按c-分层不定长CAT的研究

有文献研究按c-分层定长CAT，该文研究按c-分层不定长CAT．通过实验对比，得出按c-分层不定长CAT具有以下优越性：(1)能有效控制题目曝光度，考试具有较高的安全性；(2)考生测试项目的内容覆盖符合预设的内容域比例；(3)不定长方法比定长的方法具有更高的效率．另外，我们给出了一个综合评价指标．

Research on c- Stratified CAT with Variable Length

C-stratified is to stratify the items in the pool according to a-parameter and b-parameter with content-blocking. An item is selected which b-parameter is match with the currently estimated trait level. C-stratified can use the items in pool evenly and improve the security of CAT. The results of the experiment indicate that there is some advantage in this CAT: (1) there is more validity in controlling the item exposure, and the test is more security. (2) the target proportions of content area can be fulfilled for all examinees,(3) the variable length CAT is more efficient than the fixed length CAT.