Pooled Panel Unit Root Tests and the Effect of Past Initialization

This paper analyzes the role of initialization when testing for a unit root in panel data, an issue that has received surprisingly little attention in the literature. In fact, most studies assume that the initial value is either zero or bounded. As a response to this, the current paper considers a model in which the initialization is in the past, which is shown to have several distinctive features that makes it attractive, even in comparison to the common time series practice of making the initial value a draw from its unconditional distribution under the stationary alternative. The results have implications not only for theory, but also for applied work. In particular, and in contrast to the time series case, in panels the effect of the initialization need not be negative but can actually lead to improved test performance.     

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.     

The Local Power of the CADF and CIPS Panel Unit Root Tests

Very little is known about the local power of second generation panel unit root tests that are robust to cross-section dependence. This article derives the local asymptotic power functions of the cross-section argumented Dickey–Fuller Cross-section Augmented Dickey-Fuller (CADF) and CIPS tests of Pesaran (2007), which are among the most popular tests around.     

A nonparametric hypothesis test for heteroscedasticity

In this paper, a hypothesis test for heteroscedasticity is proposed in a nonparametric regression model. The test statistic, which uses the residuals from a nonparametric fit of the mean function, is based on an adaptation of the well-known Levene's test. Using the recent theory for analysis of variance when the number of factor levels goes to infinity, the asymptotic distribution of the test statistic is established under the null hypothesis of homocedasticity and under local alternatives. Simulations suggest that the proposed test performs well in several situations, especially when the variance is a nonlinear function of the predictor.     

遗失物招领付费之研究

随着商品经济的发展,人们的道德素养并未上升到“圣人”的高度,拾而不还的行为在现实中逐渐成为一种较为普遍的现象。经中外对比研究,发现给予拾物人报酬请求权是解决该问题的一条有效途径,而“拾金不昧”的道德缺失也为遗失物招领付费制度提供了土壤。遗失物招领付费的做法在法理和实践中均有可行性,但在报酬比例的认定及该权利的排除适用上须谨慎对待。     

股票供给曲线凸现向后弯曲与理性投资决策

股票市场价格的高低及变动是对股票内在价值高低及变动的综合反映和表现,其价格的形成直接取决于市场的供求关系,而影响和调节股票供求量的并不是单位股票的绝对价格水平的高低及变动,它是股票作为投资品的单位内在价值的市场价格水平的高低及变动。由于股票收入效应和替代效应的存在又使股票供给曲线向后弯曲提升了股票的内在价值,这一表象成为引起股价波动背后的主要理性因素,从而为投资决策提供理性依据。     

Quasi-binomial zero-inflated regression model suitable for variables with bounded support

In recent years, a variety of regression models, including zero-inflated and hurdle versions, have been proposed to explain the case of a dependent variable with respect to exogenous covariates. Apart from the classical Poisson, negative binomial and generalised Poisson distributions, many proposals have appeared in the statistical literature, perhaps in response to the new possibilities offered by advanced software that now enables researchers to implement numerous special functions in a relatively simple way. However, we believe that a significant research gap remains, since very little attention has been paid to the quasi-binomial distribution, which was first proposed over fifty years ago. We believe this distribution might constitute a valid alternative to existing regression models, in situations in which the variable has bounded support. Therefore, in this paper we present a zero-inflated regression model based on the quasi-binomial distribution, taking into account the moments and maximum likelihood estimators, and perform a score test to compare the zero-inflated quasi-binomial distribution with the zero-inflated binomial distribution, and the zero-inflated model with the homogeneous model (the model in which covariates are not considered). This analysis is illustrated with two data sets that are well known in the statistical literature and which contain a large number of zeros.     

试论高等学校大型仪器设备的使用效益

我国正处于高等学校快速发展时期,全国各高等学校都不断加大大型仪器设备投资力度,管好、用好仪器设备成为当前高等学校设备管理工作的重点。本文就如何充分提高大型仪器设备的使用效益进行理论探讨,大胆提出从体制改革入手,改变原有的管理体制和管理模式,建立中心实验室,集中投资,合理配置,高效管理,开放使用,实现资源共享。     

电价波动的产业结构效应——基于CGE模型的分析

为探索电价波动与产业结构变化的关系,本文主要应用CGE(Computable General Equilibrium)模型对中国的电价波动与产业结构变化进行了实证研究。结果表明,各行业产出对电价的交叉弹性系数虽然很小,但耗电越多的行业对电价变化的反映越敏感。因此,本文认为,出于抑制高耗能产业膨胀、促进能效提高的目的,可以适当提高电价,但不能对电价的产业结构效应期望过高。同时应采取适当的电价调整方式,以避免电价波动的其他负面影响,促进电力合理利用和经济社会的可持续发展。     

中签率对IPO股票上市价格的揭示作用

在IPO(in ital pub lic offering)过程中,承销商比投资者更了解公司状况,而投资者本身也具有信息占据的异质性。基于此借鉴信号理论进行模型和实证分析,认为中签率的确可以作为一个信号将有关IPO股票内在质量的信息传递到市场上。具体说就是,中签率越高的IPO公司,将被市场识别为低内在价值公司,表现为较低的初始报酬率。