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.

AuthorDimitris Rizopoulos <d.rizopoulos@erasmusmc.nl>
Date of publication2013-12-20 10:59:19
MaintainerDimitris Rizopoulos <d.rizopoulos@erasmusmc.nl>
LicenseGPL (>= 2)
Version1.0-0
http://rwiki.sciviews.org/doku.php?id=packages:cran:ltm

View on CRAN

Man pages

Abortion: Attitude Towards Abortion

anova: Anova method for fitted IRT models

biserial.cor: Point-Biserial Correlation

coef: Extract Estimated Loadings

cronbach.alpha: Cronbach's alpha

descript: Descriptive Statistics

Environment: Attitude to the Environment

factor.scores: Factor Scores - Ability Estimates

fitted: Fitted Values for IRT model

gh: Gauss-Hermite Quadrature Points

GoF: Goodness of Fit for Rasch Models

gpcm: Generalized Partial Credit Model - Polytomous IRT

grm: Graded Response Model - Polytomous IRT

information: Area under the Test or Item Information Curves

item.fit: Item-Fit Statistics and P-values

LSAT: The Law School Admission Test (LSAT), Section VI

ltm: Latent Trait Model - Latent Variable Model for Binary Data

ltm-package: Latent Trait Models for Item Response Theory Analyses

margins: Fit of the model on the margins

Mobility: Women's Mobility

mult.choice: Multiple Choice Items to Binary Responses

person.fit: Person-Fit Statistics and P-values

plot: Plot method for fitted IRT models

plot.descript: Descriptive Statistics Plot method

plot.fscores: Factor Scores - Ability Estimates Plot method

rasch: Rasch Model

rcor.test: Pairwise Associations between Items using a Correlation...

residuals: Residuals for IRT models

rmvlogis: Generate Random Responses Patterns under Dichotomous and...

Science: Attitude to Science and Technology

summary: Summary method for fitted IRT models

testEquatingData: Prepares Data for Test Equating

tpm: Birnbaum's Three Parameter Model

unidimTest: Unidimensionality Check using Modified Parallel Analysis

vcov: vcov method for fitted IRT models

WIRS: Workplace Industrial Relation Survey Data

Files in this package

ltm
ltm/inst
ltm/inst/CITATION
ltm/inst/NEWS
ltm/NAMESPACE
ltm/demo
ltm/demo/ltm.R
ltm/demo/rasch.R
ltm/demo/00Index
ltm/data
ltm/data/Abortion.rda
ltm/data/gh.rda
ltm/data/WIRS.rda
ltm/data/LSAT.rda
ltm/data/Science.rda
ltm/data/Mobility.rda
ltm/data/Environment.rda
ltm/R
ltm/R/vcov.rasch.R ltm/R/print.summ.ltm.R ltm/R/iprobs.R ltm/R/start.val.rasch.R ltm/R/scoregpcmSNW.R ltm/R/coef.ltm.R ltm/R/residuals.rasch.R ltm/R/jacobian.R ltm/R/residuals.gpcm.R ltm/R/vcov.gpcm.R ltm/R/item.fit.R ltm/R/observedFreqs.R ltm/R/fscores.t.R ltm/R/print.unidimTest.R ltm/R/vcov.ltm.R ltm/R/logLiktpm.R ltm/R/rcor.test.R ltm/R/fscores.r.R ltm/R/probs.R ltm/R/fscores.g.R ltm/R/summary.grm.R ltm/R/descript.R ltm/R/loglikltm.R ltm/R/summary.gpcm.R ltm/R/summary.rasch.R ltm/R/print.information.R ltm/R/GoF.gpcm.R ltm/R/print.tpm.R ltm/R/summary.ltm.R ltm/R/ltm.R ltm/R/plot.ltm.R ltm/R/factor.scores.tpm.R ltm/R/cronbach.alpha.R ltm/R/tpm.R ltm/R/print.summ.grm.R ltm/R/testEquatingData.R ltm/R/infoGPCM.R ltm/R/grm.R ltm/R/simulate.grm.R ltm/R/print.margins.grm.R ltm/R/logLik.grm.R ltm/R/chisq.irt.R ltm/R/anova.ltm.R ltm/R/cumprobs.R ltm/R/vcov.grm.R ltm/R/IRT.parm.ltm.R ltm/R/print.aov.ltm.R ltm/R/coef.grm.R ltm/R/print.gpcm.R ltm/R/margins.grm.R ltm/R/GHpoints.R ltm/R/biserial.cor.R ltm/R/ltm.fit.R ltm/R/print.aov.gpcm.R ltm/R/print.GoF.rasch.R ltm/R/infoprobs.R ltm/R/coef.tpm.R ltm/R/print.fscores.R ltm/R/factor.scores.grm.R ltm/R/matArrays.R ltm/R/print.rasch.R ltm/R/matches.R ltm/R/rmvlogis.R ltm/R/plot.gpcm.R ltm/R/rmvordlogis.R ltm/R/start.val.ltm.R ltm/R/EM.R ltm/R/anova.gpcm.R ltm/R/plot.fscores.R ltm/R/scoregpcm.R ltm/R/plot.grm.R ltm/R/crf.GPCM.R ltm/R/IRT.parm.tpm.R ltm/R/logLik.ltm.R ltm/R/betas.grm.R ltm/R/anova.tpm.R ltm/R/globals.R ltm/R/matMeans.R ltm/R/betas.ltm.R ltm/R/rasch.R ltm/R/GoF.rasch.R ltm/R/print.persFit.R ltm/R/scoretpm.R ltm/R/gpcm.R ltm/R/print.summ.rasch.R ltm/R/scoreltm.R ltm/R/anova.rasch.R ltm/R/coef.rasch.R ltm/R/fitted.grm.R ltm/R/print.grm.R ltm/R/residuals.grm.R ltm/R/start.val.gpcm.R ltm/R/summary.tpm.R ltm/R/plot.rasch.R ltm/R/fitted.rasch.R ltm/R/print.itemFit.R ltm/R/factor.scores.rasch.R ltm/R/print.summ.tpm.R ltm/R/plot.tpm.R ltm/R/crf.GPCM2.R ltm/R/print.aov.tpm.R ltm/R/fd.vec.R ltm/R/logLik.tpm.R ltm/R/plot.aov.gpcm.R ltm/R/simulate.gpcm.R ltm/R/betas.rasch2.R ltm/R/IRT.parm.grm.R ltm/R/loglikgrm.R ltm/R/gauher.R ltm/R/thetas.tpm.R ltm/R/person.fit.R ltm/R/factor.scores.gpcm.R ltm/R/fitted.gpcm.R ltm/R/fitted.tpm.R ltm/R/margins.ltm.R ltm/R/plot.descript.R ltm/R/fscores.gp.R ltm/R/print.rcor.test.R ltm/R/vcov.tpm.R ltm/R/margins.rasch.R ltm/R/print.aov.grm.R ltm/R/print.cronbachAlpha.R ltm/R/cd.tpm.R ltm/R/margins.tpm.R ltm/R/plot.unidimTest.R ltm/R/print.aov.rasch.R ltm/R/logLik.rasch.R ltm/R/margins.gpcm.R ltm/R/loglikgpcm.R ltm/R/anova.grm.R ltm/R/print.margins.gpcm.R ltm/R/cprobs.R ltm/R/print.GoF.gpcm.R ltm/R/fitted.ltm.R ltm/R/print.descript.R ltm/R/linpred.GPCM.R ltm/R/mult.choice.R ltm/R/IRT.parm.R ltm/R/matSums.R ltm/R/betas.gpcm.R ltm/R/cd.vec.R ltm/R/start.val.tpm.R ltm/R/start.val.grm.R ltm/R/print.summ.gpcm.R ltm/R/fscores.l.R ltm/R/margins.R ltm/R/scoregrm.R ltm/R/betas.rasch.R ltm/R/print.margins.ltm.R ltm/R/residuals.ltm.R ltm/R/print.ltm.R ltm/R/factor.scores.ltm.R ltm/R/logLik.gpcm.R ltm/R/factor.scores.R ltm/R/unidimTest.R ltm/R/residuals.tpm.R ltm/R/information.R ltm/R/coef.gpcm.R ltm/R/IRT.parm.rasch.R
ltm/MD5
ltm/DESCRIPTION
ltm/man
ltm/man/rasch.Rd ltm/man/gpcm.Rd ltm/man/biserial.cor.Rd ltm/man/anova.Rd ltm/man/rmvlogis.Rd ltm/man/person.fit.Rd ltm/man/WIRS.Rd ltm/man/information.Rd ltm/man/residuals.Rd ltm/man/unidimTest.Rd ltm/man/rcor.test.Rd ltm/man/Environment.Rd ltm/man/tpm.Rd ltm/man/grm.Rd ltm/man/item.fit.Rd ltm/man/cronbach.alpha.Rd ltm/man/ltm-package.Rd ltm/man/LSAT.Rd ltm/man/mult.choice.Rd ltm/man/Science.Rd ltm/man/gh.Rd ltm/man/testEquatingData.Rd ltm/man/vcov.Rd ltm/man/plot.descript.Rd ltm/man/Abortion.Rd ltm/man/factor.scores.Rd ltm/man/fitted.Rd ltm/man/ltm.Rd ltm/man/Mobility.Rd ltm/man/descript.Rd ltm/man/margins.Rd ltm/man/plot.Rd ltm/man/GoF.Rd ltm/man/plot.fscores.Rd ltm/man/coef.Rd ltm/man/summary.Rd

Questions? Problems? Suggestions? or email at ian@mutexlabs.com.

All documentation is copyright its authors; we didn't write any of that.