sirt (version 1.5-0)

dif.strata.variance: Stratified DIF Variance

Description

Calculation of stratified DIF variance

Usage

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.