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Estimation

Pairwise conditional estimation of the Rasch model family, with Godambe sandwich standard errors and Warm person measures.

rasch()
Fit and diagnose a Rasch model by pairwise conditional estimation
rasch_mfrm()
Fit a many-facet Rasch model
rasch_efrm()
Fit the extended frame of reference model
pcml()
Estimate Rasch thresholds by pairwise conditional maximum likelihood
pcml_pc()
Estimate Rasch thresholds via the Andrich principal-components reparameterisation
threshold_index()
Enumerate item-category thresholds
item_moments()
Category-score moments for a polytomous item

Test of fit and comparison

The fit-residual and chi-square apparatus, targeting and reliability, and model comparison.

fit_summary_table()
Test-of-fit summary as a table
targeting_table()
Targeting and reliability summary as a table
chisq_detail()
Class-interval detail for one item's chi-square test of fit
test_information()
Test information function
lr_test()
Likelihood-ratio test of the partial credit against the rating scale model
compare_fits()
Compare fitted Rasch models
guttman_table()
Guttman-ordered response matrix and reproducibility

Persons

person_wle()
Warm's weighted likelihood estimates by raw score
person_extrapolated()
Person measures with extrapolated extreme scores
score_table()
Raw score to measure conversion table

Invariance and DIF

Differential item functioning over any number of person factors, DIF magnitudes in logits, resolution by item splitting, and equating.

dif_anova()
Differential item functioning by residual analysis of variance
dif_contrasts()
Planned DIF contrasts derived from the factor structure
dif_size()
DIF magnitude in logits with pairwise comparisons
split_items()
Split items by a person factor to resolve DIF
resolve_dif()
Resolve differential item functioning by iterative item splitting
equate_tests()
Equate two test calibrations through their common items
tailored_analysis()
Tailored analysis for guessing

Independence and dimensionality

Residual principal components, the Smith t-test with magnitude estimation, Q3 local dependence, and the structural remedies.

residual_correlations()
Residual correlations for local dependence (Yen's Q3)
residual_pca()
Principal components of the residual correlations
dimensionality_test()
Residual-component test of unidimensionality
dimensionality_magnitude()
Magnitude of multidimensionality from a subtest analysis
dependence_magnitude()
Estimate the magnitude of response dependence between two items
spread_test()
Spread-parameter test for dependence within subtests
combine_items()
Combine items into subtests and re-analyse
rack_data() stack_data()
Reshape repeated measurements for racked or stacked analysis

Multiple choice and traditional statistics

distractor_analysis()
Distractor analysis for multiple-choice items
distractor_rescore()
Propose polytomous option scores from the distractor evidence
ctt_table()
Traditional (classical test theory) statistics

Paired comparisons

The Bradley-Terry-Luce model as the conditional form of the dichotomous Rasch model, with judge diagnostics, within-judge dependence, judge-group DIF, and the pair-structure analogues of the independence diagnostics (transitivity and the residual bimension decomposition).

btl()
Fit the Bradley-Terry-Luce model to paired comparisons
btl_dif()
DIF analysis for paired comparisons
btl_efrm()
Fit the extended frame of reference model for paired comparisons
btl_transitivity()
Transitivity of paired comparisons
btl_dimensionality()
Residual dimensionality of paired comparisons
btl_equate()
Equate two paired-comparison calibrations through their common objects
btl_information()
Information and targeting of a paired-comparison design
btl_next_pairs()
Recommend the next informative comparisons (adaptive step)
judge_surprise()
Unexpected judgements of one judge
judge_pair_surprise()
Unexpected judgements of one judge, pair by pair
plot_btl()
Plot Bradley-Terry-Luce object locations
plot_btl_categories()
Plot graded-comparison category curves
plot_btl_icc()
Plot an object characteristic curve
plot_btl_dependence()
Plot a within-judge dependence effect
plot_btl_transitivity()
Consistency plot for paired-comparison transitivity
plot_btl_scree()
Scree of paired-comparison residual bimensions
plot_btl_dim_map()
Residual map of the leading paired-comparison bimension
plot_btl_judge_map()
Unexpected-judgement map for one judge (pair level)
plot_btl_units()
Plot the frame units of a paired-comparison EFRM fit
plot_btl_equate()
Plot a paired-comparison equating comparison
plot_btl_targeting()
Targeting plot for a paired-comparison design

Plots

One plotting function per display, all base graphics.

plot_catfreq()
Plot category frequencies
plot_ccc()
Plot category probability curves
plot_distractors()
Plot multiple-choice option curves
plot_equate()
Plot a test-equating comparison
plot_facets()
Plot facet severities
plot_frames()
Plot frame units
plot_guttman()
Plot the Guttman scalogram
plot_icc()
Plot an item characteristic curve
plot_icc_frames()
Plot an item's characteristic curves across frames
plot_item_map()
Plot the item map (location against fit residual)
plot_kidmap()
Plot a kidmap
plot_pca()
Plot residual principal-component loadings
plot_pca_biplot()
Biplot of the first two residual components
plot_pcc()
Plot a person characteristic curve
plot_person_fit()
Plot person fit
plot_pimap()
Plot the person-item threshold distribution
plot_recovery()
Recovery scatter of planted against recovered parameters
plot_resid_cor()
Plot the residual-correlation heatmap
plot_resid_dist()
Plot the fit residual distribution
plot_scree()
Scree plot of the residual components with parallel analysis
plot_tcc()
Plot the test characteristic curve
plot_threshold_map()
Plot the threshold map
plot_threshold_prob()
Plot threshold probability curves
plot_tif()
Plot the test information function
plot_wright()
Plot a Wright map

Data simulation

Generate data from each model family with dial-in departures from it, so a known pathology can be planted and the matching diagnostic watched as it fires. The true parameters are attached to every result.

simulate_rasch()
Simulate person-by-item Rasch data with dial-in misfit
simulate_btl()
Simulate paired-comparison (BTL) data with dial-in misfit
simulate_mfrm()
Simulate many-facet (rated) data with dial-in misfit
simulate_efrm()
Simulate extended frame-of-reference data with differing units
simulate_btl_efrm()
Simulate paired-comparison EFRM data with differing frame units
sim_replicate()
Replicate a simulation for Monte Carlo studies
sim_recovery()
Parameter recovery of a fit against the simulation truth
plot_recovery()
Recovery scatter of planted against recovered parameters

Export and interface

save_outputs()
Save every output of a Rasch analysis to a folder
save_item_plots()
Save a plot for every item
save_person_plots()
Save a kidmap for every person
report_html()
Write a self-contained HTML report of a Rasch analysis
run_app()
Launch the rasch graphical interface