[rwa-thebook] RMX 0.1-7

rainer.alexandrowicz@aau.at (Rainer W. Alexandrowicz) — Tue, 19 May 2026 08:41:18 GMT

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.

[rwa-thebook] GMX 0.9-2

rainer.alexandrowicz@aau.at (Rainer W. Alexandrowicz) — Tue, 10 Mar 2026 19:50:02 GMT

The function plotLRT() draws pairwise graphical model checks for the Rasch Model (RM; Rasch, 1960), the Partial Credit Model(PCM; Masters, 1982), and the Rating Scale Model (RSM; Andrich, 1978) using the output object of eRm::LRtest(). The function cLRT() provides a conditional Likelihood Ratio Test (Andersen, 1973), using the routines of 'psychotools'. Users may choose to plot the threshold parameters, the cumulative thresholds, the average thresholds per item, or the person parameters. Extended coloring options allow for automated item-wise or threshold-wise coloring. For multi-group splits, all pairwise group comparisons are drawn automatically. For more details see Andersen (1973) , Andrich (1978) , Masters (1982) and Rasch (1960, ISBN:9780598554512).

rwa-thebook.r-universe.dev

[rwa-thebook] RMX 0.1-7

[rwa-thebook] GMX 0.9-2