D. Thissen et al., ITEM RESPONSE THEORY FOR SCORES ON TESTS INCLUDING POLYTOMOUS ITEMS WITH ORDERED RESPONSES, Applied psychological measurement, 19(1), 1995, pp. 39-49
Item response theory (IRT) provides procedures for scoring tests inclu
ding any combination of rated constructed-response and keyed multiple-
choice items, in that each response pattern is associated with some mo
dal or expected a posteriori estimate of trait level. However, various
considerations that frequently arise in large-scale testing make resp
onse-pattern scoring an undesirable solution. Methods are described ba
sed on IRT that provide scaled scores, or estimates of trait level, fo
r each summed score for rated responses, or for combinations of rated
responses and multiple-choice items. These methods may be used to comb
ine the useful scale properties of IRT-based scores with the practical
virtues of a scale based on a summed score for each examinee.