认知诊断计算机化自适应测验的选题策略

随着认知诊断计算机化自适应测验(cognitive diagnostic computerized adaptive testing, CD-CAT)理论与实践的发展, 兼顾知识状态与能力的双目标CD-CAT逐渐受到重视。选题策略是CAT的核心, 通过梳理传统CD-CAT和双目标CD-CAT选题策略的研究, 并对它们的特点、关系及表现进行介绍和评析。最后, 基于认知诊断模型与CAT实践发展指出未来应加强一般化认知模型、复杂测验条件认知诊断模型下选题策略的研究; 应开发双目标诊断测验的项目和测验特征指标; 还应加强非参数选题方法和CD-CAT的实践应用研究。     

认知诊断CAT选题策略及初始题选取方法

计算机化认知诊断自适应测验(CD_CAT)是将认知诊断的基本理论、方法与计算机化自适应测验相结合的产物,是现代测量学发展的新领域。对于计算机化自适应测验（CAT）中的选题策略研究一直是国内外学者关注的问题,然而对于计算机化认知诊断自适应测验的选题策略研究却很少报导,而对于计算机化认知诊断自适应测验的初始题选取方法的研究却更少。本研究采用计算机模拟程序对HO-DINA模型下CD_CAT的五种选题策略及二种初始题选取方法进行研究。研究表明：不同初始题选取方法及选题策略均会影响对被试诊断的准确性及能力估计的精度;总体来看,对于二种初始题选取方法,本研究提出的“T阵法”优于传统的随机法;对于五种选题策略,SL_GDI法最优;初始题选取方法及选题策略的搭配中,“T阵法”和SL_GDI法的搭配最佳。     

CAT选题策略分类概述

选题是计算机化自适应测验（CAT）测试过程的关键环节,选题策略的目标是要达到较高的测量精度,同时也实现试题曝光率控制及其他测验目标的实现.本文根据选题策略的基本原理和衍生发展,将众多CAT选题策略分为五大选题策略系列：Fisher函数系列、K-LI函数系列、α分层系列、贝叶斯系列、b匹配系列;并根据测验目标（测验精度、试题曝光率控制、内容平衡、多条件约束）对这些选题策略进行了细分,并对CAT选题策略的选择思路进行归纳.     

认知诊断计算机化自适应测验的题库使用均匀性初探

项目曝光控制是认知诊断计算机化自适应测验(CD-CAT)中亟需解决的重要问题之一。采用蒙特卡洛模拟方法对CD-CAT中五种常用选题策略(随机化方法、KL信息量方法、香农熵方法、后验加权的KL信息量方法和综合后验加权和距离加权的KL信息量方法)的题库使用情况进行探讨。结果发现:四种非随机化选题策略的题库使用均匀性较差、测验重叠率高,从而导致测验安全性较差;香农熵方法的判准率总是最高。今后可以将传统CAT中的项目曝光控制技术融入到CD-CAT选题策略中。     

计算机化自适应测验在认知诊断中的应用

作为认知诊断与计算机化自适应测验相结合的产物, 认知诊断计算机化自适应测验(Cognitive Diagnostic Computerized Adaptive Testing, CD-CAT)是对被试知识状态的自适应。它既有传统CAT所面临的普遍性问题, 也有在认知诊断中遇到的特殊问题：由于认知诊断中涉及属性这一概念, CD-CAT与传统CAT有很大的差别。本文紧紧围绕属性引起的差异, 分别从认知诊断模型、题库建设、起始规则、选题策略、被试知识状态估计和终止规则等几部分详细介绍CD-CAT的研究进展和存在的问题。     

计算机自适应性测验(CAT)选题策略的新进展

在计算机自适应性测验(CAT)中,传统的项目选题策略正面对越来越多的问题,比如:测验的安全,项目的曝光率,项目的平衡应用等等。分层选题策略的新发展-A-STR和BAS-选题策略部分地解决了传统的选题策略所面临的难题。能够有效地控制高区分度项目的曝光率,增加低区分度项目的曝光率,平衡项目的应用,提高测验效率,降低测验成本等等。为计算机自适应测验的选题策略提供了一种更加有效的方法,也为我国开展计算机自适应测验提供了一种思路。     

具有认知诊断功能的计算机化自适应测验的研究与实现

构造具有认知诊断功能的计算机化自适应测验（Computerized Adaptive Testing,CAT）,关键在于设计不同于传统CAT的选题策略。本文采用先认知诊断后估计能力的方法,在诊断阶段用状态转换图描述特定认知领域中所有知识状态及这些状态之间的联系,以图的深度优先算法为基础设计选题策略;而在能力估计精细化阶段,每个被试所测项目,不仅与其能力估计值相匹配,且只与其所掌握的属性相关。本文采用蒙特卡罗模拟针对三种不同的属性结构进行试验,结果良好     

认知诊断CAT中项目曝光控制方法的比较

项目曝光率关系到题库建设和测验安全,是计算机化自适应测验(Computerized Adaptive Testing, CAT)需要考虑的重要问题。在认知诊断 CAT 情形下,首先基于传统 CAT 中 a-分层方法的思想提出按项目信息量对题库分层的分层多阶段(Stratified Multistage, SM)选题方法;然后将 SM 方法与项目合格(Item Eligibility, IE)方法相结合得到SMIE方法。在此基础上,开展模拟研究比较SM、IE、SMIE、最大修正优先指标(Maximum Modified Priority Index, MMPI)方法、限制阈值(Restrictive Threshold, RT)方法和限制进度(Restrictive Progressive, RPG)方法的选题表现。总体上,它们的测量精度从高到低依次为IE、SM、SMIE、RT、RPG和MMPI方法;项目曝光分布均匀性的优劣次序为MMPI、RPG、SMIE、RT、SM和IE方法;SMIE和RT方法能较好地平衡测量精度和项目曝光均匀性要求。     

可修改答案的计算机化自适应测验的方法

与传统的纸笔测验(Paper And Pencil Based Test, P&P)相比计算机化自适应测验(Computerized Adaptive Testing, CAT)根据被试的作答反应自适应地选择题目, 它不仅缩短了测验长度, 还极大地提高了测验的准确性。然而, 目前绝大多数CAT不允许被试修改答案, 研究者主要担心修改答案会降低CAT的有效性。允许修改答案符合被试一贯的测验习惯, 修改之后的分数更能反映被试真实的水平, 从而能够进一步促进CAT在实际中的应用。现有的研究主要从三个方面提出了可修改答案CAT的控制方法：一是测验设计; 二是改进选题策略; 三是建构模型。未来的研究应进一步探讨这些方法之间的比较与结合, 以及对可修改答案认知诊断CAT (Cognitive Diagnostic CAT, CD-CAT)的研究。     

具有认知诊断功能的多阶段自适应测验及其影响因素研究

MST结合了纸笔测验和CAT的优势,现阶段在美国的许多大型考试中得到了应用。本文结合MST、认知诊断、CD-CAT和OMST的思想对CD-MST的可行性进行研究。CD-MST具有认知诊断和自适应的功能,能够使用较少的题目为被试提供即时的、准确的、丰富的诊断信息;同时它计算速度较快,允许考生返回检查和修改,更符合实际考试情境,且在测验的编制上更容易控制。本研究考察了选题策略和题库质量对不同测验设计的CD-MST的影响,并同CD-CAT进行了比较。通过模拟研究发现：MPWKL、GDI和SHE选题策略同样也适用于CD-MST的选题,在题库质量好的情况下这三种选题策略的判准率同CD-CAT持平。CD-MST的测验时间要比CD-CAT缩短2/3以上。     

认知诊断CAT中具有非统计约束选题方法的比较

项目曝光控制和内容约束关系到测验安全、测验的信度和效度, 是计算机化自适应测验(Computerized Adaptive Testing, CAT)中两类重要的非统计约束条件。本文在认知诊断CAT中针对内容约束和项目曝光控制要求, 运用5种方法选择测验项目。它们分别是：(1) Monte Carlo方法与项目合格方法相结合, 记为MC-IE; (2) Monte Carlo方法与最大优先指标方法相结合, 记为MC-MPI; (3) Monte Carlo方法与限制阈值方法相结合, 记为MC-RT; (4) Monte Carlo方法与限制进度指标方法相结合, 记为MC-RPG以及(5) Monte Carlo方法与最大后验概率方法相结合, 记为MC-PP。然后通过在线性、收敛、发散、无结构和独立五种属性结构下构建题库并运用重参化融融统和模型模拟被试反应比较它们的选题表现。研究发现, (1) 相同选题方法在不同属性结构下项目曝光率的分布类似, 测量精度按线性、收敛、发散、无结构和独立结构的顺序依次降低; (2) 相同属性结构下, 不同方法的测量精度高低依次为MC-PP、MC-IE、MC-RT、MC-MPI和MC-RPG方法; 项目曝光均匀性优劣依次为MC-RPG、MC-MPI、MC-RT、MC-IE和MC-PP方法。统一量纲值表明, MC-RPG方法的综合表现最好, MC-MPI方法的表现次之。     

Online Calibration Via Variable Length Computerized Adaptive Testing

Item calibration is an essential issue in modern item response theory based psychological or educational testing. Due to the popularity of computerized adaptive testing, methods to efficiently calibrate new items have become more important than that in the time when paper and pencil test administration is the norm. There are many calibration processes being proposed and discussed from both theoretical and practical perspectives. Among them, the online calibration may be one of the most cost effective processes. In this paper, under a variable length computerized adaptive testing scenario, we integrate the methods of adaptive design, sequential estimation, and measurement error models to solve online item calibration problems. The proposed sequential estimate of item parameters is shown to be strongly consistent and asymptotically normally distributed with a prechosen accuracy. Numerical results show that the proposed method is very promising in terms of both estimation accuracy and efficiency. The results of using calibrated items to estimate the latent trait levels are also reported.     

Computerized adaptive personality assessment: an illustration with the Absorption scale

This article introduces the theory behind and applications of adaptive personality assessment based on the item response theory. Two adaptive testing strategies were compared: (a) fixed test length and (b) clinical decision. Real-data simulations, based on the item responses from 1,000 subjects who had previously taken the 34-item Absorption scale (Tellegen, 1982) by means of paper-and-pencil format, were used to illustrate these strategies. Results suggest that computerized adaptive personality assessment works impressively well. With the fixed-test-length strategy, a 50% savings in administered items was achieved with little loss of measurement precision. In the clinical-decision testing strategy, individuals who were extreme on the Absorption trait were identified with perfect accuracy using, on average, 25% of the available items. The implications of these results for personality research and assessment are discussed.     

Design and implementation of a microcomputer-based adaptive testing system

Adaptive testing is a relatively new form of test administration in which a test is tailored to the individual taking it by choosing items most informative about that person. Methods for determining which items are most appropriate take on a variety of forms, some requiring extensive computation, and almost all requiring administration by a computer. The increasing availability of inexpensive microcomputer systems has made adaptive testing possible when access to larger computer systems is impractical. To make implementation of a variety of adaptive testing methods feasible on a microcomputer, a system efficient from both the examinee’s and the test constructor’s perspectives is necessary. This paper begins by briefly outlining the strategies of adaptive testing developed to date and showing how, structurally, they can be grouped into three general categories. Considerations in design of a test-specification subsystem are then discussed as they relate to this categorization. Finally, a specific implementation of a subsystem for use under the CP/M microcomputer operating system is described. Techniques used to make the extensive computations required by adaptive testing feasible on a microcomputer are presented.     

On initial item selection in cognitive diagnostic computerized adaptive testing

There has recently been much interest in computerized adaptive testing (CAT) for cognitive diagnosis. While there exist various item selection criteria and different asymptotically optimal designs, these are mostly constructed based on the asymptotic theory assuming the test length goes to infinity. In practice, with limited test lengths, the desired asymptotic optimality may not always apply, and there are few studies in the literature concerning the optimal design of finite items. Related questions, such as how many items we need in order to be able to identify the attribute pattern of an examinee and what types of initial items provide the optimal classification results, are still open. This paper aims to answer these questions by providing non‐asymptotic theory of the optimal selection of initial items in cognitive diagnostic CAT. In particular, for the optimal design, we provide necessary and sufficient conditions for the Q ‐matrix structure of the initial items. The theoretical development is suitable for a general family of cognitive diagnostic models. The results not only provide a guideline for the design of optimal item selection procedures, but also may be applied to guide item bank construction.     

Look-ahead content balancing method in variable-length computerized classification testing

Content balancing is one of the most important issues in computerized classification testing. To adapt to variable-length forms, special treatments are needed to successfully control content constraints without knowledge of test length during the test. To this end, we propose the notions of ‘look-ahead’ and ‘step size’ to adaptively control content constraints in each item selection step. The step size gives a prediction of the number of items to be selected at the current stage, that is, how far we will look ahead. Two look-ahead content balancing (LA-CB) methods, one with a constant step size and another with an adaptive step size, are proposed as feasible solutions to balancing content areas in variable-length computerized classification testing. The proposed LA-CB methods are compared with conventional item selection methods in variable-length tests and are examined with different classification methods. Simulation results show that, integrated with heuristic item selection methods, the proposed LA-CB methods result in fewer constraint violations and can maintain higher classification accuracy. In addition, the LA-CB method with an adaptive step size outperforms that with a constant step size in content management. Furthermore, the LA-CB methods generate higher test efficiency while using the sequential probability ratio test classification method.