R: Latent Trait Models under IRT

# Latent Trait Models under IRT

## Documentation for package ‘ltm’ version 1.2-0

- DESCRIPTION file
- Code demos. Use demo() to run them.
- Package NEWS

## Help Pages

ltm-package | Latent Trait Models for Item Response Theory Analyses
Abortion | Attitude Towards Abortion
anova.gpcm | Anova method for fitted IRT models
anova.grm | Anova method for fitted IRT models
anova.ltm | Anova method for fitted IRT models
anova.rasch | Anova method for fitted IRT models
anova.tpm | Anova method for fitted IRT models
biserial.cor | Point-Biserial Correlation
coef.gpcm | Extract Estimated Loadings
coef.grm | Extract Estimated Loadings
coef.ltm | Extract Estimated Loadings
coef.rasch | Extract Estimated Loadings
coef.tpm | Extract Estimated Loadings
cronbach.alpha | Cronbach's alpha
descript | Descriptive Statistics
Environment | Attitude to the Environment
factor.scores | Factor Scores - Ability Estimates
factor.scores.gpcm | Factor Scores - Ability Estimates
factor.scores.grm | Factor Scores - Ability Estimates
factor.scores.ltm | Factor Scores - Ability Estimates
factor.scores.rasch | Factor Scores - Ability Estimates
factor.scores.tpm | Factor Scores - Ability Estimates
fitted.gpcm | Fitted Values for IRT model
fitted.grm | Fitted Values for IRT model
fitted.ltm | Fitted Values for IRT model
fitted.rasch | Fitted Values for IRT model
fitted.tpm | Fitted Values for IRT model
gh | Gauss-Hermite Quadrature Points
GoF.gpcm | Goodness of Fit for Rasch Models
GoF.rasch | 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
margins | Fit of the model on the margins
margins.gpcm | Fit of the model on the margins
margins.grm | Fit of the model on the margins
margins.ltm | Fit of the model on the margins
margins.rasch | Fit of the model on the margins
margins.tpm | 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.descript | Descriptive Statistics Plot method
plot.fscores | Factor Scores - Ability Estimates Plot method
plot.gpcm | Plot method for fitted IRT models
plot.grm | Plot method for fitted IRT models
plot.ltm | Plot method for fitted IRT models
plot.rasch | Plot method for fitted IRT models
plot.tpm | Plot method for fitted IRT models
rasch | Rasch Model
rcor.test | Pairwise Associations between Items using a Correlation Coefficient
residuals.gpcm | Residuals for IRT models
residuals.grm | Residuals for IRT models
residuals.ltm | Residuals for IRT models
residuals.rasch | Residuals for IRT models
residuals.tpm | Residuals for IRT models
rmvlogis | Generate Random Responses Patterns under Dichotomous and Polytomous IRT models
rmvordlogis | Generate Random Responses Patterns under Dichotomous and Polytomous IRT models
Science | Attitude to Science and Technology
summary.gpcm | Summary method for fitted IRT models
summary.grm | Summary method for fitted IRT models
summary.ltm | Summary method for fitted IRT models
summary.rasch | Summary method for fitted IRT models
summary.tpm | 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.gpcm | vcov method for fitted IRT models
vcov.grm | vcov method for fitted IRT models
vcov.ltm | vcov method for fitted IRT models
vcov.rasch | vcov method for fitted IRT models
vcov.tpm | vcov method for fitted IRT models
WIRS | Workplace Industrial Relation Survey Data