The Merits of Multiple-Answer Items as Evaluated by Using Six Scoring Formulas

The indices of item difficulty and discrimination, the coefficients of effective length, and the average item information for both single and multiple-answer items using six different scoring formulas were computed and compared. These formulas vary in terms of the assignment of partial credit and the correction for guessing. Results show that items with multiple answers are substantially more discriminating and reliable when partial credit is given. The formulas without correction for guessing seem to perform at least as well as the formulas with correction.