mstSIB {mstDIF}

The mstSIB test for MSTs

Description

This function allows the detection of itemwise DIF using the mstSIB test.

Usage

mstSIB(
  resp,
  DIF_covariate,
  theta = NULL,
  see = NULL,
  cellmin = 3,
  pctmin = 0.9,
  NCell = 80
)

Arguments

resp

A data frame containing the response matrix. Rows correspond to respondents, columns to items.

DIF_covariate

A vector indicating the membership to the reference (0) and focal (1) groups.

theta

A vector of ability estimates for each respondent.

see

A vector of the standard error of the ability estimates for each respondent.

cellmin

Minimum number of respondents per cell for the focal and reference group. Cells with fewer respondents are discarded.

pctmin

Minimum rate of focal and reference group that should be used for estimating the over ability difference between focal and groups after discarding cells with few respondents.

NCell

The initial number of cells for estimating the overall ability difference between the focal and reference groups.

Details

Author: Mark J. Gierl, with minor changes by Rudolf Debelak and Dries Debeer

Value

A list with four elements. The first element is the response matrix, the second element is the name of the DIF covariate, and the third element is the name of the test. The fourth element is a matrix where each row corresponds to an item. The columns correspond to the following entries:

Beta

The estimated weighted ability difference between the focal and reference groups.

Vars

The estimation error of the weighted ability difference between the focal and reference groups.

N_R

The number of respondents in the reference group.

N_F

The number of respondents in the focal group.

NCell

The initial number of cells for estimating the overall ability difference between the focal and reference groups.

p_value

The p-value of the null hypothesis that the ability difference between the focal and reference groups is 0.

Examples

data("toydata")
resp <- toydata$resp
group_categ <- toydata$group_categ
theta_est <- toydata$theta_est
see_est <- toydata$see_est
mstSIB(resp = as.data.frame(resp), theta = theta_est,
DIF_covariate = group_categ, see = see_est)