Make sure that mob() from partykit (rather than party) is called by all tree functions.
Improved version of node_profileplot(..., what = ...) which now allows to visualize not only itempar() but also coef(), threshpar and so on by setting what = "item" or "coef" or "threshold" etc.
In previous versions the gpcmtree(..., minsize = ...) argument was ignored. Now it is passed on correctly to mob_control().
New functions npltree() and gpcmtree() with corresponding visualization functions for model-based recursive partitioning of parametric logistic IRT models (2PL, 3PL, 3PLu, 4PL, Rasch/1PL) and the generalized partial credit model, respectively. The output of these functions might still change slightly in future versions.
Make sure that the “raschtree” vignette can also be compiled even when the stablelearner package is not available.
stablelearner package (>= 0.1-3).IGNORE_RDIFF flags in some examples in order to avoid showing diffs due to small numeric deviations in some checks (especially on CRAN).The method behind mpttree() has now been published by Behavior Research Methods, see doi:10.3758/s13428-017-0937-z.
The predict() method for bttree objects works again correctly for type = "parameter" (previously called type = "worth") and type = "rank". Thanks to Heather Turner for pointing out the problem.
node_btplot() used to fail for worth = FALSE or ref = <character> but works now correctly again. Thanks to Heather Turner for pointing out the problem. Also ref = <character> now either matches to <object>$labels or (if not available) to colnames(<coefficients>) to facilitate usage with the PlackettLuce package.
node_regionplot() now also works correctly on devices with a default white (rather than transparent) background such as png() or jpeg().
node_* panel functions gained bg = "white" argument to enable different background filling color.
The recently added mpttree() function is now accompanied by a working paper, see citation("psychotree") or ?mpttree for details.
Properly imported grDevices in NAMESPACE.
Basil Abou El-Komboz changed his name to Basil Komboz.
mpttree() and visualization function for model-based recursive partitioning of multinomial processing tree (MPT) models. These functions are somewhat experimental, and their user interface might change in future releases.Internals of package psychotree completely reorganized to employ the recent additions and changes in psychotools (>= 0.3-0) and to use the new partykit (>= 0.2-0) implementation of the mob() function (rather than the old party implementation).
The handling of argument ref when producing a region/effect plot was changed. Whereas in the previous implementation, the restriction specified in this argument was applied to the cumulative absolute item threshold parameters, it now is applied to the absolute item threshold parameters.
New panel-generating visualization functions node_profileplot() and node_regionplot() have been added which replace the old functions node_raschplot() and node_effects().
pctree() and rstree(), respectively. These require package psychotools >= 0.2-0 which provides the corresponding basic model fitting tools.DESCRIPTION.Adjusted vignette “raschtree” according to the slightly different results due to the new approximation formulae for p values in the supLM test used in party::mob() (>= 1.0.3).
Improved the package’s tests by adding reference output for the examples and vignette for comparison checks.
Moved all base functionality to the new psychotools package in order to provide common infrastructure for both psychotree and psychomix as well as other packages. This affects the paircomp class and associated methods as well as the model fitters btReg.fit() and RaschModel.fit() and associated methods.
The data sets Firstnames, GermanParties2009, and Soundquality have also been moved to psychotools.
Enhanced raschtree() functionality, introduced in detail in the new vignette("raschtree", package = "psychotree").
Added subsample from SPIEGEL Studentenpisa (SPISA) quiz for students from Bavaria that answered the same set of questions.
Added artificial data set DIFSim exhibiting differential item functioning, employed for illustrating Rasch trees.
Added raschtree() function, based on simple RaschModel() (for binary 0/1 items).
Some bug fixes (subsets with missing drop = FALSE) for paircomp() and bttree() with only two objects
First CRAN release of the package accompanying the forthcoming paper Accounting for Individual Differences in Bradley-Terry Models by Means of Recursive Partitioning by Strobl, Wickelmaier, and Zeileis, accepted for publication in Journal of Educational and Behavioral Statistics.
Compared to earlier package versions available from R-Forge, this package does not depend on data/code from the prefmod2 package. All required functionality (basic Bradley-Terry regression, paircomp class, data sets) are now contained in the psychotree package.