Robustness checks and robustness tests in applied economics

A common exercise in empirical studies is a “robustness check”, where the researcher examines how certain “core” regression coefficient estimates behave when the regression specification is modified by adding or removing regressors. If the coefficients are plausible and robust, this is commonly interpreted as evidence of structural validity. Here, we study when and how one can infer structural validity from coefficient robustness and plausibility. As we show, there are numerous pitfalls, as commonly implemented robustness checks give neither necessary nor sufficient evidence for structural validity. Indeed, if not conducted properly, robustness checks can be completely uninformative or entirely misleading. We discuss how critical and non-critical core variables can be properly specified and how non-core variables for the comparison regression can be chosen to ensure that robustness checks are indeed structurally informative. We provide a straightforward new Hausman (1978) type test of robustness for the critical core coefficients, additional diagnostics that can help explain why robustness test rejection occurs, and a new estimator, the Feasible Optimally combined GLS (FOGLeSs) estimator, that makes relatively efficient use of the robustness check regressions. A new procedure for Matlab, testrob, embodies these methods.     

Exact confidence sets and goodness-of-fit methods for stable distributions

Usual inference methods for stable distributions are typically based on limit distributions. But asymptotic approximations can easily be unreliable in such cases, for standard regularity conditions may not apply or may hold only weakly. This paper proposes finite-sample tests and confidence sets for tail thickness and asymmetry parameters (α$\alpha$ and β$\beta$) of stable distributions. The confidence sets are built by inverting exact goodness-of-fit tests for hypotheses which assign specific values to these parameters. We propose extensions of the Kolmogorov–Smirnov, Shapiro–Wilk and Filliben criteria, as well as the quantile-based statistics proposed by McCulloch (1986) in order to better capture tail behavior. The suggested criteria compare empirical goodness-of-fit or quantile-based measures with their hypothesized values. Since the distributions involved are quite complex and non-standard, the relevant hypothetical measures are approximated by simulation, and p$p$-values are obtained using Monte Carlo (MC) test techniques. The properties of the proposed procedures are investigated by simulation. In contrast with conventional wisdom, we find reliable results with sample sizes as small as 25. The proposed methodology is applied to daily electricity price data in the US over the period 2001–2006. The results show clearly that heavy kurtosis and asymmetry are prevalent in these series.     

Meta‐Regression Analysis: A Quantitative Method of Literature Surveys

Abstract.  Pedagogically, literature reviews are instrumental. They summarize the large literature written on a particular topic, give coherence to the complex, often disparate, views expressed about an issue, and serve as a springboard for new ideas. However, literature surveys rarely establish anything approximating unanimous consensus. Ironically, this is just as true for the empirical economic literature. To harmonize this dissonance, we offer a quantitative methodology for reviewing the empirical economic literature. Meta‐regression analysis (MRA) is the regression analysis of regression analyses. MRA tends to objectify the review process. It studies the processes that produce empirical economic results as though they were any other social scientific phenomenon. MRA provides a framework for replication and offers a sensitivity analysis for model specification. In this brief essay, we propose a new method of reviewing economic literature, MRA, and discuss its potential.     

《公共场所英文译写规范》解读

本文对《公共场所英文译规范》中的逻辑结构和基本体例等基本要素制定展开了论述，并进行进一步解读，为所有规范该领域工作的相关部门和人员提供指导。     

Volatility activity: Specification and estimation

The paper examines volatility activity and its asymmetry and undertakes further specification analysis of volatility models based on it. We develop new nonparametric statistics using high-frequency option-based VIX data to test for asymmetry in volatility jumps. We also develop methods for estimating and evaluating, using price data alone, a general encompassing model for volatility dynamics where volatility activity is unrestricted. The nonparametric application to VIX data, along with model estimation for S&P index returns, suggests that volatility moves are best captured by an infinite variation pure-jump martingale with a symmetric jump compensator around zero. The latter provides a parsimonious generalization of the jump-diffusions commonly used for volatility modeling.     

世界范围VE/VM学术组织的建设及其对实践应用的推动

价值工程/价值管理(Value Engineering/Value Management,VE/VM)问世以来,许多国家和地区相继建立了学术性的组织机构,尤其在发达国家。这些组织名称各异,形式不同,但成立的宗旨、目的都相似。它们在普及VE/VM知识,开展技能培训和职业认证,制定标准规范,引导政府/企业界开展VE/VM实践应用,倡导学术研究和学者交流等方面,起到了重要作用。这些国家深入持久开展VE/VM活动,与这些组织机构的巨大推动作用是分不开的。文中对世界范围的这些VE/VM学术性组织的建设及其对实践应用的推动进行了综述,指出与发达国家的情况相比,中国目前在这一领域尚有很大的差距;如何学习发达国家在VE/VM领域的组织建设经验,对提升中国的VE/VM理论研究和实践发展,具有借鉴作用。     

Internet professionals: job skills for an on-line age

The paper explores the increasing popularity of the Internet technology Singapore. It argues that the diffusion of Internet technology to South-East Asia would create new duties and responsibilities for human resource (HR) managers. One such duty is the identification of the skills which professional Internet staff would need to perform their work effectively in organizations. Using a triangulation research method, empirical study has identified the new professional Internet jobs which have emerged the IT industry in Singapore and the skills that professional Internet personnel require do their jobs effectively. Analysis of the findings indicates that professional Internet skills involve both technical and creative abilities and that, in explaining or defining professional Internet skills, it is necessary to use both the technical and the social conceptions of skill. This argument is based on the view that the creative skills include tacit skills so that a definition based solely on the technical conception of skill cannot capture the various dimensions of Internet skills. The implications of the research findings for human resource managers are raised.     

计量经济学应用研究的可信性革命

可信性是计量经济学应用研究的重要问题,其核心在于实现经济理论、统计学、数学在实证研究中的科学结合。本文基于国际计量经济学界对可信性问题的三次大讨论取得的重要进展,厘清了计量经济学探索客观经济世界过程的本质特征;进而针对应用研究中存在的滥用和错用现象,从计量经济模型的随机性设定、经济变量之间的因果关系识别以及模型的统计适切性评价等三个方面阐述计量经济学应用研究的可靠性来源。我国计量经济学的应用研究面临进一步提高可信性的重要问题,需要全面吸收和借鉴国际计量经济学界对于可信性问题的成果,改变研究模式和教学模式。     

Specification and sensitivity analysis of cross-country growth regressions

We compare the sensitivity analysis of cross-country growth regressions based on extreme bounds analysis to a more direct specification testing approach using non-nested hypotheses tests. The results suggest that those specifications that are adequate are also those that include two of the only few conditioning variables that are found to be robust, namely the standard deviation of inflation and the standard deviation of domestic credit. First Version Received: November 2000/Final Version Received: May 2001     

MIS‐SPECIFICATION TESTING IN RETROSPECT

The primary objective of this paper is threefold. First, to undertake a retrospective view of Mis‐Specification (M‐S) testing, going back to the early 20th century, with a view to (i) place it in the broader context of modeling and inference and (ii) bring out some of its special features. Second, to call into question several widely used arguments undermining the importance of M‐S testing in favor of relying on weak probabilistic assumptions in conjunction with generic robustness claims and asymptotic inference. Third, to bring out the crucial role of M‐S testing in securing trustworthy inference results. This is achieved by extending/modifying Fisher's statistical framework with a view to draw a clear line between the modeling and the inference facets of statistical induction. The proposed framework untangles the statistical from the substantive (structural) model and focuses on how to secure the adequacy of the statistical model before probing for substantive adequacy. A case is made for using joint M‐S tests based on custom‐built auxiliary regressions with a view to enhance the effectiveness and reliability of probing for potential statistical misspecifications.