IRT.likelihood: S3 Methods for Extracting of the Individual Likelihood and...

In CDM: Cognitive Diagnosis Modeling

S3 Methods for Extracting of the Individual Likelihood and the Individual Posterior

Description

Functions for extracting the individual likelihood and individual posterior distribution.

Usage

IRT.likelihood(object, ...)

IRT.posterior(object, ...)

## S3 method for class 'din'
IRT.likelihood(object, ...)
## S3 method for class 'din'
IRT.posterior(object, ...)

## S3 method for class 'gdina'
IRT.likelihood(object, ...)
## S3 method for class 'gdina'
IRT.posterior(object, ...)

## S3 method for class 'gdm'
IRT.likelihood(object, ...)
## S3 method for class 'gdm'
IRT.posterior(object, ...)

## S3 method for class 'mcdina'
IRT.likelihood(object, ...)
## S3 method for class 'mcdina'
IRT.posterior(object, ...)

## S3 method for class 'reglca'
IRT.likelihood(object, ...)
## S3 method for class 'reglca'
IRT.posterior(object, ...)

## S3 method for class 'slca'
IRT.likelihood(object, ...)
## S3 method for class 'slca'
IRT.posterior(object, ...)

Arguments

object	Object of classes din, gdina, mcdina, gdm, slca, reglca.
...	More arguments to be passed.

Value

For both functions IRT.likelihood and IRT.posterior, it is a matrix with attributes

theta	Uni- or multidimensional skill space (theta grid in item response models).
prob.theta	Probability distribution of theta
skillspace	Design matrix and estimated parameters for skill space distribution (only for IRT.posterior.slca)
G	Number of groups

See Also

GDINA::indlogLik, GDINA::indlogPost

Examples

#############################################################################
# EXAMPLE 1: Extracting likelihood and posterior from a DINA model
#############################################################################

data(sim.dina, package="CDM")
data(sim.qmatrix, package="CDM")

#*** estimate model
mod1 <- CDM::din( sim.dina, q.matrix=sim.qmatrix, rule="DINA")
#*** extract likelihood
likemod1 <- CDM::IRT.likelihood(mod1)
str(likemod1)
# extract theta
attr(likemod1, "theta" )
#*** extract posterior
pomod1 <- CDM::IRT.posterior( mod1 )
str(pomod1)

CDM documentation built on Aug. 25, 2022, 5:08 p.m.