performance Files

New functions

• item_omega(), to calculate the McDonald's Omega reliability coefficient.

• item_totalcor() calculates the total correlation of an item with the sum of all other items in a scale. If corrected = TRUE, the total correlation is corrected for the number of items in the scale (which is equivalent to item_discrimination()).

• Column names of item_reliability() were changed to be in line with the easystats naming convention and to be consistent with the output of other related functions.

Changes

• check_itemscale() now work with factor analysis results, from parameters::factor_analysis().

• item_reliability() now includes the item-total correlation, and information about Cronbach's alpha and mean inter-item correlation in the printed output.

• cronbachs_alpha() now work with factor analysis results, from parameters::factor_analysis().

• Formatting of p-values in test_likelihoodratio() is now consistent with formatted p-values from other functions.

• Added following methods for psych::fa(), psych::principal(), item_omega(), psych::omega(), and parameters::factor_analysis(): check_normality(), check_residuals(), check_outliers(), and model_performance().

• item_alpha() was added as an alias for cronbachs_alpha().

• Further functions get a display(), print_md() and print_html() method.

Bug fixes

• Fixed issue in check_predictions() for binomial models with a response defined as proportion or matrix of successes and trials.

• print_md() for objects returned by check_itemscale() now include the footer with information about Cronbach's alpha and mean inter-item correlation.