Even when examination forms are carefully designed to be equivalent, some variation in difficulty between forms is likely. Variations in difficulty become especially problematic when the purpose of the examination is to determine whether someone is sufficiently competent to practice a profession or obtain a credential. It is inherently unfair for some candidates to be given harder examinations while others are given easier examinations unless these differences are taken into account. Equating addresses these differences by determining the equivalent passing score on multiple examination forms. Equating is often used in conjunction with scaling but these are actually two different processes. When used together, the equating is performed first followed by the scaling.
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February 22, 2008
