Determining a correct response to many test items frequently requires more than one ability. This paper describes the characteristics of items of this type by proposing generalizations of the item response theory concepts of discrimination and information. The conceptual framework for these statistics is presented, and the formulas for the statistics are derived for the multidimensional extension of the two-parameter logistic model. Use of the statistics is demonstrated for a form of the ACT Mathematics Usage Test.
American College Testing. (1982). The ACT Assessment Form 24B. Iowa City IA: American College Testing.
2.
McKinley, R.L., & Reckase, M.D. (1982). The use of the general Rasch model with multidimensional item response data (Research Rep. ONR 82-1). Iowa City IA: American College Testing.
3.
McKinley, R.L., & Reckase, M.D. (1983). MAXLOG: A computer program for the estimation of the parameters of a multidimensional logistic model. Behavior Research Methods and Instrumentation, 15, 389-390.
4.
Reckase, M.D. (1985). The difficulty of test items that measure more than one ability. Applied Psychological Measurement, 9, 401-412.
5.
Sympson, J.B. (1978). A model for testing with multidimensional items . In D. J. Weiss (Ed.), Proceedings of the 1977 Computerized Adaptive Testing Conference (pp. 82-98). Minneapolis: University of Minnesota, Department of Psychology, Computerized Adaptive Testing Laboratory.
