Package: transDIF 0.1.0.9000

transDIF: Score Comparability for Translated and Adapted Exams

An adaptation-comparability workflow for small, lower-scoring and unbalanced language groups where standard differential item functioning (DIF) tools (Magis, Beland, Tuerlinckx and De Boeck, 2010, <doi:10.3758/BRM.42.3.847>) break down. Calibrates the Rasch model in each language group, links the groups robustly through the densest cluster of items rather than assuming DIF cancels out (on anchor selection see Kopf, Zeileis and Strobl, 2015, <doi:10.1177/0013164414529792>), detects small-sample DIF with an empirical-Bayes spike-and-slab model and local false discovery rates (Efron, 2004, <doi:10.1198/016214504000000089>), quantifies whether item-level DIF accumulates into different pass rates, explains DIF by item features to give translators actionable guidance, and drafts a comparability report.

Authors:Daniel Edi [aut, cre, cph]