is more suited to non-Likert scale.
Check its example .

Re: Questionnaire Analysis with Likert Scale: Using PCA to Assess Differences in Subpopulations

PaigeMiller — Wed, 17 Apr 2024 12:02:08 GMT

So, I thought of doing the following: Is it correct to conduct PCA separately for both categories to obtain the desired scores and proceed with the analysis?

First, I agree with the advice from @Ksharp

If I was to do PCA (or PRINQUAL or CORRESP) separately for both categories to see how the categories differed, I would want to look at the loadings, not the scores, to determine differences between the groups.

Another possibility (and one I recommend here) is to fit one PCA (or PRINQUAL or CORRESP) model to the entire data, then plot the scores (not the loadings) and see if the groups overlap or are separated. To determine what variables are associated with the "separation", you can then use Contribution Plots (for example, as in PROC MVPDIAGNOSE), see Miller, P., Swanson, R. E., and Heckler, C. H. E. (1998). “Contribution Plots: A Missing Link in Multivariate Quality Control.” Applied Mathematics and Computer Science 8:775–792. By the way, that first author is me.