ERIC Number: ED368791
Record Type: RIE
Publication Date: 1994-Apr
Reference Count: N/A
The Effect of Restricting Ability Distributions in the Estimation of Item Difficulties: Implications for a CAT Implementation.
Ito, Kyoko; Sykes, Robert C.
Responses to previously calibrated items administered in a computerized adaptive testing (CAT) mode may be used to recalibrate the items. This live-data simulation study investigated the possibility, and limitations, of on-line adaptive recalibration of precalibrated items. Responses to items of a Rasch-based paper-and-pencil licensure examination were used to simulate CAT and paper-and-pencil administrations, defining CAT forms of varying difficulty levels and samples of various sizes. Forms were calibrated and new b-values were compared with the bank b-values obtained from responses of the reference group taking the paper-and-pencil examination. Results indicate that bank b-values were not well replicated when difficult items were calibrated using responses from able examinees and easy items were calibrated using responses from less able examinees. On-line adaptive recalibration as simulated in this study has limitations. However, a "modified" on-line adaptive recalibration may still be a possibility as long as: (1) a reasonably large CAT recalibration sample is predefined from the reference group; (2) the sample has a mean ability similar to that of the reference group; and (3) items to be recalibrated together are relatively heterogeneous in Rasch difficulty. Eight tables are included. (Contains 3 references.) (Author/SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A
Identifiers: B Values; Calibration; Paper and Pencil Tests; Rasch Model; Recalibration
Note: Paper presented at the Annual Meeting of the National Council on Measurement in Education (New Orleans, LA, April 5-7, 1994).