"双减"背景下计算机化自适应多阶段测试的设计与算法改进

计算机化自适应多阶段测试是精准减负的一种有效手段,因为它会自动引导学生尽可能作答与其能力水平相适应的题目,从而节省出作答太难或太易题目所浪费的大量时间和精力.不过,我国目前的一些计算机测试系统缺乏现代测评技术的有力支撑,部分题库在知识内容和能力维度的标识与编码、题目参数的估计与等值,以及分数的算法与使用方面存在着较大缺陷.本文简要分析了自适应测试的基本模式、操作流程、使用条件和主要优点,具体讨论了计算机化自适应多阶段测试系统的设计,以及基于测验总分的单参数logistic模型和基于作答反应模式的双参数logistic模型的算分方法,为提升计算机化自适应测试的水平,进而促进教师因材施教、减轻学生作业负担和考试负担提供了考试科学视角下的新办法.     

A Conditional Exposure Control Method for Multidimensional Adaptive Testing

In computerized adaptive testing (CAT), ensuring the security of test items is a crucial practical consideration. A common approach to reducing item theft is to define maximum item exposure rates, i.e., to limit the proportion of examinees to whom a given item can be administered. Numerous methods for controlling exposure rates have been proposed for tests employing the unidimensional 3-PL model. The present article explores the issues associated with controlling exposure rates when a multidimensional item response theory (MIRT) model is utilized and exposure rates must be controlled conditional upon ability. This situation is complicated by the exponentially increasing number of possible ability values in multiple dimensions. The article introduces a new procedure, called the generalized Stocking-Lewis method, that controls the exposure rate for students of comparable ability as well as with respect to the overall population. A realistic simulation set compares the new method with three other approaches: Kullback-Leibler information with no exposure control, Kullback-Leibler information with unconditional Sympson-Hetter exposure control, and random item selection.     

Evaluating Content Alignment in Computerized Adaptive Testing

The alignment between a test and the content domain it measures represents key evidence for the validation of test score inferences. Although procedures have been developed for evaluating the content alignment of linear tests, these procedures are not readily applicable to computerized adaptive tests (CATs), which require large item pools and do not use fixed test forms. This article describes the decisions made in the development of CATs that influence and might threaten content alignment. It outlines a process for evaluating alignment that is sensitive to these threats and gives an empirical example of the process.     

Practical issues in Large-Scale Computerized Adaptive Testing

Computerized adaptive testing, although well-grounded in psychometric theory, has had few large-scale applications in the past. This is now changing because the cost of computing has declined rapidly. As is always true at such junctures where theory is translated into practice, many practical issues arise that must now be addressed. In this article, we discuss a number of such issues and sketch out potential problems and potential solutions. Our purpose is to encourage further development of solutions to the issues presented as well as other practical issues facing measurement professionals involved with the implementation of adaptive testing.     

Item Selection and Exposure Control Methods for Computerized Adaptive Testing with Multidimensional Ranking Items

The use of computerized adaptive testing algorithms for ranking items (e.g., college preferences, career choices) involves two major challenges: unacceptably high computation times (selecting from a large item pool with many dimensions) and biased results (enhanced preferences or intensified examinee responses because of repeated statements across items). To address these issues, we introduce subpool partition strategies for item selection and within-person statement exposure control procedures. Simulations showed that the multinomial method reduces computation time while maintaining measurement precision. Both the freeze and revised Sympson-Hetter online (RSHO) methods controlled the statement exposure rate; RSHO sacrificed some measurement precision but increased pool use. Furthermore, preventing a statement's repetition on consecutive items neither hindered the effectiveness of the freeze or RSHO method nor reduced measurement precision.     

Computerized Adaptive Testing With Different Groups

How does the use of computerized adaptive testing affect the performance of students from different groups? How consistent were the results of computerized adaptive and “conventional” tests? What did the students think about the test experience? What advice do the authors have for test developers and users?     

CDMA直放站隔离度自适应检测方法

直放站的使用虽然有很多优点怛是当收发天线隔离度不够时会出现自激现象,对网络造成严重影响。因此本文主要实现对CDMA直放站收发天线之间隔离度检测功能。当CDMA直放站天线隔离度低干直放站正常工作所要求时,检测出当前实际天线隔离度大小,并根据当前实际天线隔离度大小提出了自适应的隔离度检测算法,消除CDMA直放站自激现象,提高系统性能。     

An Introduction to the Computerized Adaptive Testing

The computerized adaptive testing （CAT） has unsurpassable advantages over the traditional testing. It has become the mainstream in large scale examination in modem society. This paper gives a brief introduction to CAT including differences between traditional testing and CAT, the principals of CAT works, Psychometric theory and computer algorithms of CAT, the advantages and cautions of CAT. In the end, the development of CAT in China is reviewed.     

英语词汇自适应测试系统中词汇难度的判定

针对英语词汇自适应测试系统中词汇难度如何量化的现实需求,文章提出了从词频、长度、语音书写和谐程度这三个维度来量化英语词汇难度的具体方法,并以普通高中英语词汇为例展示了其量化过程。经过对各个难度子区间的词汇频次进行统计后发现,其结果近似呈现正态分布。     

Adapting Adaptive Testing: Using the MicroCAT Testing System in a Local School District

What is the rationale for adapting an existing testing system instead of developing your own? What are the limitations of MicroCAT? What has to be modified in order to meet local needs and to realize the potential of adaptive testing in the context of an existing testing system?     

加强生物实验教学提高学生实验技能

随着新课程标准的实施,在新编生物教学大纲中,注重了理论和实践相结合的原则,教材内容突出表现三多即实验内容多,实验形式多,实验要求多的特点.在生物实验教学中,为使每个实验达到教学大纲的要求,必须加大生物实验教学的力度,强化实验规则和技能.     

基于WEB的计算机自适应考试系统的设计与实现

介绍了项目反应理论(IRT)的基本理论和计算机化自适应测试(CAT)的实现过程。并在Visual Stu-dio.net2003的环境下,以SQL作为后台数据库,以三参数Logistic模型为项目反应模型,开发了一个基于WEB的CAT系统。     

A New Stopping Rule for Computerized Adaptive Testing

The goal of the current study was to introduce a new stopping rule for computerized adaptive testing. The predicted standard error reduction stopping rule (PSER) uses the predictive posterior variance to determine the reduction in standard error that would result from the administration of additional items. The performance of the PSER was compared to that of the minimum standard error stopping rule and a modified version of the minimum information stopping rule in a series of simulated adaptive tests, drawn from a number of item pools. Results indicate that the PSER makes efficient use of CAT item pools, administering fewer items when predictive gains in information are small and increasing measurement precision when information is abundant.     

试论完善普通话水平测试机制的有效途径

普通话水平测试是一项国家级的测试,属于政府行为。要保证普通话水平测试的信度和效度,必须从以下几个方面完善它的机制：1．建立完整的试题库,实行教考分离的原则;2．细化评分的标准,使评分有据可依;3．加强测试员队伍的培养和考核;4．加强考前辅导工作,做好考后复审工作;5．启动大中小学教师队伍的测试工作,为以后公务员的测试做好准备。     

基于Grails的在线自适应测试系统的设计与实现

本文主要介绍如何运用Grails框架进行快速Web应用开发。文章首先简单介绍了Grails框架开发环境;然后,在分析GrailsMVC模式实现和自适应考试系统原理的基础上,采用用例分析技术和领域模型驱动模式,基于Grails框架设计实现了一个自适应测试系统;最后,还针对安全权限控制和国际化等问题充分利用Grails插件给出了相应的解决方案。系统经过两年的运行取得良好效果,且在不断改进中。     

Adaptive Testing: The Evolution of a Good Idea

The psychometric requirements for adaptive testing are reviewed and the historical antecedents are considered. An analysis of these two factors reveals the importance of the concept of the item/person interaction. Future areas for advancement of adaptive testing are discussed.     

计算机化自适应测验(CAT)的发展和前景展望(续)

三、CAT中对的估计(一)MLE(极大似然估计法)假设一个能力水平为θ的被试对n道项目X_1,X_2,…,X_n作答。θ的估计可以通过使(8)式所示的似然函数最大化的方式来得到。令(?)_n为此时所得的θ估计。显然(?)_n也是(9)式的极大似然估计。已知在一定的条件下,(?)_n符合渐进正态,其均值为θ,方差近似为I~(-1)_n((?)_n)。目前的CAT设计大多通过递归方式在被试回答一个新的项目之后得到最新的θ估计,并根据信息最大化法抽取下一个项目。     

认知诊断自适应测试的应用与展望

基于认知诊断自适应测试(CD-CAT)的教育测量技术能够为学生个性化学习提供帮助,有助于做到因材施教。目前我国已开展基于CD-CAT教育辅助系统的开发和使用,但与其他国家和地区相比较仍有差距。扩大教育测量专业人员队伍,加强CD-CAT在理论上的创新研究、在实践上的应用,开发更加适合个人、更加开放灵活的智能学习系统是我国教育测量的未来发展方向。     

2PLM下CAT选题策略比较

本文在两参数逻辑斯蒂克模型（2PLM）下,提出一种新的选题策略——平均测验难度匹配法（Avt—b）,并对四种选题策略下EAP能力估计趋势进行比较研究。通过模拟研究显示,Avt—b方法在CAT前期能够较快地锁定能力范围,较准确地作出能力估计。本文对CAT测试阶段的能力误差范围进行确定,对于多级评分模型的CAT选题策略开发具有一定的借鉴意义。