A Study for Calibration of Item Parameters

• Main Author: 賴信仁
• Other Authors: 何榮桂
• Format: Others
• Language: en_US
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/51821633825578776799

碩士 === 國立臺灣師範大學 === 資訊教育研究所 === 85 === 　The purpose of this study is to develop a procedure of on - line calibration. On - line method for calibrating new item is described. In item response theory (IRT), how to add new items to the original item bank is a complex problem, and it is involved in two issues - item parameter estimation and item parameter equating & linking. In tradition, the item parameters are estimated with ability parameter after a large amount of paper and pencil testing. This is because of the lack of the parameters. But in the above subject, the method is inapposite. Because the examinee''s ability is estimated by adaptive testing, it is thought to be the real one. In the other words, the item parameter could be estimated when the ability is known. The first study of this research is to explore the feasibility of this thought. 　　Besides the issue, it must consider about item parameter equating and linking. For this issue, the anchored item design (Stocking, 1988) is adopted in this study. When the examinee finishes his adaptive testing, there is a nonadaptive testing to the examinee and the work is finished until receiving enough information. When the ending point is reaching, the parameter estimation is occurring. There are six designs for the number of anchored items: 5, 6, 7, 8, 9, and 10 anchored items design. Thest characteristic curve (TCC) method (Stocking & Lord, 1983) is used to implement the linking module. 　　Besides this, the new strategy for anchored items'' selection is approached. There are two consideration about this issue: simple design and discrimination design. The first design selected anchored items with no consideration about discrimination power parameter. The second design contains three selected strategy high discrimination selects highest discriminating paramenters and middle discrimination select the middle ones and low discrimination is opposite to the high one. 　　The results show three facts. The first, the feasibility for on - line calibration is proved. When system collected collected above 500 response patterns of examinees, both of the design (simple and middle discrimination) in 9 anchored items design acquired acceptable results. The second, the higher anchored items design produce more efficient outcomes in simple and middle discrimination design. The last, it is more efficient for high and low discrimination design.