Calculation of stratified DIF variance
dif.strata.variance(dif, se.dif, itemcluster)
A list with following entries:
Summary statistics of DIF effects within item strata
Weighted DIF standard deviation
DIF standard deviation
Vector of uniform DIF effects
Standard error of uniform DIF effects
Vector of item strata
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.