ERIC Number: ED429997
Record Type: RIE
Publication Date: 1999-Apr
Adjusting Computer Adaptive Test Starting Points To Conserve Item Pool.
Zhu, Daming; Fan, Meichu
The convention for selecting starting points (that is, initial items) on a computerized adaptive test (CAT) is to choose as starting points items of medium difficulty for all examinees. Selecting a starting point based on prior information about an individual's ability was first suggested many years ago, but has been believed unimportant provided that the CAT is reasonably long. However, starting with a medium difficulty item for all examinees has two potential disadvantages: unnecessary uses of the first one or two items and overuse or overexposure of the items around the medium difficulty. This study analyzed simulated CAT results and suggests significant benefits from administering the first CAT item at a difficulty level suitable to each examinee. Such an adjustment can reduce the use of items around the medium difficulty in the item pool, providing extra help in controlling the exposure rate of the items beyond what standard exposure control methods can achieve. The effect of selecting examinee-appropriate starting points can vary depending on the quality of the information used about examinees' ability levels and the test termination rules applied. (Contains 3 tables, 26 figures, and 8 references.) (Author)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A
Note: Paper presented at the Annual Meeting of the American Educational Research Association (Montreal, Quebec, Canada, April 19-23, 1999).