Differential item functioning detection using the multiple indicators, multiple causes method with a pure short anchor

The multiple indicators, multiple causes (MIMIC) method with a pure short anchor was proposed to detect differential item functioning (DIF). A simulation study showed that the MIMIC method with an anchor of 1, 2, 4, or 10 DIF-free items yielded a well-controlled Type I error rate even when such tests contained as many as 40% DIF items. In general, a longer anchor increased the power of DIF detection, and a 4-item anchor was long enough to yield a high power of DIF detection. An iterative MIMIC procedure was proposed to locate a set of DIF-free items to function as a pure anchor so that the MIMIC method could proceed properly. In another simulation study, it was found that this iterative procedure yielded a perfect (or nearly perfect) rate of accuracy in locating a set of up to 4 DIF-free items. Copyright © 2009 Sage Publications.