Exploratory factor analysis example

Example of exploratory factor analysis workflow based on the article by Mesquita and Lazzarini, 2008. Explains factor rotation, factor loadings, commonality, uniqueness, and Harman's single-factor test.
Slide set of video: osf.io/dgvpf

[@cracrul]

Hi teacher.
Please help me with the following:
1.- What is the difference between using the polychoric correlation matrix vs Pearson for an EFA? In social sciences, it is common to work with a Likert scale (1 to 5).
2.- What is your opinion of using the parallel method to explore the number of factors?
3.- Which method do you recommend or have the best performance: MINRES, Ml, PAF?
Thank you very much!

[@mronkko]

1) Polychoric assumes an underlying latent variable but only binary indicators are observed. In Pearson, we assume that the variables that we observe are of direct interest. See
Rhemtulla, M., Brosseau-Liard, P. É., & Savalei, V. (2012). When can categorical variables be treated as continuous? A comparison of robust continuous and categorical SEM estimation methods under suboptimal conditions. Psychological Methods, 17(3), 354-373. dx.doi.org/10.1037/a0029315
and the broader IRT literature.
2) I do not now what "parallel method" is so I do not have an opinion on it.
3) Depends on the context. ML is a good default, PAF a fall back, and MINRES is good for teaching but not for anything else.

[@cracrul]

@@mronkko Very clear, professor.
Thank you so much!