Recursive Partitioning for Graded Response Models
Overview
Provides methods for recursive partitioning based on the 'Graded Response Model' ('GRM'), extending the 'MOB' algorithm from the 'partykit' package. The package allows for fitting 'GRM' trees that partition the population into homogeneous subgroups based on item response patterns and covariates. Includes specialized plotting functions for visualizing 'GRM' trees with different terminal node displays (threshold regions, parameter profiles, and factor score distributions). The package also implements the Longitudinal GRMTree for detecting response shift in PROMs measured at two time points, embedding a constrained two-factor longitudinal GRM within recursive partitioning, with post-hoc characterization of recalibration and reprioritization. Random-forest ensembles (`grmforest()`) with permutation variable importance are available for both the cross-sectional and longitudinal trees. For more details on the methods, see Samejima (1969) doi:10.1002/J.2333-8504.1968.TB00153.X, Komboz et al. (2018) doi:10.1177/0013164416664394 and Arimoro et al. (2025) doi:10.1007/s11136-025-04018-6.
New features
grmforest()gainstree_funandtree_argsarguments so one forest engine serves both trees. The default (tree_fun = grmtree) grows a cross-sectional GRM forest exactly as before;tree_fun = longitudinal_grmtreewithtree_args = list(n_items = ...)grows a longitudinal GRM forest for response-shift detection.varimp()detects the tree type and scores out-of-bag respondents with the appropriate marginal likelihood, the two-occasion correlated-factor likelihood for longitudinal forests, so the samevarimp()call ranks covariates for either forest.longitudinal_grmtree()now freely estimates the follow-up latent variance (previously fixed to 1), so the two-factor model captures change in trait dispersion across occasions as well as in the mean. The variance remains a structural parameter held out of the split test.
From NEWS.md in the release
Install
Health
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Documentation
- Help pages
- 34 (4 internal)
- Examples that run
- 74%20 run in a plain check (16 of them under a condition) · 7 only when donttest examples are enabled (R CMD check --as-cran)
- Exported functions with examples
- 100%
- Documented parameters
- 100%
- Return-value docs
- 100%
- Help pages citing references
- 12%
Downloads
Repository
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Dependencies
Installing grmtree adds 81 packages (39 with compiled code, 45 MB of source tarballs). Heaviest: ggplot2 6.0 MB, SimDesign 2.4 MB, partykit 2.1 MB.
Code & Tests
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- 0.3.0Latest
- 0.2.22026-08-23 · diff ↗
- RR 4.6.0 released · 2026-04-24
- 0.2.02026-01-14 · diff ↗ ·
added 10 exports
discrpar_longitudinal_grmtree, fscores_longitudinal_grmtree, itempar_longitudinal_grmtree, latentpar_longitudinal_grmtree, longitudinal_grmtree, plot_rs_heatmap, plot_rs_tree, prepare_longitudinal_data, rs_characterize, threshpar_longitudinal_grmtree - 0.1.02026-01-14
- RR 4.5.0 released · 2025-04-11
Package metadata
- First published
- 2026-01-14
- Total releases
- 4 / 1 yrs
- License
- GPL-3 OSI
- Minimum R
- ≥ 4.1.0
- Bundled data
- 43 KB / 2 files
- Download size
- 334 KB
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