Effects of Variations in Item Step Values on Item and Test Information in the Partial Credit Model

Abstract

Simulated data were used to investigate systemati cally the impact of various orderings of step difficul ties on the distribution of item information for the par tial credit model. It was found that the distribution of information for an item was a function of (1) the range of the step difficulty values, (2) the number of step difficulties that were out of sequential order, and (3) the distance between the step values that were out of order. Also, by using relative efficiency compari sons, the relationship between the step estimates and the distribution of item information was used to dem onstrate the effects of various test revisions (through the addition and/or deletion of items with specific step characteristics) on the resulting test's precision of measurement. The usefulness of item and test infor mation functions for specific measurement applications of the partial credit model is also discussed.

Get full access to this article

View all access options for this article.

References

Birnbaum, A. (1968). Some latent trait models and their use in inferring an examinee's ability. In F. M. Lord & M. R. Novick, Statistical theories of mental test scores. Reading MA: Addison-Wesley.

Bock, R.D. (1972). Estimating item parameters and latent trait ability when responses are scored in two or more nominal categories. Psychometrika, 37, 29-51.

Dodd, B.G. (1985). Attitude scaling: A comparison of the graded response and partial credit latent trait models (Doctoral dissertation, University of Texas at Austin, 1984). Dissertation Abstracts International , 45, 2074A.

Dodd, B.G. , & Koch, W.R. (1985, April). Item and scale information functions for the partial credit model. Paper presented at the annual meeting of the American Educational Research Association, Chicago.

Koch, W.R. (1983). Likert scaling using the graded response latent trait model. Applied Psychological Measurement, 7, 15-32.

Koch, W.R. , & Dodd, B.G. (1985, April). Computerized adaptive attitude measurement . Paper presented at the annual meeting of the American Educational Research Association, Chicago.

Koch, W.R. , & Dodd, B.G. (1986, April). Operational characteristics of adaptive testing procedures using partial credit scoring. Paper presented at the annual meeting of the American Educational Research Association, San Francisco.

Lord, F.M. (1980). Applications of item response theory to practical testing problems. Hillsdale NJ: Erlbaum.

Masters, G.N. (1981, April). A Rasch model for partial credit scoring . Paper presented at the annual meeting of the American Educational Research Association, Los Angeles .

10.

Masters, G.N. (1982). A Rasch model for partial credit scoring. Psychometrika, 47, 149-174.

11.

Masters, G.N. (1984). Constructing an item bank using partial credit scoring. Journal of Educational Measurement, 21, 19-32.

12.

Samejima, F. (1969). Estimation of latent ability using a response pattern of graded scores. Psychometrika Monograph Supplement , No. 17.

13.

Samejima, F. (1976). Graded response model of the latent trait theory and tailored testing. In C. K. dark (Ed.), Proceedings of the First Conference on Computerized Adaptive Testing. Washington DC: U.S. Government Printing Office.

14.

Thissen, D.M. (1976). Information in wrong responses to Raven progressive matrices. Journal of Educational Measurement, 13, 201-214.