Item Response Theory Observed Score Equating Performance in the Presence of Differential Item Parameter Drift

• In Event: 52.083 - Roundtable Session 19
  In Roundtable Session: 52.083-19 - Advances in Differential Item Functioning Research

Abstract

Little research has focused on item parameter drift’s (IPD) impact on equating, and even less is known about differential IPD (DIPD). This study examined the impact of IPD and DIPD on the quality of different observed score IRT equating functions. The data were simulated in order to represent test responses from different administrations over five time points. The results of the study revealed that in that concurrent calibration IRT observed score equating performed better than IRT observed score equating using Stocking and Lord linking when the magnitude of parameter drift was high and the number of items that had IPD were high. It was harder to determine which method was superior when looking at the DIPD results.

Author

• Brooke Milstead, Buros Center For Testing