分位数局部调整模型及应用

本文基于分位数的回归理论与方法,提出了一个新的经济计量模型:分位数局部调整模型,并给出了其数学表示、参数估计与预测方法等一整套建模技术。分位数局部调整模型能够细致地给出响应变量在各个分位点上的条件分位数,便于揭示响应变量位置、散布与形状等动态调整过程的全景信息,从而得到比均值局部调整模型更为深刻的结果。最后,将分位数局部调整模型应用于中国货币需求分析,结果显示,在货币需求的不同阶段,不仅调整速度不同,调整方式也呈现出非对称性;M1存在货币失踪之谜现象,而M2却在条件密度第一个最优区域实现了供求均衡;最优货币需求条件密度曲线较为分散,这为央行制定货币政策预留了足够的空间。     

Causality: a Statistical View

Statistical aspects of causality are reviewed in simple form and the impact of recent work discussed. Three distinct notions of causality are set out and implications for densities and for linear dependencies explained. The importance of appreciating the possibility of effect modifiers is stressed, be they intermediate variables, background variables or unobserved confounders. In many contexts the issue of unobserved confounders is salient. The difficulties of interpretation when there are joint effects are discussed and possible modifications of analysis explained. The dangers of uncritical conditioning and marginalization over intermediate response variables are set out and some of the problems of generalizing conclusions to populations and individuals explained. In general terms the importance of search for possibly causal variables is stressed but the need for caution is emphasized.     

Consistent estimation of a general nonparametric regression function in time series

We propose an estimator of the conditional distribution of X_t|X_t−1,X_t−2,…, and the corresponding regression function , where the conditioning set is of infinite order. We establish consistency of our estimator under stationarity and ergodicity conditions plus a mild smoothness condition.     

Combining forecasts for universally optimal performance

There are two potential directions of forecast combination: combining for adaptation and combining for improvement. The former direction targets the performance of the best forecaster, while the latter attempts to combine forecasts to improve on the best forecaster. It is often useful to infer which goal is more appropriate so that a suitable combination method may be used. This paper proposes an AI-AFTER approach that can not only determine the appropriate goal of forecast combination but also intelligently combine the forecasts to automatically achieve the proper goal. As a result of this approach, the combined forecasts from AI-AFTER perform well universally in both adaptation and improvement scenarios. The proposed forecasting approach is implemented in our R package AIafter, which is available at https://github.com/weiqian1/AIafter.     

Pseudo empirical likelihood method in the presence of missing data

In this paper, we propose an estimator for the population mean when some observations on the study and auxiliary variables are missing from the sample. The proposed estimator is valid for any unequal probability sampling design, and is based upon the pseudo empirical likelihood method. The proposed estimator is compared with other estimators in a simulation study.     

中国传统村落空间分布特征与影响因素分析

村落是乡村振兴战略实施的载体,认知传统村落空间分布及其影响因素对传统村落的传承和发展有重要价值。以中国传统村落为对象,采用核密度方法识别核心和次核心;构建"格网分析—空间自相关—地理加权回归"的影响因素研究方法,并进行实践分析。发现:①在地理格局上,传统村落主要分布在"胡焕庸线"以东、第二和第三级阶梯、年均降水量400 mm以上的区域、亚热带季风气候区和温带季风气候区;从行政区划来看,部分省份、地级市的交界地带为传统村落的密度核心。②GWR结果显示,对于地形因素,第二阶梯海拔越低、第三阶梯海拔越高传统村落越集中;对于生态因素,在农产品主产区或生态环境保护区,既出现生态环境越好传统村落越密集特征,也出现生态环境越好传统村落越分散特征;对于人口因素,"胡焕庸线"以西的大部分地区人口越密集传统村落越集中,而该线以东区域则相反;对于经济因素,中西部大部分经济发展水平较低的区域传统村落趋于聚集,东部地区经济水平总体较高传统村落趋于分散;交通和城市因素在不同区域对传统村落空间分布亦存在两面性特征。总体看,各地理要素的回归系数存在正负值、正负值比重差异以及高低值空间差异,反映各要素对传统村落空间分布...     

The non-linear impact of oil price on the oil demand

ABSTRACT

A panel smooth transition regression model was adopted to analyse the non-linear impact of oil prices on oil demand. Data for 42 countries was obtained from the International Energy Agency for the time period spanning from January 1990 to June 2017. The results indicate that a threshold value does exist. Furthermore, when the oil price was lower than this threshold value, a positive relationship between oil price and oil demand was observed. When the price of oil was higher than the threshold value, however, a negative relationship between price and demand was found.     

基于分组的异方差检验和两阶段估计

本文提出了一种基于分组的异方差检验法，并给出了存在异方差时的两阶段估计。     

人力资本与企业绩效关系的实证分析

国内外对企业绩效的实证研究主要是研究财务指标与企业绩效的关系,缺少对非财务指标的实证研究特别是人力资本与企业绩效关系的实证研究。本文选取反映人力资本的指标和反映企业绩效的指标,随机选取上市公司的数据进行多元回归分析,结果发现,员工高学历比例和员工专门技术人员比例,与企业绩效存在显著关系。笔者建议,要明确企业绩效与人力资本的关系,重视人力资本的作用,同时要结合行业特点和竞争程度综合考虑企业绩效。     

上市公司EVA实证分析——来自沪市制造业

本文以2001年沪市制造业93家上市公司的财务与交易数据为依据,采用相关分析和回归分析的方法,对EVA、传统会计指标与公司市场价值间的相关性进行了分析。结果表明:沪市制造业上市公司的EVA与MVA存在正向相关,且对MVA具有一定的解释能力,但其解释能力并不优于传统指标。现阶段EVA对MVA具有增量解释能力,但并不能替代传统指标。