The concept of assigning partial credit on multiple-choice test items is considered for items from ACS Exams. Because the items on these exams, particularly the quantitative items, use common student errors to define incorrect answers, it is possible to assign partial credits to some of these incorrect responses. To do so, however, it becomes vital that instructors reach general agreement as to the level of partial credit. Using workshops with instructors, ACS Exams has identified reasons why partial credit could be assigned in an exam set of 70 test items. With partial-credit assignments thus established, polytomous scoring is applied and the effect of such scoring on the overall norm-referenced psychometrics is determined and described. While individual students move within the overall norm, the average influence of polytomous scoring as conceived by the workshops does not substantially change the ability to do norm-based comparisons.
Available at: http://works.bepress.com/thomas_holme/25/