Hello,

This thread has been super informative. I'm also working with dichotomous variables (yes/no) that belong to a 15-item questionnaire. I'm in the process of doing an exploratory factor analysis using Principle Axis Factoring. I was able to calculate the tetrachoric correlation and run my code for EFA after that. However, I get a message on the output that says "Beware: solution is a Heywood case." I was wondering if someone could provide me with some guidance as to why I get this message?

Below is the code I use:

tetrachoric Bar1 Bar2 Bar3 Bar4 Bar5 Bar6 Bar7 Bar8 Bar9 Bar10 Bar11 Bar12 Bar13 Bar14 Bar15, posdef
matrix r = r(Rho)
matrix symeigen e v = r
matrix list v
factormat r, ipf n(194)

Additionally, in trying to determine how many factors I should run, I ran parallel analysis and using the following command:

fapara, factormat reps(10)

However, I do not seem to get a good solution as to how many factors I should run. Below is the graph I get. Does anyone know why I might be getting this output? Do you know of any resources I could use to help me determine how many factors I should run when my data are dichotomous? Any guidance will be much appreciated. Thank you!

Array