r-epmfd

Analysis of items and persons in data. To identify and remove person misfit in polytomous item-response data using either 'mokken' or a graded response model (GRM, via 'mirt'). Provides automatic thresholds, visual diagnostics (2D/3D), and export utilities. Methods build on Mokken scaling as in Mokken (1971, ISBN:9789027968821) and on the graded response model of Samejima (1969) <doi:10.1007/BF03372160>.