CDM (version 4.8-0)

IRT.modelfit: S3 Methods for Assessing Model Fit

Description

This S3 method asesses global (absolute) model fit using the methods described in modelfit.cor.din.

Usage

IRT.modelfit(object, ...)

## S3 method for class 'din':
IRT.modelfit(object, \dots)
## S3 method for class 'gdina':
IRT.modelfit(object, \dots)

## S3 method for class 'IRT.modelfit.din':
summary(object, \dots)
## S3 method for class 'IRT.modelfit.gdina':
summary(object, \dots)

Arguments

object

Object of classes din or gdina.

...

More arguments to be passed.

Value

• See output of modelfit.cor.din.

See Also

For extracting the individual likelihood or posterior see IRT.likelihood or IRT.posterior. The model fit of objects of class gdm can be obtained by using the TAM::tam.modelfit.IRT function in the TAM package.

Examples

#############################################################################
# EXAMPLE 1: Absolute model fit
#############################################################################
data(sim.dina)
data(sim.qmatrix)

#*** Model 1: DINA model for DINA simulated data
mod1 <- din(sim.dina, q.matr = sim.qmatrix, rule = "DINA" )
fmod1 <- IRT.modelfit( mod1 )
summary(fmod1)
  ##  Test of Global Model Fit
  ##         type value     p
  ##  1   max(X2) 8.728 0.113
  ##  2 abs(fcor) 0.143 0.080
  ##  
  ##  Fit Statistics
  ##                    est
  ##  MADcor          0.030
  ##  SRMSR           0.040
  ##  100*MADRESIDCOV 0.671
  ##  MADQ3           0.062
  ##  MADaQ3          0.059

#*** Model 2: GDINA model
mod2 <- gdina( sim.dina , q.matr = sim.qmatrix , rule="GDINA" )
fmod2 <- IRT.modelfit( mod2 )
summary(fmod2)
  ##  Test of Global Model Fit
  ##         type value p
  ##  1   max(X2) 2.397 1
  ##  2 abs(fcor) 0.078 1
  ##  
  ##  Fit Statistics
  ##                    est
  ##  MADcor          0.023
  ##  SRMSR           0.030
  ##  100*MADRESIDCOV 0.515
  ##  MADQ3           0.075
  ##  MADaQ3          0.071