TAM: anova.tam – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

anova.tam

Likelihood Ratio Test for Model Comparisons and Log-Likelihood Value

Description

The anova function compares two models estimated of class tam, tam.mml or tam.mml.3pl using a likelihood ratio test. The logLik function extracts the value of the log-Likelihood.

The function can be applied for values of tam.mml, tam.mml.2pl, tam.mml.mfr, tam.fa, tam.mml.3pl, tam.latreg or tamaan.

Usage

## S3 method for class 'tam'
anova(object, ...)
## S3 method for class 'tam'
logLik(object, ...)

## S3 method for class 'tam.mml'
anova(object, ...)
## S3 method for class 'tam.mml'
logLik(object, ...)

## S3 method for class 'tam.mml.3pl'
anova(object, ...)
## S3 method for class 'tam.mml.3pl'
logLik(object, ...)

## S3 method for class 'tamaan'
anova(object, ...)
## S3 method for class 'tamaan'
logLik(object, ...)

## S3 method for class 'tam.latreg'
anova(object, ...)
## S3 method for class 'tam.latreg'
logLik(object, ...)

## S3 method for class 'tam.np'
anova(object, ...)
## S3 method for class 'tam.np'
logLik(object, ...)

Arguments

`object`	Object of class `tam`, `tam.mml`, `tam.mml.3pl`, `tam.latreg`, `tam.np`, or `tamaan`. Note that for `anova` two objects (fitted models) must be provided.
`...`	Further arguments to be passed

Value

A data frame containing the likelihood ratio test statistic and information criteria.

Examples

#############################################################################
# EXAMPLE 1: Dichotomous data sim.rasch - 1PL vs. 2PL model
#############################################################################

data(data.sim.rasch)
# 1PL estimation
mod1 <- TAM::tam.mml(resp=data.sim.rasch)
logLik(mod1)
# 2PL estimation
mod2 <- TAM::tam.mml.2pl(resp=data.sim.rasch, irtmodel="2PL")
logLik(mod2)
# Model comparison
anova( mod1, mod2 )
  ##     Model   loglike Deviance Npars      AIC      BIC    Chisq df       p
  ##   1  mod1 -42077.88 84155.77    41 84278.77 84467.40 54.05078 39 0.05508
  ##   2  mod2 -42050.86 84101.72    80 84341.72 84709.79       NA NA      NA

## Not run: 
#############################################################################
# EXAMPLE 2: Dataset reading (sirt package): 1- vs. 2-dimensional model
#############################################################################

data(data.read,package="sirt")

# 1-dimensional model
mod1 <- TAM::tam.mml.2pl(resp=data.read )
# 2-dimensional model
mod2 <- TAM::tam.fa(resp=data.read, irtmodel="efa", nfactors=2,
             control=list(maxiter=150) )
# Model comparison
anova( mod1, mod2 )
  ##       Model   loglike Deviance Npars      AIC      BIC    Chisq df  p
  ##   1    mod1 -1954.888 3909.777    24 3957.777 4048.809 76.66491 11  0
  ##   2    mod2 -1916.556 3833.112    35 3903.112 4035.867       NA NA NA

## End(Not run)

TAM

Test Analysis Modules

v3.6-45

GPL (>= 2)

Authors

Alexander Robitzsch [aut,cre] (<https://orcid.org/0000-0002-8226-3132>), Thomas Kiefer [aut], Margaret Wu [aut]

Initial release

2021-04-22 14:35:52