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The Predicted and Observed Effect of Chance on Multiple-Choice Test Validity

Plumlee, Lynnette B.
Publication Year:
Report Number:
ETS Research Bulletin
Document Type:
Page Count:
Subject/Key Words:
Chance Level Scores, Difficulty Level, Distractors (Tests), Guessing (Tests), Item Analysis, Multiple Choice Tests, Test Validity


The present paper is an extension of an earlier study on the effect of chance success on item and test statistics when answer options are supplied. The earlier study (3) compared values predicted by Guilfords formula for item difficulty (2), Carroll's formula for test reliability (1), and the author's formula for item-test correlation with values obtained in an empirical study using mathematics achievement test material. The present paper presents the equation for predicting the effect of chance success on test validity and compares predicted values with empirical values from the same source of data as that used for the previous study.

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