TY - JOUR AU1 - Reckase, Mark D. AB - Many test items require more than one ability to obtain a correct response. This article proposes a mul tidimensional index of item difficulty that can be used with items of this type. The proposed index describes multidimensional item difficulty as the direction in the multidimensional space in which the item provides the most information and the distance in that direction to the most informative point. The multidimensional dif ficulty is derived for a particular item response theory model and an example of its application is given using the ACT Mathematics Usage Test. TI - The Difficulty of Test Items That Measure More Than One Ability JF - Applied Psychological Measurement DO - 10.1177/014662168500900409 DA - 1985-12-01 UR - https://www.deepdyve.com/lp/sage/the-difficulty-of-test-items-that-measure-more-than-one-ability-OYZotiI0q7 SP - 401 EP - 412 VL - 9 IS - 4 DP - DeepDyve ER -