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.

Author
Dimitris Rizopoulos <d.rizopoulos@erasmusmc.nl>
Date of publication
2013-12-20 10:59:19
Maintainer
Dimitris Rizopoulos <d.rizopoulos@erasmusmc.nl>
License
GPL (>= 2)
Version
1.0-0
URLs

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