Calculation of stratified DIF variance
dif.strata.variance(dif, se.dif, itemcluster)
Vector of uniform DIF effects
Standard error of uniform DIF effects
Vector of item strata
A list with following entries:
Summary statistics of DIF effects within item strata
Weighted DIF standard deviation
DIF standard deviation
Longford, N. T., Holland, P. W., & Thayer, D. T. (1993). Stability of the MH D-DIF statistics across populations. In P. W. Holland & H. Wainer (Eds.). Differential Item Functioning (pp. 171-196). Hillsdale, NJ: Erlbaum.
See dif.logistic.regression
for examples.