Examining differential item functioning due to item difficulty and alternative attractiveness

A method for analyzing test item responses is proposed to examine differential item functioning (DIF) in multiple-choice items through a combination of the usual notion of DIF, for correct/incorrect responses and information about DIF contained in each of the alternatives. The proposed method uses incomplete latent class models to examine whether DIF is caused by the attractiveness of the alternatives, difficulty of the item, or both. DIF with respect to either known or unknown subgroups can be tested by a likelihood ratio test that is asymptotically distributed as a chi-square random variable.     

Robust estimation of ability in the Rasch model

Estimating ability parameters in latent trait models in general, and in the Rasch model in particular is almost always hampered by noise in the data. This noise can be caused by guessing, inattention to easy questions, and other factors which are unrelated to ability. In this study several alternative formulations which attempt to deal with these problems without a reparameterization are tested through a Monte Carlo simulation. It was found that although no one of the tested schemes is uniformly superior to all others, a modified jackknife stood out as the best one in general, it was also super efficient (more efficient than the asymptotically optimal estimator) for tests with forty or fewer items. It is proposed that this sort of jackknifing scheme for estimating ability be considered for practical work.This research was funded through a grant from the Law Enforcement Assistance Administration (78-NI-AX-0047) to the Bureau of Social Science Research, Howard Wainer, Principal Investigator. We would like to thank Ronald Mead, Anne Morgan and James Ramsay for kind, generous, and invaluable help at various stages of the project.     

Maximum likelihood estimation of the joint covariance matrix for sections of tests given to distinct samples with application to test equating

Consider an old testX consisting ofs sections and two new testsY andZ similar toX consisting ofp andq sections respectively. All subjects are given testX plus two variable sections from either testY orZ. Different pairings of variable sections are given to each subsample of subjects. We present a method of estimating the covariance matrix of the combined test (X ₁, ...,X _s ,Y ₁, ...,Y _p ,Z ₁, ...,Z _q ) and describe an application of these estimation techniques to linear, observed-score, test equating.The author is indebted to Paul W. Holland and Donald B. Rubin for their encouragement and many helpful comments and suggestions that contributed significantly to the development of this paper.This research was supported by the Program Statistics Research Project of the ETS Research Statistics Group.     

On Herrnstein's equation and related forms

In 1970, Herrnstein proposed a simple equation to describe the relation between response and reinforcement rates on interval schedules. Its empirical basis is firm, but its theoretical foundation is still uncertain. Two approaches to the derivation of Herrnstein's equation are discussed. It can be derived as the equilibrium solution to a process model equivalent to familiar linear-operator learning models. Modifications of this approach yield competing power-function formulations. The equation can also be derived from the assumption that response strength is proportional to reinforcement rate, given that there is a ceiling on response rate. The proportional relation can, in turn, be derived from a threshold assumption equivalent to Shimp's “momentary maximizing”. This derivation implies that the two parameters of Herrnstein's equation should be correlated, and may explain its special utility in application to internal schedules.     

时间信息加工与信息加工时间特性双视角下的重要时间参数及其证据

时间既是人类信息加工的对象, 也是(非时间)信息加工的制约因素。数十毫秒至数秒之间的时间加工与人类日常生活关联紧密, 譬如主观计时、演奏及言语等活动。根据以往文献分析可知, 在该时间区域内, 20~ 60 ms、1/3~1 s、2~3 s是研究者关注的重要时间参数, 但是支持这些参数的证据尚存分歧。首先从“时间信息加工”和“信息加工的时间特性”的视角介绍时间参数的基本观点及其提出背景, 然后基于“时间信息加工”视角从行为学研究、脑损伤研究、神经药理学研究, 脑电研究、脑成像研究、经颅磁刺激研究、经颅直流电刺激研究等领域介评了1/3~1 s和2~3 s分界区域的证据, 接着基于“信息加工的时间特性”视角从时序知觉阈限研究、感觉运动同步研究、主观节奏研究、言语行为研究、知觉逆转研究、返回抑制研究及失匹配负波研究等领域介评了20~60 ms和2~3 s时间窗口的证据。未来研究既要注意构建基于分界区域与时间窗口的更强解释力的理论假说, 也要厘清分界区域与时间窗口的联系与区别。     

Parameters of Time-out: Research Update and Comparison to Parenting Programs,Books, and Online Recommendations

In reviews published more than 30 years ago, eight parameters important to the use of time-out were identified and available research was summarized. The purpose of the current paper is to provide an updated summary of existing research for each parameter of time-out. Within each parameter, we conducted a thorough review of the published literature and identified all peer-reviewed articles addressing each parameter. We identified and summarized a total of 46 articles across the eight parameters, including 32 not cited in previous reviews. Sufficient findings were available to draw conclusions regarding time-out warning, schedule of time-out, contingent versus noncontingent release, and duration. Tentative conclusions based on only a few studies could be drawn in regard to instructional versus physical administration and verbalized reason for time-out. No conclusions could be drawn regarding time-out signal and specific time-out location. While we know much more today regarding effective implementation of time-out, there is a clear need for further exploration within these identified parameters. In addition to summarizing the literature, we reviewed recommendations made by behavioral parent training programs, parenting books, and parenting Web sites, and compared how well their recommendations matched current research based on the conclusions drawn from our review. We found that parenting sources made strong and specific recommendations on several of the parameters that were either not consistent with available research or simply lacked a sufficient research base.     

Why We Walk the Way We Do

By using inverse dynamics and forceplate recordings, this study established the principle of oscillating systems and the influence of gravity and body parameters on the programming of the gait parameters, step frequency and length. Calculation of the ratio of the amplitude of the center of mass (CM) and the center of foot pressure (CP) oscillations yielded an equation and established a biomechanical constant, the natural body frequency (NBF). NBF appears to be an absolute invariant parameter, specific to human standing posture and gait in terrestrial gravity, which influences the relative positions of CM and CP and whose value separates the frequency bands of standing posture from those for gait. This equation was tested by using the experimental paradigm of stepping in place and then used in calculating the magnitude of CM oscillations during gait. The biomechanical analysis of the experimental observations allows one to establish the relationships between body parameters and gravity and the central programming of locomotor parameters.     

Evaluating the Impact of Careless Responding on Aggregated-Scores: To Filter Unmotivated Examinees or Not?

When examinees' test-taking motivation is questionable, practitioners must determine whether careless responding is of practical concern and if so, decide on the best approach to filter such responses. As there has been insufficient research on these topics, the objectives of this study were to: a) evaluate the degree of underestimation in the true mean when careless responses are present, and b) compare the effectiveness of two filtering procedures in purifying biased aggregated-scores. Results demonstrated that: a) the true mean was underestimated by around 0.20 SDs if the total amount of careless responses exceeded 6.25%, 12.5%, and 12.5% for easy, moderately difficult, and difficult tests, respectively, and b) listwise deleting data from unmotivated examinees artificially inflated the true mean by as much as .42 SDs when ability was related to careless responding. Findings from this study have implications for when and how practitioners should handle careless responses for group-based low-stakes assessments.     

四参数模型对被试作答异常现象的拟合与纠正

心理与教育测验中存在着被试作答异常现象(能力测验中的猜测现象和睡眠现象, 人格测验中的非0下渐近线现象和非1上渐近线现象), 会导致被试能力或人格特征的测量偏差。在能力测验中, 研究者已提出了多种方法来纠正猜测现象和睡眠现象, 这些方法往往需要调整或删除被试作答信息, 而四参数模型不需要改变被试作答信息而能有效纠正被试能力高估或低估现象。在人格测验中存在着非0下渐近线和非1上渐近线现象, 四参数模型能增强测验项目拟合性能, 提高人格测验的准确性。     

群体水平IRT模型及其应用——兼与IRT的比较

传统上,群体评估都是以个体的评估结果的平均值为基础进行的。而群体水平IRT理论则可以避开对个体的评估,直接实现对群体的评估,它具有许多传统方法难以企及的优点。本文将群体水平IRT模型应用于2007年某省高考英语阅读理解的410所学校的能力评估,评估结果发现：410所学校的英语阅读理解能力几乎都在[-1,1]区间内,没有能力极高或极低的学校。对这些学校而言,测验中所有项目的难度较易,区分度适中。所有的评估结果与IRT模型的评估结果在 的水平上相关显著,表明GIRT模型在实践中是可以选择的一种群体评估方法。