Effect of Chance Success Due to Guessing on Error of Measurement in Multiple-Choice Tests
Donald W. Zimmerman, Richard Hays Williams · Psychological Reports · 1965
Chance success due to guessing is treated as a component of the error variance of a multiple-choice test score. It is shown that for a test of given item structure the minimum standard error of measurement can be estimated by the formula ( N − X ) / a . where N is the total number of items, X is the score, and a is the number of alternative choices per item. The significance of non-independence of true score and this component of error score on multiple-choice tests is discussed.