TAM (version 0.04-43)

tam.fit: Item Infit and Outfit Statistic

Description

The item infit and outfit statistic are calculated for objects of classes tam, tam.mml and tam.jml, respectively.

Usage

tam.fit(tamobj, ...)
tam.mml.fit(tamobj, FitMatrix=NULL, progress=FALSE)

Arguments

tamobj

An object of class tam, tam.mml or tam.jml

FitMatrix

A fit matrix for a specific hypothesis of fit (EXPLAIN IT IN DETAIL)

progress

Display progress in fit calculation?

...

Further arguments to be passed

Value

• In case of tam.mml.fit a data frame with four columns:
• Outfit
  Item outfit statistic
• Outfit_t
  The $t$ value for the outfit statistic
• Infit
  Item infit statistic
• Infit_t
  The $t$ value for the infit statistic

Details

Item fit is automatically calculated in JML estimation using tam.jml.

Examples

data(sim.rasch)
# estimate Rasch model
mod1 <- tam.mml(resp=sim.rasch) 
# item fit
fit1 <- tam.fit( mod1 )
##   > print( round( fit1 ,3 ))
##       Outfit Outfit_t Infit Infit_t
##   I1   0.951   -1.549 0.994  -0.135
##   I2   1.033    1.040 1.028   0.755
##   I3   1.012    0.387 1.009   0.273
##   I4   1.041    1.296 1.057   1.614