fitP2G {lazy.irt}R Documentation

Approximate Conversion of Graded Response Items to Partial Credit Items Using Logit Transformation

Description

Approximate Conversion of Graded Response Items to Partial Credit Items Using Logit Transformation

Usage

fitP2G(paramG, wtype = 1, DinP = 1, dataframe = 1, npoints = 21,
  thmin = -3, thmax = 3, maxabsv = 3, print = 1, plot = 0,
  debug = 0)

Arguments

paramG

Item Parameter Data Frame for Graded Response Items

wtype

= 1 to use normal weight, else uniform

DinP

= 1 to include D=1.7 in logistic function

dataframe

= 1 to create parameter data frame, not matrix

npoints

# of discrete points for theta

thmin

Minimum value of discrete thata value

thmax

Maximum value of discrete thata value

maxabsv

Maximum absolute value of the weight

print

= 1 to print result

plot

= 1 to plot result

debug

= 1 to print intemediate result

Value

A list of: Partial Credit Model Item Parameter Data Frame in Nominal Format
Partial Credit Model Item Parameter Data Frame in Nominal Format0
Partial Credit Model Item Parameter Data Frame in Standard Format

Examples

paramP1 <- fitP2G( paramS1[3,], npoints=21, plot=1, print=1 )$paramP
paramG1 <- fitG2P( paramP1, npoints=21, plot=1, print=1 )




[Package lazy.irt version 0.1.3 Index]