The next step depends on whether one wishes to use a constrained baseline (all other) method or a free baseline (constant anchor) method to perform model comparisons (Stark, Chernyshenko, & Drasgow, 2006; Wang & Shih, 2010; Wang & Yeh, 2004). Most MIMIC DIF research has been conducted using the constrained baseline method in which items are tested for uniform DIF, associated with group differences in item thresholds (