Item-fit evaluation in biased tests: a study under Rasch model

In this paper, the power rates and distributional properties of the Outfit, Infit, Lz, ECI2z and ECI4z statistics when they are used in tests with biased or differential item functioning (DIF) were explored. In this study, different conditions of sample size, sample size ratio focal and reference group, impact between groups, DIF effect size, and percentage of DIF items were manipulated. In addition, examinee responses were generated to simulate uniform DIF. Results suggest that item fit statistics generally detected medium percents of DIF in large samples (1000/500 or 1000/1000) only when DIF effect size was relatively high and when the mean of focal and reference group was different. Moreover, when groups had equal mean, low correct identification rates were found in the five item-fit indices. In general, the results showed adequate control of false positive rates. These findings lead to the conclusion that all indices used in this study are partially adequate fit measures for detecting biased items, mainly when impact between groups is present and sample size is large.     

The Performance of Some Observed and Unobserved Conditional Invariance Techniques for the Detection of Differential Item Functioning

The current research investigates the performance of some conditional and unconditional invariance measures of differential item functioning (DIF), namely: the log-linear model, the logistic regression model, the signed and the unsigned area, the SOS1 and the SOS3. A simulation study is used to evaluate their ability to detect uniform as well as nondirectional nonuniform DIF under several test conditions. The factors that were subject to experimental manipulation in the simulation study are the size of the DIF, the ability distribution of the focal and the reference group, the sample size, the proportion of DIF items and the length of the test.     

Erroneous detection of nonuniform DIF using the Breslow-Day test in a short test

This paper studies the Type I error rate obtained using the Breslow-Day (BD) test to detect Nonuniform Differential Item Functioning (NUDIF) in a short test when the average ability of one group is significantly higher than that of the other. The performance is compared with the logistic regression (LR) and the standard Mantel-Haenszel procedure (MH). Responses to a 20-item test were simulated without Differential Item Functioning (DIF) according to the three-parameter logistic model. The manipulated factors were sample size and item parameters. The design yielded 40 conditions that were replicated 50 times and the false positive rate at a 5% significance level obtained with the three methods was recorded for each condition. In most cases, BD performed better than LR and MH in terms of proneness to Type I error. With the BD test, the Type I error rate was similar to the nominal one when the item with the highest discrimination and difficulty parameters in the case of equally sized groups was excluded from the goodness-of-fit to the binomial distribution (number of false positives among the fifty replications of a Bernoulli variable with parameter equal to 0.05).     

A Comparison of χ2, RFA and IRT Based Procedures in the Detection of DIF

Bias research began at the end of the 1960s anddeveloped rapidly in the following decades for obvioussocial and political reasons, and due to the importantimpact that this issue has on the field ofpsychological and educational measurement. Since then,several methods have been proposed for the study anddetection of item bias or differential itemfunctioning (DIF). This paper presents a simulationstudy comparing the potential of some of these methodsfor detecting DIF: two IRT-based techniques (area measures), three ²-based procedures (MantelHaenszel, Logit Model and Logistic Regression) and theRestricted Factor Analysis method. The results showthat the technique that appears to do the best job isthe Mantel Haenszel statistic. Moreover, all detectiontechniques tend to overidentify DIF items, that is,some of the items labeled with DIF may in fact bewithout DIF. This tendency is slightly reversed in theLogistic Regression procedure.     

Influence of equal or unequal comparison group sample sizes on the detection of differential item functioning using the Mantel–Haenszel and logistic regression techniques

In recent decades several methods have been developed for detecting differential item functioning (DIF), and many studies have aimed to identify both the conditions under which items may or may not be adequate and the factors which affect their power and Type I error. This paper describes a Monte Carlo experiment that was carried out in order to analyse the effect of reference group sample size, focal group sample size and the interaction of the two on the power and Type I error of the Mantel–Haenszel (MH) and Logistic regression (LR) procedures. The data were generated using a three-parameter logistic model, the design was fully-crossed factorial with 12 experimental conditions arising from the crossing of the two main factors, and the dependent variables were power and the rate of false positives calculated across 100 replications. The results enabled the significant factors to be identified and the two statistics to be compared. Practical recommendations are made regarding use of the procedures by psychologists interested in the development and analysis of psychological tests.     

A Comparison of Techniques for Detecting Cross-Cultural Inequivalence at the Item Level

This paper uses a Monte Carlo study to compare some DIFdetection techniques with respect to their ability to detect uniform aswell as nonuniform item bias.The techniques that are used in the comparison are the loglinearmodel, the logistic regression model, the signed and the unsignedarea between the item characteristic curves, the SOS1 and theSOS3 measure. A first Monte Carlo study was set up to assess theempirical distributions of the unsigned area (in the 2-PLM), theSOS1 and the SOS3 measures. A second simulation study compares all these techniques with respect to their ability to detect DIF. It was alsoinvestigated whether using a two-stage approachyields better results.     

资源紧缺型城市的物流政策体系研究

在土地和资金紧缺的约束下,如何制定有效的物流政策以合理的配置资源成为资源紧缺型城市发展经济的首要问题。文中以汕头现代物流业发展为例,在分析比较了上海、广州、深圳、厦门等城市的物流战略目标和政策体系的基础上,从物流产业政策、物流管理协调机制、基础设施和信息平台保障政策等方面提出了汕头市的现代物流政策体系。     

Application of Shrinkage Techniques in Logistic Regression Analysis: A Case Study

Logistic regression analysis may well be used to develop a predictive model for a dichotomous medical outcome, such as short-term mortality. When the data set is small compared to the number of covariables studied, shrinkage techniques may improve predictions. We compared the performance of three variants of shrinkage techniques: 1) a linear shrinkage factor, which shrinks all coefficients with the same factor; 2) penalized maximum likelihood (or ridge regression), where a penalty factor is added to the likelihood function such that coefficients are shrunk individually according to the variance of each covariable; 3) the Lasso, which shrinks some coefficients to zero by setting a constraint on the sum of the absolute values of the coefficients of standardized covariables.
Logistic regression models were constructed to predict 30-day mortality after acute myocardial infarction. Small data sets were created from a large randomized controlled trial, half of which provided independent validation data. We found that all three shrinkage techniques improved the calibration of predictions compared to the standard maximum likelihood estimates. This study illustrates that shrinkage is a valuable tool to overcome some of the problems of overfitting in medical data.     

物流系统的数学模型

作为企业“第三利润源泉”的物流,对其成本的控制目前已经成为物流合理化进程中的热点问题。文章把物流系统看成是一个特殊的生产系统,用柯布一道格拉斯生产函数方程对其进行建模。把物流系统的产出——满足服务需求看成是此方程的产出,把运输费用、储存费用和管理费用看戍是投入．对物流系统的数学建模提供了一个新的方法。最后用这个物流系统模型对社会物流系统进行了实例验证。     

基于Logistic模型的我国房地产开发投资压力测试研究

对我国房地产开发投资风险进行压力测试分析,考虑房地产开发投资的地域性差异,选取三个代表地区——上海、辽宁和贵州,首先分析影响房地产投资的风险因素,然后运用Logistic回归模型建立该地区的房地产投资风险评价模型,确定重要影响因素,设定"异常"情景,最后测试房地产业的抗压能力。研究发现:影响三个地区房地产投资的因素不同,且重要性不一致。房地产销售价格变动与上海房地产投资风险关系最为密切,居民消费价格指数波动对辽宁房地产投资影响最大,而房地产投资的波动直接影响贵州房地产业的健康运行。对这三个重要指标设定极端情景,三个地区的房地产投资风险出现了不同程度的提高,由此得出,在投资这三个地区或与其相似类型的地区时,要充分考虑实际的宏观经济情况,特别是显著指标的变动情况,使投资更加的合理和安全。     

中小上市公司治理结构与会计信息透明度关系研究

完善的公司治理结构对会计信息披露有着积极的作用,会计信息披露亦有助于提高公司治理和经营管理透明度。经对2007-2010年深市样本中小上市公司Logistic回归分析,结果表明:第一大股东控制力、董事会规模和公司规模与会计信息透明度正相关;独立董事比例、董事长与总经理两职合一和资产负债率与会计信息透明度负相关;监事会规模与会计信息透明度无明显的相关性。     

基于城乡统筹的宁波农村物流网络体系建设运作模式探索

近年来,随着宁波农村经济快速发展,农村物流流通基础设施的薄弱,流通领域的投资、物流结点的建设缺乏科学规划等特点与农村经济发展之间的矛盾日益突出。为解决这一矛盾,文中基于城乡统筹的观点,运用定性分析的方法,研究现阶段宁波农村物流网络建设现状,发现物流网络建设过程中存在的问题。从而探索性地提出五种宁波农村物流网络体系建设的运作模式。     

Consistency vs Flexibility: The Impact of Employee Voice in Rule-Based and Discretionary Decision Procedures

Consistency and flexibility are desirable, but incompatible, features of decision-making procedures. A comparison of a rule-based decision procedure (maximizing consistency) with a discretionary decision procedure (maximizing flexibility) was conducted. Employee voice was predicted to interact with decision procedure in impacting fairness perceptions. Student participants (N = 128) in a 2 × 2 laboratory simulation viewed videotaped depictions of a supervisor discussing a positive drug test result with an employee. The employee was given, or not given, an opportunity to explain; the supervisor was permitted discretion in determining the consequence or was completely bound by company policy. The proposed advantages of each decision procedure were obtained under contrasting levels of employee voice. Voice was desirable when the supervisor had discretionary authority; voice was unnecessary or even detrimental when a rule-based procedure was used. No overall preference between these two decision procedures was evident.     

浅谈我军物流人才的培养

随着新时期军事斗争任务的进一步加剧,培养一支高素质、专业化的军事物流人才队伍已成为当前军事物流发展和建设中的重要任务。     

Logistic Regression, a review

A review is given of the development of logistic regression as a multi-purpose statistical tool.
A historical introduction shows several lines culminating in the unifying paper of Cox (1966), in which theory as developed in the field of bio-assay is shown to be applicable to designs as discriminant-analysis and case-control study. A review is given of several designs all leading to the same analysis. The link is made with epidemiological literature.
Several optimization criteria are discussed that can be used in the case of more observations per cell, namely maximum likelihood, minimum chi-square and weighted regression on the observed logits. Recent literature on the goodness of fit problem is reviewed and finally, comments are made about the non-parametric approach to logistic regression which is still in rapid development.     

A new approach for detecting shifts in forecast accuracy

Forecasts play a critical role at inflation-targeting central banks, such as the Bank of England. Breaks in the forecast performance of a model can potentially incur important policy costs. However, commonly-used statistical procedures implicitly place a lot of weight on type I errors (or false positives), which results in a relatively low power of the tests to identify forecast breakdowns in small samples. We develop a procedure which aims to capture the policy cost of missing a break. We use data-based rules to find the test size that optimally trades off the costs associated with false positives with those that can result from a break going undetected for too long. In so doing, we also explicitly study forecast errors as a multivariate system. The covariance between forecast errors for different series, although often overlooked in the forecasting literature, not only enables us to consider testing in a multivariate setting, but also increases the test power. As a result, we can tailor our choice of the critical values for each series not only to the in-sample properties of each series, but also to the way in which the series of forecast errors covary.     

逻辑产品功能-成本分析初探

价值工程(ValueEngineering,VE)的核心之一是产品的功能成本分析。传统VE的功能成本分析是针对物理产品的,物理产品的功能以零部件为载体,为寻找零部件的替代品,需要建立零部件成本和功能分摊矩阵。而逻辑产品没有载体,本文在分析逻辑产品特点的基础上,研究其功能成本分析问题。     

我国物流园区建设发展现状及存在问题的分析

物流园区（Logistic park)是指由分布相对集中的多个物流组织设施和不同的专业化物流企业所构成，具有产业组织、经济运行等功能规模化的物流组织区域，我国现代物流发展迅速，尤其是在物流园区的规划与建设方面，取得相当可观的进展和不少有益的经验。本文简要分析近年来我园各地区物流园区规划建设发展状况，并对在这一发展过程中不同程度存在的各种问题进行了分析。     

Multivariate residual‐based finite‐sample tests for serial dependence and ARCH effects with applications to asset pricing models

In this paper, we propose several finite‐sample specification tests for multivariate linear regressions (MLR). We focus on tests for serial dependence and ARCH effects with possibly non‐Gaussian errors. The tests are based on properly standardized multivariate residuals to ensure invariance to error covariances. The procedures proposed provide: (i) exact variants of standard multivariate portmanteau tests for serial correlation as well as ARCH effects, and (ii) exact versions of the diagnostics presented by Shanken ( 1990 ) which are based on combining univariate specification tests. Specifically, we combine tests across equations using a Monte Carlo (MC) test method so that Bonferroni‐type bounds can be avoided. The procedures considered are evaluated in a simulation experiment: the latter shows that standard asymptotic procedures suffer from serious size problems, while the MC tests suggested display excellent size and power properties, even when the sample size is small relative to the number of equations, with normal or Student‐t errors. The tests proposed are applied to the Fama–French three‐factor model. Our findings suggest that the i.i.d. error assumption provides an acceptable working framework once we allow for non‐Gaussian errors within 5‐year sub‐periods, whereas temporal instabilities clearly plague the full‐sample dataset. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluations of Drug-Testing Programs

In three experiments undergraduate students at an urban university evaluated drug-testing programs described in scenarios. Evaluations were inversely related to the false positive rate and were more favorable when a positive test result led to rehabilitation than when it led to termination of employment. Inconsistent effects on evaluations were observed for ability of the test to distinguish between previous drug use and current drug-based impairment, false negative rate, and implications of drug-impaired performance for public safety. There was also mixed evidence concerning the relation between evaluations and respondent belief in a just world. These results provide some support for Crant and Bateman's (1989) justice-based model of reactions to drug-testing and have implications for organizational drug-testing policies.