Package: ltm 1.2-0

ltm: Latent Trait Models under IRT

Analysis of multivariate dichotomous and polytomous data using latent trait models under the Item Response Theory approach. It includes the Rasch, the Two-Parameter Logistic, the Birnbaum's Three-Parameter, the Graded Response, and the Generalized Partial Credit Models.

Authors:Dimitris Rizopoulos <[email protected]>

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ltm.pdf |ltm.html✨
ltm/json (API)
NEWS

# Install 'ltm' in R:
install.packages('ltm', repos = c('https://drizopoulos.r-universe.dev', 'https://cloud.r-project.org'))

Peer review:

Bug tracker:https://github.com/drizopoulos/ltm/issues

Datasets:
  • Abortion - Attitude Towards Abortion
  • Environment - Attitude to the Environment
  • LSAT - The Law School Admission Test (LSAT), Section VI
  • Mobility - Women's Mobility
  • Science - Attitude to Science and Technology
  • WIRS - Workplace Industrial Relation Survey Data
  • gh - Gauss-Hermite Quadrature Points

On CRAN:

67 exports 30 stars 6.56 score 9 dependencies 26 dependents 81 mentions 772 scripts 5.5k downloads

Last updated 3 years agofrom:3050c46f19. Checks:OK: 7. Indexed: yes.

TargetResultDate
Doc / VignettesOKAug 26 2024
R-4.5-winOKAug 26 2024
R-4.5-linuxOKAug 26 2024
R-4.4-winOKAug 26 2024
R-4.4-macOKAug 26 2024
R-4.3-winOKAug 26 2024
R-4.3-macOKAug 26 2024

Exports:anova.gpcmanova.grmanova.ltmanova.raschanova.tpmbiserial.corcoef.gpcmcoef.grmcoef.ltmcoef.raschcoef.tpmcronbach.alphadescriptfactor.scoresfactor.scores.gpcmfactor.scores.grmfactor.scores.ltmfactor.scores.raschfactor.scores.tpmfitted.gpcmfitted.grmfitted.ltmfitted.raschfitted.tpmGoF.gpcmGoF.raschgpcmgrminformationitem.fitltmmarginsmargins.grmmargins.ltmmargins.raschmargins.tpmmult.choiceperson.fitplot.descriptplot.fscoresplot.gpcmplot.grmplot.ltmplot.raschplot.tpmraschrcor.testresiduals.gpcmresiduals.grmresiduals.ltmresiduals.raschresiduals.tpmrmvlogisrmvordlogissummary.gpcmsummary.grmsummary.ltmsummary.raschsummary.tpmtestEquatingDatatpmunidimTestvcov.gpcmvcov.grmvcov.ltmvcov.raschvcov.tpm

Dependencies:admiscexpmlatticeMASSMatrixmsmmvtnormpolycorsurvival

Readme and manuals

Help Manual

Help pageTopics
Latent Trait Models for Item Response Theory Analysesltm-package
Attitude Towards AbortionAbortion
Anova method for fitted IRT modelsanova.gpcm anova.grm anova.ltm anova.rasch anova.tpm
Point-Biserial Correlationbiserial.cor
Extract Estimated Loadingscoef.gpcm coef.grm coef.ltm coef.rasch coef.tpm
Cronbach's alphacronbach.alpha
Descriptive Statisticsdescript
Attitude to the EnvironmentEnvironment
Factor Scores - Ability Estimatesfactor.scores factor.scores.gpcm factor.scores.grm factor.scores.ltm factor.scores.rasch factor.scores.tpm
Fitted Values for IRT modelfitted.gpcm fitted.grm fitted.ltm fitted.rasch fitted.tpm
Gauss-Hermite Quadrature Pointsgh
Goodness of Fit for Rasch ModelsGoF.gpcm GoF.rasch
Generalized Partial Credit Model - Polytomous IRTgpcm
Graded Response Model - Polytomous IRTgrm
Area under the Test or Item Information Curvesinformation
Item-Fit Statistics and P-valuesitem.fit
The Law School Admission Test (LSAT), Section VILSAT
Latent Trait Model - Latent Variable Model for Binary Dataltm
Fit of the model on the marginsmargins margins.gpcm margins.grm margins.ltm margins.rasch margins.tpm
Women's MobilityMobility
Multiple Choice Items to Binary Responsesmult.choice
Person-Fit Statistics and P-valuesperson.fit
Descriptive Statistics Plot methodplot.descript
Factor Scores - Ability Estimates Plot methodplot.fscores
Plot method for fitted IRT modelsplot.gpcm plot.grm plot.ltm plot.rasch plot.tpm
Rasch Modelrasch
Pairwise Associations between Items using a Correlation Coefficientrcor.test
Residuals for IRT modelsresiduals.gpcm residuals.grm residuals.ltm residuals.rasch residuals.tpm
Generate Random Responses Patterns under Dichotomous and Polytomous IRT modelsrmvlogis rmvordlogis
Attitude to Science and TechnologyScience
Summary method for fitted IRT modelssummary.gpcm summary.grm summary.ltm summary.rasch summary.tpm
Prepares Data for Test EquatingtestEquatingData
Birnbaum's Three Parameter Modeltpm
Unidimensionality Check using Modified Parallel AnalysisunidimTest
vcov method for fitted IRT modelsvcov.gpcm vcov.grm vcov.ltm vcov.rasch vcov.tpm
Workplace Industrial Relation Survey DataWIRS