Creates an Screeplot Including a Parallel Analysis (Horn), formatted according to APA 7th style. The original code was developed by John Sakaluk Check the original source: at his wordpress blog.
Arguments
- parallel
an parallel object returned by
psych::fa.parallel- fa
either "pc" or "fa" factor methods are allowed for the parallel analysis
- quant
default = .95 the quantile of the simulated values used to plot
- custom_optimal
default = NA, e.g., setting a marked dashed line to the location determined by fa.parallel. Given 0 hides the line, all other value > 0 set the dashed line to a custom location (e.g., to indicate a prefered number of factors determined by VSS or MAP)