Q3.testlet: Q_3 Statistic of Yen (1984) for Testlets

In sirt: Supplementary Item Response Theory Models

Q_3 Statistic of Yen (1984) for Testlets

Description

This function calculates the average Q_3 statistic (Yen, 1984) within and between testlets.

Usage

Q3.testlet(q3.res, testlet.matrix, progress=TRUE)

Arguments

q3.res	An object generated by Q3
testlet.matrix	A matrix with two columns. The first column contains names of the testlets and the second names of the items. See the examples for the definition of such matrices.
progress	Logical indicating whether computation progress should be displayed.

Value

A list with following entries

testlet.q3	Data frame with average Q_3 statistics within testlets
testlet.q3.korr	Matrix of average Q_3 statistics within and between testlets

References

Yen, W. M. (1984). Effects of local item dependence on the fit and equating performance of the three-parameter logistic model. Applied Psychological Measurement, 8, 125-145.

See Also

For estimating all Q_3 statistics between item pairs use Q3.

Examples

#############################################################################
# EXAMPLE 1: data.read. The 12 items are arranged in 4 testlets
#############################################################################
data(data.read)

# estimate the Rasch model
mod <- sirt::rasch.mml2( data.read)
mod$item

# estmate WLEs
mod.wle <- sirt::wle.rasch( dat=data.read, b=mod$item$b )

# Yen's Q3 statistic
mod.q3 <- sirt::Q3( dat=data.read, theta=mod.wle$theta, b=mod$item$b )

# Yen's Q3 statistic with testlets
items <- colnames(data.read)
testlet.matrix <- cbind( substring(  items,1,1), items )
mod.testletq3 <- sirt::Q3.testlet( q3.res=mod.q3,testlet.matrix=testlet.matrix)
mod.testletq3

sirt documentation built on May 29, 2024, 8:43 a.m.