Paper on linear growth curve modeling with
lmertree() published: Fokkema M, Zeileis A (2024).
“Subgroup Detection in Linear Growth Curve Models with Generalized
Linear Mixed Model (GLMM) Trees.” Behavior Research Methods,
56(7), 6759-6780. doi:10.3758/s13428-024-02389-1
Reduce precision in tests in order to avoid NOTEs in CRAN checks.
Added functions cv.lmertree() and
cv.glmertree(), implementing honest estimation of model
coefficients per Athey & Imbens (2016)
Fixed bug in coef() method
betamertree().
Additional arguments to lattice::dotplot can now be
passed to
plot.lmertree()/plot.glmertree().
Dedicated plotting function for partitioning growth curves has
been added, see which = "growth" in
?plot.lmertree and ?plot.glmertree.
Minor bug fixes.
Experimental function betamertree() added, for
partitioning mixed-effects beta regression trees.
Bug fix for missing data: Listwise deletion over all predictor, response, and splitting variables is now applied. Otherwise, global and local parts of (g)lmertree model could be estimated based on a different sample size or an error could occur.
Fixed bug: If dot . was used in formula
for specifying partitioning variables, tree fitting would pick up tree
structure from previous iteration. Fixed now.
Fixed bug: When type = "simple" in call to function
plot.lmertree() and plot.glmertree() is
specified, further arguments are now passed correctly.
Bug fix in predict() method: Erroneous allocation of
new observations to tree nodes could occur, which has been fixed
now.
New plotting method for (g)lmertrees. Arguments
which, type, and fitted now
support wider range of plots. E.g., fitted argument
provides different ways to compute fitted values in terminal panel
plots. E.g., type argument now supports the plotting of
fixed-effects coefficients with standard-error bars.
Two artificial example datasets added to illustate fitting of
constant fits (MHserviceDemo) and growth-curve models
(GrowthCurveDemo) in terminal nodes.
New sections added to vignette, illustrating how mixed-effects regression trees with constant fits and growth curve models in terminal nodes can be fitted.
Functions glmertree() and lmertree()
now take offset arguments.
Argument ranefstart of functions
glmertree() and lmertree() can now be set to
TRUE. As a result, the random effects will be estimated
before fitting the tree in the first iteration. This may yield better
results when random effects are expected to be substantial.
Functions glmertree() and lmertree()
now take cluster argument, an optional vector with cluster
IDs to be employed for clustered covariances in the parameter stability
tests.
Bugs fixed: Argument dfsplit is now passed correctly
to tree fitting functions, additional arguments are now passed correctly
to lmer() and glmer().
Arguments lmer.control in lmertree()
and glmer.control in glmertree() are now
actually passed to lmer() and glmer()
internally.
First CRAN release of the glmertree package for
fitting generalized linear mixed-effects model trees in R. For an
introduction to the underlying methods see
Fokkema, Smits, Zeileis, Hothorn, Kelderman (2015). Detecting Treatment-Subgroup Interactions in Clustered Data with Generalized Linear Mixed-Effects Model Trees. Working Paper 2015-10. Working Papers in Economics and Statistics, Research Platform Empirical and Experimental Economics, Universitaet Innsbruck. URL https://EconPapers.RePEc.org/RePEc:inn:wpaper:2015-10
The package is under development on R-Forge at https://R-Forge.R-project.org/projects/partykit/