ERIC Number: ED442801
Record Type: Non-Journal
Publication Date: 2000-Mar
Reference Count: N/A
Estimating Item Parameters from Classical Indices for Item Pool Development with a Computerized Classification Test. ACT Research Report Series.
Huang, Chi-Yu; Kalohn, John C.; Lin, Chuan-Ju; Spray, Judith
Item pools supporting computer-based tests are not always completely calibrated. Occasionally, only a small subset of the items in the pool may have actual calibrations, while the remainder of the items may only have classical item statistics, (e.g., "p"-values, point-biserial correlation coefficients, or biserial correlation coefficients). Transformations can be applied to the classical statistics to obtain rough estimates of the item parameters from a three-parameter logistic item response model. These estimates, in turn, can be improved by linking them to items with actual calibrations from a program such as BILOG. The resulting item parameter estimates can then be used in a computerized classification test (CCT). An evaluation of the results of using such estimated parameters in simulated CCTs is presented in this paper. Seven simulated item pools were used. Results lead to the suggestion that when considering use of such augmented parameter estimates as those produced by the linking procedures in this paper, consideration be given to the sources of possible error and their effects on the outcomes of the test. (Contains 12 tables and 6 figures.) (SLD)
Descriptors: Classification, Computer Assisted Testing, Estimation (Mathematics), Item Banks, Item Response Theory
ACT Research Report Series, P.O. Box 168, Iowa City, IA 52243-0168.
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: American Coll. Testing Program, Iowa City, IA.