Design of Computer Adaptive Test System Based on IRT

Abstract

Stating item response theory and computer adaptive test system, analyzing the problems existing in adaptive test system, and proposing the system design idea, taking the establishment of adaptive test system for C language programming design for example, it analyzes the system structure of computer adaptive test system based on IRT as well as the detailed design and realization of main functional module in details. The adaptive test mode is always conducted surrounding the examinees' competence, and all test items are selected automatically from the item bank by the system depending on the examinees' competence: there is a difficult degree distinguished for test items, adjust the difficult degree of test items at any time according to the test accuracy, with strong pertinence, highlight the principal status of examinees and individualized demands, and enhance the validity and reliability of test, so that the test efficiency is improved. The computer adaptive test (CAT) with item response theory (IRT) as a basic theory has caused the extensive concern from each country around the world, which has been promoted gradually in various social aspects: with USA post-graduate entrance examination GRE and GMAT for the educational world; with Nurse National Committee License Test (NNCLT) for the aspect of vocational qualification authentication; with authentication test organized by Novell Company, CCNA authentication test organized by Cisco Company and MCSE adaptive test organized by Microsoft Company in the corporate world. At domestic, the research and application of IRT has caused the extensive concern from the Education Department. Item response theory CAT is built on the basis of modern test theory - item response theory, from the construction of item bank to the extraction of test items, and then to test paper generating and testing until to the final evaluation, it is conducted under the guidance of IRT. Therefore, CAT is identified as the greatest contribution on the test among modern test theory. For item response theory, Hambleton and Swaminathan made the following statement on it: in the test scenario, through the definition of examinee characteristic - namely peculiarity or competence, estimate the examinee's score on such characteristic (referred to as competence score), and predict or explain the item and answering condition by application of such score, explain and predict the examinee's answer. Peculiarity (competence) and item (test item) are two core concepts for IRT, and the main relationship between both items is the major connotation of IRT. The main research content and theoretical support of IRT and computer adaptive test under its guidance include: parameter estimation, test equating, item selection strategy and termination principles. Computer adaptive test