[R-pkgs] eRm: new version 0.9-6
Patrick Mair
patrick.mair at wu-wien.ac.at
Tue Jan 29 00:32:02 CET 2008
Dear useRs,
new and updated features in eRm 0.9-6 for extended Rasch modeling:
- infit and outfit mean-square statistics added to functions personfit()
and itemfit().
- new method: plotPImap() plots a person-item map (cf. Bond & Fox,
2007), i.e., a map
of locations of item (and threshold) parameters, and the distribution of
person parameters.
- new options in plotGOF():
'conf': draws confidence ellipses for item parameters, optionally single
items can be chosen interactively.
'ctrline': draws confidence bands along the diagonal line based on the
se's of the item parameters (cf. Wright &
Stone, 1999) .
plotGOF() now displays difficulty parameters (see below).
- unification of output for item parameter estimates: all plotting
functions and the function thresholds() display
item difficulty parameters. all numeric output (i.e. from model objects)
gives item easiness parameters.
- new and enhanced options in plotICC():
'empirical': empirical ICCs can now be smoothed using various smoothers
(such as Tukey, loess, or kernel).
'ask': interactive turning over of plots can be switched off (only
useful if automated figure export is in effect,
e.g., when using Sweave).
- simulation module for 0-1 response matrices: sim.rasch() for Rasch
homogeneous data,
sim.2pl() for 2-PL data, sim.xdim() for unidimensionality violation, and
sim.locdep() for locally dependent item responses.
- package vignette "eRmvig" added.
Best,
Patrick
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