IRT下题量与被试量对参数估计模拟返真性能的影响  

The Impact that the Number of Items and Examinees Influence Parameter Recovery within IRT

作　　者："基础教育教学质量监测系统"项目组 

机构地区：[1]华南师范大学应用心理研究中心

出　　处：《中国考试》2009年第6期3-10,共8页journal of China Examinations

基　　金：广州市教育局教研室、华南师范大学心理应用研究中心合作项目“基础教育教学质量监测系统”的成果;广东省普通高校人文社会科学“十五”规划研究重点项目的资助(项目号为06JDXMXLX002)。

摘　　要：在项目反应理论下的题库建设时，进行纸笔测验测试时需要多少被试量、题量．试题的参数估计能够达到较为精确估计？本文使用蒙特卡洛模拟方法模拟测验情境．对此问题进行探讨。分析题量的变化和被试量的变化对a、b参数估计的模拟返真性能的影响。1）从被试量角度来看．在两级、多级记分试题模拟测验情境下，随着被试量逐渐增大，项目参数估计值模拟返真指标均方误差逐渐减小。2）从题量角度来看．在两级记分试题模拟情境下，均方误差曲线在题量为25题左右时有一个拐点，即当题量小于25题时．随着题量增加时RMSE减小幅度较大，而当题量大干25题时，这时再增加题量，RMSE减小幅度很小。在多级记分试题模拟情境下，均方误差曲线在题量为15题左右时有一个拐点，即当题量小于15题时．随着题量增加．RMSE逐渐减小，当题量大于15题时，随着题量增加，RMSE逐渐增大。When we construct item bank within IRT, what number of the items and examinees the paper and pencil test need, so as to estimating the item parameter accurately. In the issue, the author simulate different test cases using the method of Monte Carlo simulation, and analyze how the change of the number of items and examinees influence parameter recovery of a, b parameter. 1 ）From the angle of the number of examinees, in the test cases that composed of the dichotomous or polytomous items, the index of parameter recovery, RMSE become wane as the number of items augments. 2）From the angle of the number of items, in the test cases which composed of the dichotomous items, there is an inflexion on the RMSE curve as the number of the items is 25. When the number of item is smaller than 25, the value of RMSE diminish rapidly; meanwhile, when the number of item is bigger than 25, the value of RMSE diminish slightly. In the test cases which composed of the polytomous items, there is an inflexion on the RMSE curve as the number of the items is 15. When the number of item is smaller than 15, the value of RMSE diminish; meanwhile, when the number of item is bigger than 15, the value of RMSE increase.

关 键 词：题量 被试量 蒙特卡洛模拟 模拟返真性能 均方误差RMSE 

分 类 号：G405[文化科学—教育学原理]