Nonlinear IV unit root tests in panels with cross-sectional dependency

We propose a unit root test for panels with cross-sectional dependency. We allow general dependency structure among the innovations that generate data for each of the cross-sectional units. Each unit may have different sample size, and therefore unbalanced panels are also permitted in our framework. Yet, the test is asymptotically normal, and does not require any tabulation of the critical values. Our test is based on nonlinear IV estimation of the usual augmented Dickey–Fuller type regression for each cross-sectional unit, using as instruments nonlinear transformations of the lagged levels. The actual test statistic is simply defined as a standardized sum of individual IV t-ratios. We show in the paper that such a standardized sum of individual IV t-ratios has limit normal distribution as long as the panels have large individual time series observations and are asymptotically balanced in a very weak sense. We may have the number of cross-sectional units arbitrarily small or large. In particular, the usual sequential asymptotics, upon which most of the available asymptotic theories for panel unit root models heavily rely, are not required. Finite sample performance of our test is examined via a set of simulations, and compared with those of other commonly used panel unit root tests. Our test generally performs better than the existing tests in terms of both finite sample sizes and powers. We apply our nonlinear IV method to test for the purchasing power parity hypothesis in panels.     

城镇标准地块定位技术探讨

根据重庆市建立标定地价体系的科学实践．提出城镇标准地块空间定位的技术途径为：从分析土地级别内各定级单元土地质量空间分布规律或房地产市场价格空间分布规律入手，采用定级单元总分平衡法和房地产市场价格平衡法确定标准单元，依据功能特征评价成果将标准地块定位。     

单位犯罪死刑立法探研

单位犯罪死刑立法是指单位犯罪中自然人的死刑立法。我国刑法中单位犯罪死刑立法涉及19个罪名，包含两种立法模式：同等原则与区别原则。文章认为应采取同等原则的立法模式，但不赞同单位犯罪中为自然人配置死刑。建议取消刑法中13个单位犯罪的死刑。     

贵州经济增长与外国直接投资相关性的实证分析

通过运用协整技术和误差修正模型对贵州省1985～2003年期间的数据进行分析可知,贵州省经济增长与外国直接投资之间存在长期的动态均衡关系.从长期来看,外商对贵州的直接投资直接促进了贵州省经济的增长,经济增长与外国直接投资呈正向变动.但是这种促进作用还比较有限,而且对外国直接投资的影响作用不明显.     

市场化与经济增长:一个短期的因果关系检验

利用我国1999-2002年省际区域的面板数据,运用面板数据Granger因果关系检验技术,对我国市场化水平与经济增长的关联度进行了实证分析.得出市场化是经济增长的Granger原因,但是经济增长不是市场化的Granger原因的结论.     

软件限时开发方法的研究与应用

限时开发是快速应用开发的最佳实践之一。文章介绍了限时开发的基本概念和优点以及适用的项目范围,通过一个进销存软件的开发实例说明如何成功地应用限时开发方法。     

协整向量误设对相关检验的影响

常用于检验既定协整关系的统计量有tDF和tECM两种，但由于真实数据生成过程未知，估计模型中可能存在一定程度的协整向量误设，从而使统计量的分布特征受到影响。本文首先探讨tDF检验的隐含系数约束α=γ，即短期弹性等于先验长期弹性；其次分析零假设下两种统计量的分布特征，以及先验设定γ对信号噪声比q进而对tECM分布特征的影响；最后在局部备择假设下，给出两种统计量的渐近分布，并表明向量误设会降低协整检验的势，其程度与设定误差d正相关。     

Regional Unemployment in Transitional China: A Theoretical and Empirical Analysis

The purpose of this paper is to explain the pattern of regional unemployment in transitional China. A model is developed to explore how urban unemployment in the provinces is influenced by peasants' wages, formal sector wages, and the size of the formal sector. Evidence from panel data suggests that a significant indicator of high unemployment rates is greater Urban–Rural Income Inequality within the province. The hypothesis is that the urban–rural income gap produces migration, and more rural migrants substitute for urban workers, causing further urban unemployment.Since the economic reforms began in 1978, the non-state owned enterprises have been carrying an increasing weight in the economy, and they have contributed significantly to the rapid economic growth of China. Empirical evidence shows that economic reforms have reduced unemployment. The provinces that are still heavily dependent on the state sector are therefore more likely to experience higher unemployment.     

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.     

Two-sample rank tests with truncated populations

LetX ₁,…,X _m andY ₁,…,Y _n be two independent samples from continuous distributionsF andG respectively. Using a Hoeffding (1951) type theorem, we obtain the distributions of the vector S=(S ₍₁₎,…,S _(n)), whereS _(j)=# (X _i ’s≤Y _(j)) andY _(j) is thej-th order statistic ofY sample, under three truncation models: (a)G is a left truncation ofF orG is a right truncation ofF, (b)F is a right truncation ofH andG is a left truncation ofH, whereH is some continuous distribution function, (c)G is a two tail truncation ofF. Exploiting the relation between S and the vectorR of the ranks of the order statistics of theY-sample in the pooled sample, we can obtain exact distributions of many rank tests. We use these to compare powers of the Hajek test (Hajek 1967), the Sidak Vondracek test (1957) and the Mann-Whitney-Wilcoxon test. We derive some order relations between the values of the probagility-functions under each model. Hence find that the tests based onS ₍₁₎ andS _(n) are the UMP rank tests for the alternative (a). We also find LMP rank tests under the alternatives (b) and (c).