Systematic Construction of Distractors for Ability and Achievement Test Items

DISTRACTORS, according to the definition given by English and English (1958), dquo;are designed to be attractive... to the respond-ent who does not know the correct answer.dquo; Keeping the correct answer company is usually regarded the only function of dis-tractors, and sufficient attraction is deemed sufficient qualification for being a good distractor. Hence, distractors are usually con-structed initially on the basis of intuition as to what answer might be attractive, or else by gleaning answers from tests which are first presented in open-ended form. By contrast, it will be argued here that distractors can be constructed in a systematic fashion on an a priori basis, which provides at least three desirable fea-tures not possessed by less systematic approaches: 1. Successful prediction of relative empirical difficulties of dis-tractors, 2. Reduction of variation in test results due to undesired factors, 3. Possibility of differential scorings of subjects on the types of wrong answers to which they are attracted. These features may enable construction of tests of shorter length than usual for desired reliability and validity, and increase the possibilities of using a test for diagnostic and remedial purposes with respect to habitual errors of individual subjects.