1: Two techniques, principal axes factor extraction and iterated principal axes factor extraction, are PCA methods and not EFA by default. Initial extraction of communalities using the squared multiple correlation must be specified using the PRIORS = SMC option in order for EFA extraction to occur. [return]

2: Note the following detail where an orthogonal rotation is used. Oblique rotations are slightly more complicated if doing the calculation by hand, as the factors are correlated. Communalities in this case are the sum of each variable’s pattern loading multiplied by the structure loading. Statistical software handles these complexities for us. [return]

3: Please note that alpha extraction and maximum likelihood extraction are weighted extraction methods. The unweighted initial estimates are identical but SAS presents only the weighted version of the initial estimates. [return]

4: Interested readers can get much more information on this and other technical details of extraction in Nunnally & Bernstein (1994), particularly Chapter 11. For our purposes, we aim to provide a more applied overview, and so will skip most of the technical details. [return]

5: Please note, there is one other extraction method, principal components analysis. There are also two additional extraction options to recognize and perform analyses on a set of scoring coefficients or a factor pattern matrix. These are excluded from this explanation because they are not specific EFA methods. [return]