Exploratory Factor Analysis - using PCF vs PF

[Victoria Vayer]

Hi Folx,

First time poster and novice Stata user here. I was hoping I could get some advice on when to use the default "pf" option of the factor command, and when to use the "pcf" option. I understand there are differences between PCA and EFA but I'm wondering why "pcf" is an option under factor analysis when Stata has a separate command for PCA. If I'm trying to do an EFA should I use the default "pf" option?

Thanks in advance! I've been looking this up for days but can't seem to find a consensus. And using the "help factor" command to look at the difference between "pf" and "pcf" didn't help me much. (Maybe it went over my head)

Torey

[William Lisowski]

I'm wondering why "pcf" is an option under factor analysis when Stata has a separate command for PCA

I commonly see "principal component analysis" used as shorthand for "factor analysis using principal component analysis for factor extraction", but the two are not the same. This confusion is enhanced by SPSS's apparent lack of a separate command for doing principal component analysis other than as the first step of a factor analysis. Wikipedia's discussions of principal component analysis and factor analysis help clarify the distinction. In particular, from the article on principal component analysis,

PCA is generally preferred for purposes of data reduction (i.e., translating variable space into optimal factor space) but not when the goal is to detect the latent construct or factors. ... Factor analysis is generally used when the research purpose is detecting data structure (i.e., latent constructs or factors) or causal modeling.

In the factor command, the first step is the extraction of the factors. Stata supports four techniques for doing so, and one of them is to start with the principal components.

With that said, there is much help to be found in the "Remarks and examples" section of the documentation for the factor command in the Stata Multivariate Statistics Reference Manual PDF included in your Stata installation and accessible through Stata's Help menu.