Research On Web-based Computerized Adaptive Testing System

With the development of educational measurement theory and computer network technology, there are some underlying changes in educational examination system in China, from traditional fixed testing based on Classical Test Theory(CTT) to Computerized Adaptive Testing(CAT) based on Item Response Theory(IRT).In Computerized Adaptive Testing (CAT), tests are automatically tailored to the proficiency level of the individual examinees, and the testing result is independent of examination items. CAT can measure the real capacities of the examinees more exactly, more impersonality, and reduce the number of questions and shorten the test without affecting the reliability of the test. So, CAT will be the mainstream of thefuture examinations.At first, this paper analyses status quo and the latest development of CAT (especially Web-based CAT). Then, formulates concretely the main comprehension of the IRT-the theory basis of CAT, and gives a description about the implement method of CAT, briefly explains flow and arithmetic of CAT.After that, as a example of a practical Web-based CAT system-"Mathematics" CAT system for high school, this paper introduces its design thought and exploitation flow, analyses in detail the system structure and exploiting technology, fine design of the system modules, and some key problems (such as item selection and ability estimation) and correlative arithmetic, stressing on the implement of testing module. And then, the author takes a statistic and analyze according to the testing data of this CAT system.In the end of this paper, the author summarizes the strongpoint of this CAT system, points out the problems that need betterment and extension, and gives out a further research direction.