- Nov 4, 2011
- Reaction score
Great thread guys. I just came across it. The type of topics discussed on SF never stop surprising me.
In response to the above, how do you differentiate between EFA and PCA? I hear people reference PCA as something different from Factor Analysis quite a bit; my understanding is that it's incorrect to do so, but I'm curious to see what you think.
My understanding is that Factor Analysis (whether Exploratory or Confirmatory) is the general technique. Component Analysis (also PCA) and Common Factor Analysis are two methods of extracting factors for Factor Analysis, not separate techniques.
Let's compare that to Multiple Regression analysis. MR is the analytical technique. Stepwise Estimation and Forward Addition/Backwards Elimination are model estimation methods (similar to PCA's role in Factor Analysis). No one refers to Stepwise Estimation as its own technique; it's one option that you can use to create a MR model, but people (erroneously) refer to PCA as a separate technique from Factor Analysis, rather than one possible extraction method that can be used for Factor Analysis.
Exploratory and Confirmatory Factor Analysis are uses of Factor Analysis for certain ends. PCA is an extraction method for Factor Analysis, not a separate technique "geared towards a similar 'type' of problem."
When I specified "type" of question, I was merely referencing that FA and PCA were options for a given type of question. For example, to find the indicators of job satisfaction from survey responses. I always considered FA to be an extension of PCA, but that the two were separate techniques. Both FA and PCA use different estimation procedures to identify the structure underlying a dataset. Given that I never use FA or PCA and have a limited working knowledge of both, I'm going to take the easy route and suggest that you have a look at the following link.
In regards to your comparison to MR...MR is the analytical technique and least squares, partial least squares, maximum likelihood estimation, etc are the estimation techniques. I don't think of stepwise regression as an estimation technique but a variable reduction technique. Stepwise can be implemented using backwards or forwards selection, but it's not directly related to the MR estimation process...once again, stepwise is something that I don't use, so don't hold me to it.