Long-Term Differential Item Functioning Effect on Common-Item Nonequivalent Groups Design Equating

• In Event: Westin Roundtable Session 2

Abstract

We will investigate the effects of differential item functioning (DIF) on equating coefficients and item parameters recovery under common-item nonequivalent groups equating design using Monte Carlo simulation. The factors to be explored include sample size, different ratios of common items, different ratios of DIF items, different forms of DIF, and different magnitudes of DIF between non-equivalent groups. Preliminary results showed that DIF effects on equating coefficients and item parameter recovery varied with sample size, number of common items, number of DIF items, magnitudes of DIF, and forms of DIF.

Authors

• Huan Wang, Office of the Vice Provost for Advances in Learning at Harvard University

• Myeongsun Yoon, Texas A&M University