Asymmetric Forecast Densities for U.S. Macroeconomic Variables from a Gaussian Copula Model of Cross-Sectional and Serial Dependence

Most existing reduced-form macroeconomic multivariate time series models employ elliptical disturbances, so that the forecast densities produced are symmetric. In this article, we use a copula model with asymmetric margins to produce forecast densities with the scope for severe departures from symmetry. Empirical and skew t distributions are employed for the margins, and a high-dimensional Gaussian copula is used to jointly capture cross-sectional and (multivariate) serial dependence. The copula parameter matrix is given by the correlation matrix of a latent stationary and Markov vector autoregression (VAR). We show that the likelihood can be evaluated efficiently using the unique partial correlations, and estimate the copula using Bayesian methods. We examine the forecasting performance of the model for four U.S. macroeconomic variables between 1975:Q1 and 2011:Q2 using quarterly real-time data. We find that the point and density forecasts from the copula model are competitive with those from a Bayesian VAR. During the recent recession the forecast densities exhibit substantial asymmetry, avoiding some of the pitfalls of the symmetric forecast densities from the Bayesian VAR. We show that the asymmetries in the predictive distributions of GDP growth and inflation are similar to those found in the probabilistic forecasts from the Survey of Professional Forecasters. Last, we find that unlike the linear VAR model, our fitted Gaussian copula models exhibit nonlinear dependencies between some macroeconomic variables. This article has online supplementary material.     

Understanding Estimators of Treatment Effects in Regression Discontinuity Designs

In this paper, we propose two new estimators of treatment effects in regression discontinuity designs. These estimators can aid understanding of the existing estimators such as the local polynomial estimator and the partially linear estimator. The first estimator is the partially polynomial estimator which extends the partially linear estimator by further incorporating derivative differences of the conditional mean of the outcome on the two sides of the discontinuity point. This estimator is related to the local polynomial estimator by a relocalization effect. Unlike the partially linear estimator, this estimator can achieve the optimal rate of convergence even under broader regularity conditions. The second estimator is an instrumental variable estimator in the fuzzy design. This estimator will reduce to the local polynomial estimator if higher order endogeneities are neglected. We study the asymptotic properties of these two estimators and conduct simulation studies to confirm the theoretical analysis.     

Imposing and Testing for Shape Restrictions in Flexible Parametric Models

In many economic models, theory restricts the shape of functions, such as monotonicity or curvature conditions. This article reviews and presents a framework for constrained estimation and inference to test for shape conditions in parametric models. We show that “regional” shape-restricting estimators have important advantages in terms of model fit and flexibility (as opposed to standard “local” or “global” shape-restricting estimators). In our empirical illustration, this is the first article to impose and test for all shape restrictions required by economic theory simultaneously in the “Berndt and Wood” data. We find that this dataset is consistent with “duality theory,” whereas previous studies have found violations of economic theory. We discuss policy consequences for key parameters, such as whether energy and capital are complements or substitutes.     

Factor screening in nonregular two-level designs based on projection-based variable selection

In this paper, we focus on the problem of factor screening in nonregular two-level designs through gradually reducing the number of possible sets of active factors. We are particularly concerned with situations when three or four factors are active. Our proposed method works through examining fits of projection models, where variable selection techniques are used to reduce the number of terms. To examine the reliability of the methods in combination with such techniques, a panel of models consisting of three or four active factors with data generated from the 12-run and the 20-run Plackett–Burman (PB) design is used. The dependence of the procedure on the amount of noise, the number of active factors and the number of experimental factors is also investigated. For designs with few runs such as the 12-run PB design, variable selection should be done with care and default procedures in computer software may not be reliable to which we suggest improvements. A real example is included to show how we propose factor screening can be done in practice.     

A Proportional Hazards Regression Model for the Subdistribution with Covariates‐adjusted Censoring Weight for Competing Risks Data

With competing risks data, one often needs to assess the treatment and covariate effects on the cumulative incidence function. Fine and Gray proposed a proportional hazards regression model for the subdistribution of a competing risk with the assumption that the censoring distribution and the covariates are independent. Covariate‐dependent censoring sometimes occurs in medical studies. In this paper, we study the proportional hazards regression model for the subdistribution of a competing risk with proper adjustments for covariate‐dependent censoring. We consider a covariate‐adjusted weight function by fitting the Cox model for the censoring distribution and using the predictive probability for each individual. Our simulation study shows that the covariate‐adjusted weight estimator is basically unbiased when the censoring time depends on the covariates, and the covariate‐adjusted weight approach works well for the variance estimator as well. We illustrate our methods with bone marrow transplant data from the Center for International Blood and Marrow Transplant Research. Here, cancer relapse and death in complete remission are two competing risks.     

行政判例视野中的行政法原则研究——以梁宝福案、赖恒安案为例评释

行政法原则在行政执法实践和司法审判实践中具有重要意义,而行政判例中则蕴含着丰富的行政法原则.以梁宝富案关于合法性审查和保护诉权及赖恒安案关于成熟原则的行政判例为例来看,通过行政判例来运用、发展、创制行政法原则,对于推进我国行政法治有着极其重要的意义.     

高等学校自主权概念研究

高等学校自主权是一个极其复杂的概念,源于西方大学的自治权,就性质而言,有时表现为权力,有时又表现为权利;就内容而言,有的表现为权力,有的表现为权威.在我国的权力语境中,高校自主权就是指高等学校依据法律、法规的规定,以办学目标为基础,以学术自由为主要内容,按照自身特点和内部规律的要求,由其章程所规定、效力只及于内部成员的自主决策、自主实施、自主承担责任的资格和能力.     

Analysing non-doctrinal socialization: re-assessing the role of cognition to account for social cohesion in the Religious Society of Friends

To incorporate newcomers into membership, a group employs socialization strategies to transform the characteristics of the newcomers, so that it can admit them with the confidence that their behaviour will not endanger group unity. Analyses of socialization emphasize that novices' interiorization of an institutional definition of group behaviour is a necessary condition to ensure successful socialization. The contemporary Religious Society of Friends in Britain, however, is a non-doctrinal religious movement that avoids defining the content of its beliefs and practices. To analyse the socializing interaction between members and newcomers in this movement in Britain, and among co-religionists in the USA, this inquiry applies a model of socialization that does not include assumptions about the role played by cognition in socialization (Long and Hadden 1983). My results show that: (a) the diffuseness in Friends' collective explanations of institutional conduct supports novices' identification with institutional practice, and (b) experimental and affective components in socialization motivate novices to imitate institutional behaviour despite the fact that Friends have no authoritative explanations of such behaviour. The data suggest that socialization and social cohesion are not necessarily as strongly cognitive-oriented phenomena as they were previously thought to be. This finding has important implications for thinking about social cohesion in postmodern society.     

Migration Decisions of Dual-earner Families: An Application of Multilevel Modeling

A comprehensive framework for guiding analyses of internal migration is lacking. This study contributes to the family migration literature in three important ways. We develop a multilevel theoretical framework emphasizing an integration of individual-, family-, and neighborhood-level effects; introduce multilevel statistical modeling; and explicitly assess how effects of economic-based explanatory variables vary by gender. Our data are from the Panel Study of Income Dynamics (PSID). We find that the likelihood of a family migrating is affected by economic and non-economic factors, some of which vary by gender. We add to the dual-earner migration literature by finding that wives are not likely to be tied-movers, but husbands are likely to be tied-stayers. Neighborhood factors also are important to the decision to migrate.

阿拉伯语语法推理思维的文化探析

语法是语言的结构方式和组织规则,它兼具人类共性和民族个性.语法规则是人类长期抽象思维的成果和社团约定,它反映着语言社团的文化规约和语言学家的思维方式.阿拉伯语语法与汉语截然不同,与印欧语系语言相似,属于有明显形态标记的形式语法,具有清楚的逻辑推理思维,即遵循概念、判断和推理的基础模式.本文对此现象进行了阐释,并探究其文化成因.