Testing for normally in censored regressions

This paper derives a Lagrange Multiplier test for normality in censored regressions. The test is derived against the generalized log-gamma distribution, in which normal is a special case. The resulting test statistic coincides to some extent with previously suggested score and conditional moment tests. Estimation of the variance is performed by using the matrix of second order derivatives in order to get an easy to use test statistic. Small sample performance of the test is studied and compared to other tests by Monte Carlo experiments.     

On Testing Sample Selection Bias Under the Multicollinearity Problem

This paper reviews and extends the literature on the finite sample behavior of tests for sample selection bias. Monte Carlo results show that, when the “multicollinearity problem” identified by Nawata (1993) is severe, (i) the t-test based on the Heckman-Greene variance estimator can be unreliable, (ii) the Likelihood Ratio test remains powerful, and (iii) nonnormality can be interpreted as severe sample selection bias by Maximum Likelihood methods, leading to negative Wald statistics. We also confirm previous findings (Leung and Yu, 1996) that the standard regression-based t-test (Heckman, 1979) and the asymptotically efficient Lagrange Multiplier test (Melino, 1982), are robust to nonnormality but have very little power.     

变分迭代算法的应用

介绍了一种对求解非线性方程非常有效的方法-变分迭代算法及其发展成果．几个例子说明这种方法的有效性．     

DOUBLE LENGTH ARTIFICIAL REGRESSIONS FOR TESTING SPATIAL DEPENDENCE

This paper derives two simple artificial Double Length Regressions (DLR) to test for spatial dependence. The first DLR tests for spatial lag dependence while the second DLR tests for spatial error dependence. Both artificial regressions utilize only least squares residuals of the restricted model and are therefore easy to compute. These tests are illustrated using two simple examples. In addition, Monte Carlo experiments are performed to study the small sample performance of these tests. As expected, these DLR tests have similar performance to their corresponding LM counterparts.     

积极财政政策与制度约束-一种交易费用的解释

积极财政政策实施一段时间以来 ,效果还不是非常明显 ,其中一个原因就是存在着改革进程中制度结构变迁的非均衡 ,由于这种非均衡 ,经济系统内的交易费用呈现波动的态势 ,而本轮经济周期的谷地恰与交易费用的向上波动相逢 ,于是导致了以刺激需求为目的的积极财政政策的效应被部分抵消 ;同时传统文化习惯的相对稳定性也在一定程度上削弱了财政启动经济的作用。这提示我们 ,改革的各项措施的协调配合是非常重要的 ,而且改革的步伐也应该适当加快     

空间动态面板模型的时间滞后效应检验

空间面板数据模型由于考虑了经济变量间的空间相关性,其优势日益凸显,已成为计量经济学的热点研究领域。将空间相关性与动态模式同时扩展到面板模型中的空间动态面板模型,不仅考虑了经济变量之间的空间相关性,还考虑了时间上的滞后性,是空间面板模型的发展,增强了模型的解释力。考虑一种带固定个体效应、因变量的时间滞后项、因变量与随机误差项均存在空间自相关性的空间动态面板回归模型,提出了在个体数n和时间数T都很大,且T相对地大于n的条件下空间动态面板模型中时间滞后效应存在性的LM和LR检验方法,其检验方法包括联合检验、一维及二维的边际和条件检验;推导出这些检验在零假设下的极限分布;其极限分布均服从卡方分布。通过模拟试验研究检验统计量的小样本性质,结果显示其具有优良的统计性质。     

响应变量缺失下半参数变系数EV模型的约束统计推断

文章研究了半参数变系数EV模型在线性约束条件下的估计和检验问题,当响应变量缺失、非参数部分协变量带有测量误差时,利用局部纠偏的Profile最小二乘估计、Lagrange乘子方法和借补技术构造了回归模型参数分量两类纠偏约束估计量。此外,为了检验线性约束条件,构造了借补的Profile Lagrange乘子检验统计量,并通过蒙特卡洛数值模拟验证估计量和检验统计量的有效性。     

An LM-type test for idiosyncratic unit roots in the exact factor model with integrated factors

We consider an exact factor model with integrated factors and propose an LM-type test for unit roots in the idiosyncratic component. We show that, for a fixed number of panel individuals (N) and when the number of time points (T) tends to infinity, the limiting distribution of the LM-type statistic is a weighted sum of independent Chi-square variables with one degree of freedom, and when T tends to infinity followed by N tending to infinity, the limiting distribution is standard normal. The results should contribute to the challenging task of deriving likelihood-based unit-root tests in dynamic factor models.     

对影响货币乘数内在因素的实证分析和几点思考

1985年我国确立了中央银行体制下的货币供给管理体制.该体制中的三要素--基础货币、货币乘数和货币供应量之间的相互独立、相互依存的关系开始形成.它为我们从统计实证角度分析影响货币供给的内在因素提供了制度基础;1998年中央银行取消了信贷规模控制,提出了健全和完善以间接调控为主的货币政策工具,这对我们结合中国实际,从理论上分析我国基础货币的控制及货币乘数的稳定,提出了客观要求.     

货币政策区域效应乘数模型及在中国的应用

文章建立了基于宏观经济学经典理论的区域货币乘数模型和区域货币政策乘数模型,从理论上推导得出了货币政策区域效应的影响因素,并结合中国现实分析了中国基础货币区域投放差异、区域货币乘数差异、区域货币政策乘数差异。分析结果表明,在区域货币乘数和区域货币政策乘数的双重差异下,统一的货币政策对中国东部发达地区经济的影响效果将显著大于中西部欠发达地区。这些结论对中国货币政策制定和宏观经济调控具有重要意义。