# (exploratory) factor analysis with additional variable

This is sort of a repost of this question, but there weren't any answers so I will ask it again and I will try to make it clear what my problem is.

My eventual aim is to find out the relationship between one independent variable and many dependent variables. Because I have many of these dependent variables I decided to use an Exploratory Facor Analysis to first reduce the number of items to fewer latent variables. Also, all these dependent variable are questionaires investigating similar, but not the same thing. And then I wanted to check whether my independent variable can predict some of the latent variables yielded by the EFA.

Now, I wonder whether I can throw my independent variable into the EFA as well and see on which latent variable it has the highest loading on? Or is that entirely unusual to do? And would it mess up my latent variables?

• Hi Annamarie--welcome to the site. A quick clarification question: are you more interested in using your IV to predict the the "stuff" that is similar among the questionnaires as your DV, or are you more interested in using your IV to predict the "stuff" that is unique about the similar questionnaires as your DV? Commented Aug 1, 2016 at 17:48
• Hi jsakaluk, I am not sure whether I fully understand your question. My items in the questionnaires cover different cognitive skills. First I tried an orthogonal approach with 'varimax' and if I understand it right, then this means that the factors are more unique (sharing less variance). But since different cognitive capabilities are not independent from each other, I tried the factor analysis with and oblique rotation (factors more similar?). In the end, I wanted to see, if I can predict cogniton with my IV. Commented Aug 2, 2016 at 13:48
• Put another way, are you more interested in using your IV to predict--and therefore draw conclusions about--cognitive capability, in general (i.e. what these questionnaires would share in common with one another), or are you more interested in using your IV to predict--and therefore draw conclusions about--each of the idiosyncratic cognitive skills, individually? Commented Aug 2, 2016 at 20:12
• Hey jsakaluk, indeed I am more interested in specific cognitive skills. I assume that my IV will influence cognition in general, but I am trying to find out, which part of cognition is affected the most. Probably the cleanest thing to do is to extract the factors and then do the regression with the factor as DV. But I was wondering if I could also put the IV in the EFA and assess on which skills the IV has most influence judging by the loading of the IV. I am just not sure, whether that will entirely mess up the factors. Commented Aug 3, 2016 at 8:53