DFIT (version 1.1)

DeltaMhIrt: Obtains the ETS Delta measure for Mantel-Haneszel DIF statistic effect size.

Description

Obtains the ETS Delta measure for Mantel-Haneszel DIF statistic effect size.

Usage

DeltaMhIrt(mh, logistic = FALSE)

Arguments

mh

A numeric vector containing the MH statistic values

logistic

A logical indicating whether the logistic or the normal metric should be used.

Value

delta A numeric vector containing the delta values

References

Holland, P.W., and Thayer, D.T. (1988). Differential Item Performance and the Mantel-Haenszel Procedure. In H. Wainer and H.I. Braun (Eds.), Test Validity. Hillsdale, NJ: Erlbaum.

Examples

# NOT RUN {
data(dichotomousItemParameters)
threePlParameters <- dichotomousItemParameters
isNot3Pl          <- ((dichotomousItemParameters[['focal']][, 3] == 0) |
                      (dichotomousItemParameters[['reference']][, 3] == 0))

threePlParameters[['focal']]          <- threePlParameters[['focal']][!isNot3Pl, ]
threePlParameters[['reference']]      <- threePlParameters[['reference']][!isNot3Pl, ]
threePlParameters[['focal']][, 3]     <- threePlParameters[['focal']][, 3] + 0.1
threePlParameters[['reference']][, 3] <- threePlParameters[['reference']][, 3] + 0.1
threePlParameters[['focal']][, 2]     <- threePlParameters[['focal']][, 2] + 1.5
threePlParameters[['reference']][, 2] <- threePlParameters[['reference']][, 2] + 1.5
threePlParameters[['focal']]          <- threePlParameters[['focal']][-c(12, 16, 28), ]
threePlParameters[['reference']]      <- threePlParameters[['reference']][-c(12, 16, 28), ]

threePlMh <- IrtMh(itemParameters = threePlParameters,  irtModel = "3pl",
                   focalDistribution = "norm", referenceDistribution = "norm",
                   focalDistrExtra = list(mean = 0, sd = 1),
                   referenceDistrExtra = list(mean = 0, sd = 1), groupRatio = 1,
                   logistic = FALSE)

delta3pl <- DeltaMhIrt(threePlMh)

# }