Differential Item Functioning In the External and Internalized Shame Scale for Eating Disorders (EISS-ED): An IRT Analysis of Fairness across Clinical Status and Gender

We applied IRT-based DIF analyses to a 12-item measure of internal and external shame related to eating behavior to assess item-level fairness across clinical status and gender. Only a few items showed meaningful DIF. Bootstrap-derived cutoffs improved detection accuracy, supporting strong overall validity, with only a few areas requiring refinement.