icrfG {lazy.irt}

R Documentation

Calculation of Item Response Function of Graded Response Items

Description

Calculation of Item Response Function of Graded Response Items

Usage

icrfG(param, theta, smallP = 0, print = 0, plot = 0, debug = 0)

Arguments

param	Item Parameter Data Frame
theta	Discrete theta values
smallP	Minimum value of probability
print	= 1 to print result
plot	= 1 to plot result
debug	= 1 to print intemediate result

Details

An Example of Item Parameter datastet: maxncat = 5
Note that the subscript of the b-parameter ranges between
1 and ncat-1 (= maxscore) (We set c0=0.)

name ncat A b1 b2 b3 b4

Item1 2 1.0 0.0 . . .
Item2 2 1.0 0.0 . . .
Item3 3 1.5 -1.0 0.0 . .
Item4 4 1.5 -1.0 0.0 1.0 .
Item5 5 1.5 -1.0 0.0 1.0 2.0

Value

list
P length(theta) x sum(ncat) ICRF matrix
PP length(theta) x sum(ncat) ICBRF matrix
Pt length(theta) x nitems item response function
fromP, toP indexes of each ICRF in P
fromPP, toPP indexes of each ICBRF in PP

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