Quantile regression with sample selection: Estimating women's return to education in the U.S.

This study uses quantile regression techniques to analyze changes in the returns to education for women. The data used is the March Current Population Survey for the years 1968, 1973, 1979, 1986 and 1990. The first step in estimating the single (linear) index selection equation uses Ichimura's (1993) semiparametric procedure. To correct for an unknown form of a sample selection bias in the quantile regression, the second step incorporates a nonparametric method, using an idea similar to one developed by Heckman (1980) and Newey (1991) for mean regression, and Buchinsky (1998) for quantile regression.  The results show that: (a) the returns to education increased enormously for the younger cohorts, but very little for the older cohorts; (b) in general the returns are higher at the lower quantiles in the beginning of the sample period and higher at the higher quantiles by the end of the sample period; (c) there is a significant sample selection bias for all age groups at almost all quantiles; (d) toward the end of the sample period there is a significant convergence of the returns at the various quantiles, especially for the younger cohorts and age groups; and (e) the semiparametric estimates of the selection equation are considerably different from those obtained for a parametric probit model.     

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的影响方向、程度和范围均存在较大空间差异。基于空间分布特征及要素回归系数空间差异,提出了传统村落开发利用的建议。     

山东上市公司财务危机预警研究

以1998年ST制度实施后山东省被ST的上市公司为研究对象,配以上市时间相同或相近的省内财务健康公司做控制样本,选取财务指标和非财务指标通过二元Logit回归建立了预测准确率高的模型,体现盈利能力的总资产收益率预测效果最显著。     

Regression Revisited

Sir Francis Galton introduced median regression and the use of the quantile function to describe distributions. Very early on the tradition moved to mean regression and the universal use of the Normal distribution, either as the natural ‘error’ distribution or as one forced by transformation. Though the introduction of ‘quantile regression’ refocused attention on the shape of the variability about the line, it uses nonparametric approaches and so ignores the actual distribution of the ‘error’ term. This paper seeks to show how Galton's approach enables the complete regression model, deterministic and stochastic elements, to be modelled, fitted and investigated. The emphasis is on the range of models that can be used for the stochastic element. It is noted that as the deterministic terms can be built up from components, so to, using quantile functions, can the stochastic element. The model may thus be treated in both modelling and fitting as a unity. Some evidence is presented to justify the use of a much wider range of distributional models than is usually considered and to emphasize their flexibility in extending regression models.     

改革开放以来广州经济增长因素分析

本文从实证角度建立计量模型,利用主成分分析方法和最小二乘回归的方法,对广州改革开放30多年以来的经济增长因素进行了具体分析,研究表明改革开放30多年来,广州经济增长的促进因素主要是劳动力数量的增长,经济制度的变革,产业结构的升级,以及人力资本增长的作用,物质资本不是促进广州经济增长的主要因素。     

陕西农户奶牛保险支付意愿的实证分析

陕西省于2007年7月在泾阳县实施了奶牛政策性农业保险的试点。本文按照条件价值评估方法,于2007年11月在泾阳县以支付卡式问卷调查对127户奶牛养殖户进行了实地调查,以调查数据为依据,测算了当地养殖户奶牛保险费用支付意愿,并运用Logistic回归模型分析了影响农户奶牛保险支付意愿的主要因素。结论认为,泾阳县奶牛保险试点中对畜龄2～8周岁奶牛实际征收保费标准低于养殖户平均支付意愿,是否接受保费、是否了解补贴、养殖户个体特征即受教育年限、养殖经验、年龄等是影响其保险支付意愿的主要因素。     

Problems with detecting assumed mediation using the hierarchical multiple regression strategy

In human resource management (HRM) and allied fields (e.g., organizational behavior, management, and industrial and organizational psychology), tests of mediation are frequently conducted using the hierarchical multiple regression (HMR) strategy of Baron and Kenny [Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182]. Although previous research has identified a number of serious problems with this approach, the present study adds to the literature by identifying yet additional problems with its use in inferring the existence of mediation. Using a statistical simulation, we found that certain patterns of correlation coefficients guarantee inferences about mediation, whereas other patterns preclude such inferences. On the basis of various analyses including logistic regression and inspection of three-dimensional plots, we identified patterns of correlation coefficients needed to satisfy Baron and Kenny's [Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182] conditions for inferring mediation. The same patterns have no necessary relation to actual causal connections among variables in mediation models. Moreover, as a consequence of the failure of the HMR strategy to detect mediating effects, many instances of actual mediation in HRM and allied fields may have gone undetected. In view of the foregoing, we conclude that the HMR strategy should no longer be used in testing for mediation.     

Relationship Between Human and Nature In America Literature

Nature is one of an important themes in America literature.This article mainly analyzes Ralph Emerson,Henry David Thoreau, Nathaniel Hawthorne,Jack London,Ernest Hemingway and Robert Frost's different representative stylistic works on nature;inquires into nature's various forms in America literature,such as its personification,objectification,deification and so on;elaborates on its significant meanings;expounds and proves the relationship between and nature in different writer's works and points out nature's profound impact on human.     

基于多变量的中国货币需求函数实证分析

随着我国经济体制改革的深化,建立货币需求模型的变量因子也在发生变化。然后,根据我国近年来货币实际需求,选取变量因子建立货币需求模型,并进行了实证分析。在实证分析的基础上,提出了提高货币政策有效性的政策建议。     

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。