IRT.modelfit function

S3 Methods for Assessing Model Fit

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

IRT.modelfit(object, ...)

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

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

Arguments

• object: Object of classes din or gdina.
• ...: More arguments to be passed.

Returns

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

## Not run:

#############################################################################
# EXAMPLE 1: Absolute model fit
#############################################################################

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

#*** Model 1: DINA model for DINA simulated data
mod1 <- CDM::din( sim.dina, q.matrix=sim.qmatrix, rule="DINA" )
fmod1 <- CDM::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 <- CDM::gdina( sim.dina, q.matrix=sim.qmatrix, rule="GDINA" )
fmod2 <- CDM::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
## End(Not run)