Testing for unit roots in time series models with non-stationary volatility

Many of the key macro-economic and financial variables in developed economies are characterized by permanent volatility shifts. It is known that conventional unit root tests are potentially unreliable in the presence of such behaviour, depending on a particular function (the variance profile) of the underlying volatility process. Somewhat surprisingly then, very little work has been undertaken to develop unit root tests which are robust to the presence of permanent volatility shifts. In this paper we fill this gap in the literature by proposing tests which are valid in the presence of a quite general class of permanent variance changes which includes single and multiple (abrupt and smooth-transition) volatility change processes as special cases. Our solution uses numerical methods to simulate the asymptotic null distribution of the statistics based on a consistent estimate of the variance profile which we also develop. The practitioner is not required to specify a parametric model for volatility. An empirical illustration using producer price inflation series from the Stock–Watson database is reported.     

中国区域资本配置效率及区域资本形成影响因素的实证分析

本文构建了32组包含中国各行业近11万个数据的大型面板数据集,分行业系统测算了我国各区域的资本配置效率,并对区域和省际资本形成影响因素进行了系统的比较分析。研究发现:从短期来看,我国各地区的资本形成更加依赖于金融机构贷款的支持;绝大多数省份的资本形成存在自我约束、收敛的机制;不同省份间金融要素对固定资本形成的影响存在较大差异,说明我国地区之间存在一定程度的资本流动障碍。     

工具变量法综列单位根检验的有偏性及其修正

Chang（2002）基于非线性工具变量估计，提出了对截面相关综列数据进行单位根检验的SN检验，在综列数据生成过程不舍飘移和时间趋势时具有良好的表现。但我们的研究表明，在非平稳综列数据含有确定性趋势时，SN检验是有偏的，不再服从标准正态的渐近分布，而需要进行修正。本文基于蒙特卡罗仿真试验提出了一种简便的修正方法，修正后的SN检验统计量渐近分布为标准正态分布。仿真结果表明，修正后的SN检验具有更好的有限样本性质和较高的检验势。     

供应链固有可靠性和运作可靠性研究

依据供应链的不同阶段,将其可靠性分为固有可靠性和运作可靠性。为简化计算,提出供应链基本单元的概念,给出两种可靠性的分析方法。     

Evidence on corruption as an incentive for foreign direct investment

This paper assesses the relationship between corruption and inward foreign direct investment (FDI). Previous research has presumed that corruption directly enters the cost function of multinationals, suggesting a negative relationship between corruption and FDI. For a sample of 73 developed and less developed countries and the time period 1995–1999, we find a clear positive relationship between corruption and FDI. Corruption is thus a stimulus for FDI.     

Analyzing a panel of seasonal time series: Does seasonality in industrial production converge across Europe?

In this paper we consider deterministic seasonal variation in quarterly industrial production for several European countries, and we address the question whether this variation has become more similar across countries over time. Due to economic and institutional factors, one may expect convergence across business cycles. When these have similar characteristics as seasonal cycles, one may perhaps also find convergence in seasonality. To this aim, we propose a method that is based on treating the set of production series as a panel. By testing for the relevant parameter restrictions for moving window samples, we examine the hypothesis of convergence in deterministic seasonality while allowing for seasonal unit roots. Our main empirical finding is that there is no evidence for convergence in seasonality.     

改革以来中国农村发展地区差距分析

本文在扩展农业部门新古典经济增长模型的基础上,构建了基于农业生产率指数和农村地区劳动力就业结构的农村发展指标,以此来衡量农村发展水平及其变化状况.为了考察中国农村发展地区差距的变化趋势,我们采用面板数据单位根检验的不同方法对其收敛性进行了严格的计量检验.检验结果显示,在考虑了时间和省份特殊效应、序列相关等因素的影响后,中国各省农村发展差距以及东中西部地区农村发展的内部差距均存在条件性β收敛.     

Multiple aspect testing for case-control designs

When testing for the equality of two distributions in a case-control design with treatment effects presumed to act possibly on more than one aspect, different tests may be properly considered for testing for different features of a null hypothesis, leading to the multiple aspect testing issue. Two different aspects are therefore of interest: the location-aspect, based on the comparison of location indexes, and the distributional-aspect, based on the comparison of the empirical distribution functions. A simulation study shows that the combined testing procedure exhibits a good robust overall performance, and an application in biomedical research is also presented.     

Monotonicity of Rank Statistics in some Non–parametric: Testing Problems

For some non–parametric testing problems (one–sided two–sample problem, k –sample trend problem, testing independence against positive dependence) a partial ordering, denoted by ≥, over the alternatives is defined. This partial ordering expresses the strength of the deviation from the null–hypothesis. All familiar rank tests turn out to become more powerful under "increasing" alternatives; that is, all familiar rank statistics preserve the ordering stochastically in samples whenever it is present between underlying distributions. As a tool, the sample equivalence of ≥ is introduced as a partial ordering over pairs of permutations. Functions, defined on pairs of permutations, which preserve this ordering are studied.     

Testing equality of variances in the analysis of repeated measurements

The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman-Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.
The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies.