测验等值研究综述

本研究从研究历史、概念界定、数据收集设计、等值模型和等值方法、等值误差及不同等值方法的评价标准等五个方面对测验等值研究进行了文献综述,以期为今后等值研究的进一步开展提供理论基础。     

Accessibility,easiness and standards

In setting the cut-scores on National Curriculum tests it is important to maintain standards. In the process of test development, both within and across years, changes are made to the style of the questions in order to increase their ‘accessibility’. This raises the question of whether a more accessible test should have higher cut-scores. Purely statistical definitions of equating are blind to differences between ‘accessibility’ and ‘easiness’ and cut-scores derived from statistical equating methods will be higher for a more accessible test. Arguments about the increased validity of the more accessible test are sometimes used to justify not raising the cut-scores as much as would be indicated by statistical methods. These arguments are shown to be equivalent to postulating that changing the accessibility is changing the construct measured by the test. Using a statistical measurement model can provide a rational basis for understanding accessibility and identifying types of question where accessibility issues are causing a measurement problem.     

锚测验难度参数方差特征对测验等值的影响研究

本文使用R-2.15.2软件模拟研究锚测验难度参数方差特征对测验等值误差的影响,采用三种等值方法(链百分位等值法、Levine等值法和Tucker等值法)对锚测验不同类型的难度方差进行比较研究。结果显示,当锚测验难度方差小于全测验难度方差时,其等值的随机误差和系统误差与锚测验难度方差和全测验难度方差一致时(即锚测验为全测验的平行缩减版minitest时)的表现基本相同。因此,对锚测验而言,要求其与全测验具有相同的统计规格可能过于严格。