RMX - Rasch Models -- eXtensions
Extend Rasch and Item Response Theory (IRT) analyses by
providing tools for post-processing the output from five major
IRT packages (i.e., 'eRm', 'psychotools', 'ltm', 'mirt', and
'TAM'). The current version provides the plotPIccc() function,
which extracts from the return object of the originating
package all information required to draw an extended
Person-Item-Map (PIccc), showing any combination of * category
characteristic curves (CCCs), * threshold characteristic curves
(TCCs), * item characteristic curves (ICCs), * category
information functions (CIFs), * item information functions
(IIFs), * test information function (TIF), and the * standard
error curve (S.E.). for uni- and multidimensional models (as
far as supported by each package). It allows for selecting
dimensions, items, and categories to plot and offers numerous
options to adapt the output. The return object contains all
calculated values for further processing.
