Robust estimation procedures and visual display techniques for a two-way classification model

An important problem in statistics is to study the effect of one or two factors on a dependent variable. This type of problem can be formulated as a regression problem (by using dummy (0,1) variables to represent the levels of factors) and the standard least squares (LS) analysis is well-known. The least absolute value (LAV) analysis is less well known, but certainly is becoming more widely used, especially in exploratory data analysis.The purpose of this report is to present a didactic treatment of visual display methods useful in exploratory data analysis. These visual display techniques (stem- and- leaf, box- and- whisker, and two-way plots) are presented for both the least squares and the least absolute value analyses of a two-way classification model.     

Comparisons of Bayesian estimation procedures for two-way contingency tables without interaction

Bayesian and empirical Bayesian estimation methods are reviewed and proposed for the row and column parameters in two-way Contingency tables without interaction. Rasch's multiplicative Poisson model for misreadings is discussed in an example. The case is treated where assumptions of exchangeability are reasonable a priori for the unknown parameters. Two different types of prior distributions are compared, It appears that gamma priors yield more tractable results than lognormal priors.     

Pooling: An experimental study of alternative testing and estimation procedures in a two-way error component model

This paper considers a two-way error component model with no lagged dependent variable and investigates the performance of various testing and estimation procedures applied to this model by means of Monte Carlo experiments. The following results were found: (1) The Chow-test performed poorly in testing the stability of cross-section regressions over time and in testing the stability of time-series regression across regions. (2) The Roy-Zellner test performed well and is recommended for testing the poolability of the data. (3) The Hausman specification test, employed to test the orthogonality assumption, gave a low frequency of Type I errors. (4) The Lagrange multiplier test, employed to test for zero variance components, did well except in cases where it was badly needed. (5) The problem of negative estimates of the variance components was found to be more serious in the two-way model than in the one-way model. However, replacing the negative variance estimates by zero did not have a serious effect on the performance of the second-round GLS estimates of the regression coefficients. (6) As in the one-way model, all the two-stage estimation methods performed reasonably well. (7) Better estimates of the variance components did not necessarily lead to better second-round GLS estimates of the regression coefficients.     

Model selection test procedures in a single linear equation of a dynamic simultaneous system and their defects in small samples

A variety of asymptotically valid tests for orthogonality, serial correlation, predictive failure, and of coefficient restrictions are presented, and their rejection probabilities are assessed in linear structural models with lagged dependent and (possibly) jointly dependent variables by Monte Carlo methods. For all test procedures the small-sample distribution under the null usually deviates substantially from the asymptotic distribution; this impedes their use in a reliable model selection strategy for econometric time-series analysis. Despite the harassing dependence of type I errors on factors generally unknown to the practitioner, inconsistencies originating from specification errors or from disregarded simultaneity may be detected by particular tests in particular situations. From this study some clues emerge on how to interpret (in)significant values of the various test statistics.     

枢纽内铁路客运站布局方案评价方法研究

为了评价枢纽内客运站的布局优劣和服务水平,进而优化规划方案,文章从枢纽的适应性、协调性、社会性以及经济性4个方面建立评价指标体系,然后用定量的方法给出各指标的定义及计算方法,再采用层次分析法与熵值法相结合的赋权方法确定指标的权重,从而得到布局方案的评价模型。     

Lifestyle as a generic concept in ethnographic research

In effect, one of the primary missions of ethnographic research is to explore the lifestyles of the people falling within its purview. Yet, rare indeed it is to find a study in the several disciplines presently conducting such research where this idea serves as the avowed focus of data collection. The concept of lifestyle is first reviewed, then defined with an eye to establishing a generic conception sufficient for guiding ethnographic exploration in a wide range of areas. Next, lifestyle is located theoretically with reference to the concepts of culture, status, status group, subculture, idioculture, everyday life, and social world. The many different types of lifestyles in modern life are then briefly examined. Finally, we consider certain methodological approaches thought to be especially appropriate for exploring lifestyles.     

Conceiving,designing and trailing a short‐form measure of job quality: a proof‐of‐concept study

The government has accepted the Taylor Review's recommendation that it should report annually on job quality in the UK. This article argues that three principles need to be followed in choosing the right measures and shows how these principles have been used to create a short job quality quiz ( www.howgoodismyjob.com ).     

A class of statistical models to weaken independence in two-way contingency tables

In this paper we study a new class of statistical models for contingency tables. We define this class of models through a subset of the binomial equations of the classical independence model. We prove that they are log-linear and we use some notions from Algebraic Statistics to compute their sufficient statistic and their parametric representation. Moreover, we show how to compute maximum likelihood estimates and to perform exact inference through the Diaconis-Sturmfels algorithm. Examples show that these models can be useful in a wide range of applications.     

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).     

“Distribution-free” estimates of efficiency in the U.S. banking industry and tests of the standard distributional assumptions

Studies of efficiency in banking and elsewhere often impose arbitrary assumptions on the distributions of efficiency and random error in order to separate one from the other. In this study, we impose much less structure on these distributions and only assume that efficiencies are stable over time while random error tends to average out. We are able to do so by estimating firm-specific effects on costs using panel data sets of over 28,000 observations on U.S. banks from 1980 to 1989. We find results similar to the literature—X-efficiencies or managerial differences in efficiency are important in banking, while scale-efficiency differences are not. However, we also find that the distributional assumptions usually imposed in the literature are not very consistent with these data.     

The concept of psychological capital: a comprehensive review

In this paper, we provide a comprehensive view on the concept of psychological capital (PsyCap) and develop an agenda for future research. PsyCap describes an individual’s psychological capacity that can be measured, developed, and managed for performance improvement. The higher-order construct comprises the psychological resources self-efficacy, hope, optimism, and resilience, and has been linked with a range of desirable work attitudes, behaviors, and other outcomes. By analyzing and structuring the existing literature on PsyCap, we identified several research gaps that require further analysis. In particular, we encourage researchers to expand the research on the effects of PsyCap to other workplace-related domains, especially the field of strategic decision-making, we call for researchers to further study the relationship between emotions and PsyCap, and we suggest to analyze the effects of PsyCap in the context of strategic human resources management. Also, future studies should establish transparency on the interaction between organizational change processes and PsyCap as well as the relative importance of the four components of PsyCap. We close by discussing the implications of our findings for corporate practice, such as employee selection and development.     

Employee development,commitment and intention to turnover: a test of ‘employability’ policies in action

Participation in three types of development activities is examined among salaried employees of a firm that significantly increased access to development after a series of layoffs in the late 1990s. Analyses of survey and archival data representing 667 employees show that on‐the‐job training was positively related to organisational commitment and negatively related to intention to turnover. Participation in tuition‐reimbursement, which provides more general or marketable skills, was positively related to intention to turnover. However, intention to turnover was reduced after earning a degree through tuition‐reimbursement if employees were subsequently promoted. Implications for an employment relationship based on ‘employability’ are discussed.     

Shaping buyer–supplier relationships in manufacturing contexts: Design and test of a contingency model

Although the idea that buyer–supplier partnerships can yield considerable benefits to firms is largely diffused among researchers and practitioners, the approach adopted in this paper is that no “one best way” exists in buyer–supplier relationships, but rather a “best way” for each specific exchange context. Hence, this paper proposes a contingency model for shaping and managing buyer–supplier relationships in manufacturing contexts. In order to test the model, an empirical study was performed on a sample of 45 buyer–supplier relationships within the Italian white goods industry. A three-dimensional performance indicator was computed to compare supplier performance achieved within relations matching the model's suggestions with those set differently. The results strongly suggest that suppliers involved in relationships set accordingly to the contingency model are likely to enjoy superior performance.     

Test of a technique for planning medical procedures in preventive health examination programs

This paper reports on a retrospective test of a linear programming (LP) technique for planning of medical procedures in preventive health examination (PHE) programs. The technique itself has been published earlier; hence only a brief review is presented here. The test was, in essence, a comparison between a PHE program run along conventional lines (all procedures to all patients) and a PHE program guided by the LP technique. The results showed that the LP technique has several advantages over the conventional mode of operation.     

Offshoring: Dimensions and diffusion of a new business concept

In order to leverage global cost differentials, companies are increasingly turning to offshoring. Nevertheless, discussions in research and practice on offshoring are characterized by the lack of a common definition as well as a theoretically grounded explanation for this phenomenon. This article presents an explicit definition in order to provide a stringent understanding of the term offshoring along the dimensions of contractual/legal arrangement and geographic location. Further, the driving forces of offshoring are analysed on the environmental and company levels. The article closes with a discussion of managerial implications and an outlook on aspects for further research.     

Revealed preference test and shortest path problem; graph theoretic structure of the rationalizability test

This paper presents some substantial relationships between the revealed preference test for a data set and the shortest path problem of a weighted graph. We give a unified perspective of several forms of rationalizability tests based on the shortest path problem and an additional graph theoretic structure, which we call the shortest path problem with weight adjustment. Furthermore, the proposed structure is used to extend the result of Quah (2014), which sharpened classical Afriat’s Theorem-type results.