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ERIC Number: ED453228
Record Type: Non-Journal
Publication Date: 2001-Apr
Pages: 31
Abstractor: N/A
Reference Count: N/A
Effects of Changes in the Examinees' Ability Distribution on the Exposure Control Methods in CAT.
Chang, Shun-Wen; Twu, Bor-Yaun
To satisfy the security requirements of computerized adaptive tests (CATs), efforts have been made to control the exposure rates of optimal items directly by incorporating statistical methods into the item selection procedure. Since differences are likely to occur between the exposure control parameter derivation stage and the operational CAT administrations, the exposure control methods may not fully accomplish the goal of controlling item exposure. This study explored the effects of the distribution changes on the performance of the Sympson and Hetter (SH) (J. Sympson and R. Hetter, 1985) and the Davey and Parshall (DP) (T. Davey and C. Parshall, 1995) procedures and provided an examination of the assertion that the Stocking and Lewis (M. Stocking and C. Lewis, 1998) conditional multinomial (SLC) procedure would function independently of an real examinee population. Simulations were carried out for this study using various combinations of the intended and real ability distributions. The results show that the changes in the examinees' ability distribution affected both SH and DP procedures in their control of the observed maximum exposure rates, and the effects were more profound for the SH method. The performance of the SLC method was demonstrated to be independent of the examinee's ability distributions in the operational CAT administrations. Contains 19 references, 5 tables, and 4 figures. (Author/SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A