The Research And Design Of Web-based Adaptive Testing System

Examination is an important way to measure people's lever of knowledge and skill. It has existed for 2,000 years in China. But the traditional examination is based on classical testing theory and uses fixed items to exam all students. The main defect is that there is inconsistency between some item difficulty and examinee level. Treat both high-lever student and low-lever student as the same. Therefore, the testing result has its inherent high uncertainty. It is incredible to differentiate examinees only by the testing score. Computerized adaptive testing (CAT) which is ascendant examination is comparatively supported by project response theory. The advantage of CAT is that it breaks the uniformity tactics of conventional exam. CAT lies in that item difficulty is always consistent with examinees' acquaintance. Testing usually consumes less time, but the result is more scientific and better.Graduate Record Examination, Graduate for Management and Administration Test, Nurse National Committee License Test, all of them adapt CAT. In China, MSCE of Microsoft and GRE/GMAT has used adaptive testing. But the general situation of using CAT is following: the scale of using CAT is too small; practical CAT, especially, the B/S mode is few; some estimating ability and selected topic tactics is relative out-of-date. Consequently, CAT has a large space for research and extend.On the basis of generally studying the theory related to CAT and technology of database programming and Web design, the paper designs and implements a CAT based on Web. CAT has two core and key questions. Ability estimating method is one key question. In the different step of examination choose the available method of ability estimating. So it hasn't any fixed mode. At the basis of analyze and practical exploration, to the advantage and disadvantage of different ability estimating method, in different ability estimating period, this paper chooses the appropriate method. Item-selected tactics is the other key question. Through comparison lots of methods shows that b-stratification is a good item-selecting method. But according to different examination scale and application background, how many lever should divide is the best? After many researches and experiment comparison, the author gives the best number of item sub-database under three different testing sizes.The article, firstly has introduced the CAT concept, current situation and significant of research, relative theory basis, database designing technology and web designing technology; and then analyze the design of whole system and each module in detail, and occur questions during examination and answering method; at the end of article, give the result for exploration of ability estimating and item-selected tactics through the experiment; finally, make a summary to adaptive testing system and look into the distance for direction of developing and researching in adaptive testing system.