Sensitivity and Stability Analysis in DEA: Some Recent Developments

This papersurveys recently developed analytical methods for studying thesensitivity of DEA results to variations in the data. The focusis on the stability of classification of DMUs (Decision MakingUnits) into efficient and inefficient performers. Early workon this topic concentrated on developing solution methods andalgorithms for conducting such analyses after it was noted thatstandard approaches for conducting sensitivity analyses in linearprogramming could not be used in DEA. However, some of the recentwork we cover has bypassed the need for such algorithms. Evolvingfrom early work that was confined to studying data variationsin only one input or output for only one DMU at a time, the newermethods described in this paper make it possible to determineranges within which all data may be varied for any DMU beforea reclassification from efficient to inefficient status (or vice versa) occurs. Other coverage involves recent extensionswhich include methods for determining ranges of data variationthat can be allowed when all data are varied simultaneously for all DMUs. An initial section delimits the topics to be covered.A final section suggests topics for further research.     

Some Recent Developments in Futures Hedging

The use of futures contracts as a hedging instrument has been the focus of much research. At the theoretical level, an optimal hedge strategy is traditionally based on the expected–utility maximization paradigm. A simplification of this paradigm leads to the minimum–variance criterion. Although this paradigm is quite well accepted, alternative approaches have been sought. At the empirical level, research on futures hedging has benefited from the recent developments in the econometrics literature. Much research has been done on improving the estimation of the optimal hedge ratio. As more is known about the statistical properties of financial time series, more sophisticated estimation methods are proposed. In this survey we review some recent developments in futures hedging. We delineate the theoretical underpinning of various methods and discuss the econometric implementation of the methods.     

Recent Developments in Modelling Nonstationary Vector Autoregressions

In this paper we review some recent developments in the modelling of nonstationary vector autoregressions (VARs) which we feel have great potential for furthering applied researchers understanding of the relationships linking the variables making up a VAR. The developments surveyed are the use of model determination criteria in selecting lag length, trend order and cointegrating rank, causality testing in vector error correction models, FM-VAR estimation of levels VARS, common trends and cycles analysis, permanent and transitory decompositions, impulse response asymptotics, and the links between cointegrated VARs and structural models. The techniques are illustrated by applications to the modelling of U.K. equities, dividends and interest rates.     

Latent and Actual Entrepreneurship in Europe and the US: Some Recent Developments

This paper uses 2004 survey data from the 15 old EU member states and the US to explain country differences in latent and actual entrepreneurship. Other than demographic variables such as gender, age and education, the set of covariates includes the perception by respondents of administrative complexities, of availability of financial support and of risk tolerance as well as country-specific effects. A comparison is made with results using a similar survey in 2000. While a majority of the surveyed population identifies lack of financial support as an obstacle to starting a new business, the role of this variable in both latent and actual entrepreneurship appears to be even more counterintuitive in 2004 than in 2000: it has no impact on actual entrepreneurship and is positively related to latent entrepreneurship. Administrative complexities, also perceived as an obstacle by a large majority of the population, have the expected negative impact both for latent and actual entrepreneurship in both years. Country-specific effects are important both for latent and actual entrepreneurship and the comparison of 2000 and 2004 results suggests that, once all other factors are controlled for, an improvement in actual entrepreneurship in the EU relative to the US has taken place in the last four years. However, in terms of unweighted averages actual entrepreneurship remained about the same. Latent entrepreneurship dropped while this drop seems to have occurred evenly in the US and the EU member states.     

Political Macroeconomics: A Survey of Recent Developments

The paper surveys political macroeconomics, covering its development from Rogoff's conservative central banker to the most recent discussions of monetary policy and institutional design. Topics include the inflation-stabilization trade-off, central bank independence with escape clauses and overruling with costs, inflation targets, performance contracts for monetary authorities, and the consequences of output persistence for these issues. Further topics are the political business cycle when output is persistent, the political macroeconomics of fiscal policy, the government spending bias, and the game-theoretic interaction between fiscal and monetary policy. All work is discussed within a coherent analytical framework.     

Recent Developments of Statistical Approaches in Aspects of Accounting: a Review

We review and simultaneously introduce a convenient statistical concept for the mathematical representation of the Statistical Activity Cost Theory (SACT) introduced by Willett (1987, 1988). Further, we discuss, and present a critique of a variety of statistical models with respect to long debated accounting problems, such as the allocation of joint costs and depreciation. We finally propose that taking the effort to combine those models results in a novel statistical accounting system and this is discussed by means of the so-called virtual firm. Our approach is methodological rather than empirical. We endeavour to demonstrate that the statistical models presented herein have a more natural interpretation and applicability than their deterministic analogues: hence, this review presents promising outcomes and useful perspectives for the accounting profession.     

一种新的收入差距研究的计量方法——基于分布函数的半参数化估计

收入差距扩大的成因分解方法的最新研究强调描述整个收入分布,并且对收入分布的变化进行分解,进而得到各个统计量的分解,这类方法的优点是可以显示收入差距的变化主要集中在哪些收入群体中。本文着重介绍了两类对收入分布函数进行成因分解的半参数化方法:一类是Lemieux及其合作者们发展起来的权重重置法;另一类是Machado和Mata首创的基于分位数回归的分解方法。     

Renewed Interest in Work-sharing? Assessing Recent Developments in Germany

In the 1990s, attention has again been directed at prospects for work-sharing in response to threatened job losses. Various work-sharing agreements have been signed, especially in Germany, and most notably at Volkswagen. The Volkswagen agreements are considered, together with worker reactions and the prospects for the wider adoption of work-sharing.     

In Sickness and in Health: Recent Judicial Developments in Americans with Disabilities Act Association Discrimination Cases

A little-known provision of the Americans with Disabilities Act (ADA) prohibits covered employers from taking an adverse employment action against a qualified employee if a determinative factor in the adverse employment action is the disability of an associate or relative of the employee. A review of the reported court opinions indicates that plaintiff employees often encounter difficulty in these cases. Some plaintiffs are unable to prove that they are “qualified” employees at the time of the adverse employment action, and other plaintiffs find it difficult to prove that a determinative factor in the adverse employment action was the disability of the associate or relative. However, plaintiffs have achieved some success as evidenced in the 2008 U.S. Circuit Court of Appeals holdings in Dewitt v. Proctor Hospital and Trujillo v. PacifiCorp. This paper describes reported U. S. Circuit Court of Appeals opinions about ADA association discrimination, its relationship to the Family and Medical Leave Act and Employee Retirement Income Security Act, and the implications for employers, employees, and lawmakers. It also offers practical guidance to both employees and employers for asserting and managing rights and potential liability in this area.     

Recent Developments in Dealing with Item Non‐response in Surveys: A Critical Review

The most common way for treating item non‐response in surveys is to construct one or more replacement values to fill in for a missing value. This process is known as imputation. We distinguish single from multiple imputation. Single imputation consists of replacing a missing value by a single replacement value, whereas multiple imputation uses two or more replacement values. This article reviews various imputation procedures used in National Statistical Offices as well as the properties of point and variance estimators in the presence of imputed survey data. It also provides the reader with newer developments in the field.     

图像局部增强的算法研究及实现

为了不改变原有图像而增强图像局部的视觉效果,提出了一种新的基于局部均值和标准差的自适应图像增强算法。通过限定局部均值和标准差,选定需要增强的区域,并根据局部均值和标准差动态调整局部区域的增强系数。实验证明,该算法能够有效地增强暗的、低对比度区域,同时保持其他区域不变。