Calculation of stratified DIF variance

dif.strata.variance(dif, se.dif, itemcluster)

Arguments

dif

Vector of uniform DIF effects

se.dif

Standard error of uniform DIF effects

itemcluster

Vector of item strata

Value

A list with following entries:

stratadif

Summary statistics of DIF effects within item strata

weighted.DIFSD

Weighted DIF standard deviation

unweigted.DIFSD

DIF standard deviation

References

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 also

See dif.logistic.regression for examples.