An Illustration of a Mantel-Haenszel Procedure to Flag Misbehaving Common Items in Test Equating

In this study the Mantel-Haenszel procedure, widely used in studies for identifying differential item functioning, is proposed as an alternative to the delta-plot method and applied in a test-equating context for flagging common items that behave differentially across cohorts of examinees. The Mantel-Haenszel procedure has the advantage of conditioning on ability when making comparisons of performance of two examinee groups on an item. There are schemes for interpreting the effect size of differential performance, which can inform the decision as to whether to retain those items in the common-item pool, or to discard them. Data from a statewide assessment are analyzed to illustrate the use of this procedure. Advantages of this methodology are discussed and limitations regarding test design that may make its application difficult are described.