最优污染水平的数学解析与模式

针对环境经济学中最优污染水平概念模糊的问题，运用几何解析与逻辑推演方法，分析最优污染水平定性模式的病症所在，导出最优污染水平的充分条件和必要条件，并进一步运用导数和微分学理论证明了该充分条件和必要条件的正确性，从而创建了新的最优污染水平的定量模式。     

Asymptotic consequences of neglected dynamics in individual effects models*

We assess the asymptotic consequences of estimating static models based on cross-section or panel data, when in reality the data are generated by a dynamic relationship, involving lagged dependent and current and lagged exogenous variables as well as individual effects. If the exogenous variable follows a stationary process, then the static estimators usually underestimate its long-run effect. This inconsistency is less severe, the higher the autocorrelation of the exogenous variable. If the exogenous variable follows a random walk with or without individual-specific drift, then the estimators are found to be consistent for the long-run effect.     

政府监管对共享单车发展的影响——基于出行大数据的挖掘与分析

共享单车作为一种环保便捷的智能交通工具,由于过量投放、无序占道和运维错配等突出问题,严重影响公共秩序,政府监管势在必行。然而,政府严格监管对共享单车发展有何影响,一直在理论研究和社会实践中存在诸多争议。基于此,通过对成都中心区摩拜单车用户出行数据进行挖掘和分析,从政府、出行者和运营商视角,评估现行政府监管实施效果。研究表明,政府监管后,尽管出行意愿受到一定程度抑制,运维难度加大,但共享单车的公共属性得以强化,共享单车行业竞争格局得以调整,将有利于共享单车发展潜力的释放。     

Measurement error and panel data1

The underidentification of linear models with measurement error does not necessarily extend to panel data models, as has been shown by GAiliches and Hausman (1986). We discuss and extend some of their results for a simple case and address particular issues concerning identification and asymptotic variances.     

1990年以来江苏省区域经济差异时空格局演化及其成因分析

以1990—2007年江苏省县域人均GDP为研究指标,运用不平衡指数和空间统计模型对江苏省区域经济发展水平进行定量研究,并结合GIS的空间分析功能,系统分析了江苏省区域经济发展时空差异及空间格局演化。结果表明:江苏省区域经济发展在空间上具有较强的自相关性,在整体格局上呈现出一定的集聚态势,空间格局更多表现为苏南部分地区的高度集聚和苏北部分地区的集聚态势,成为江苏省区域经济发展的集聚核心区和低度集聚区,而苏中地区的集聚态势显得并不强烈。同时,针对区域经济自相关性发展趋势进行解释并指出以县域经济为单元的区域经济发展空间差异将长期存在。最后,构建空间数据模型对此种格局形成的原因进行空间统计学上的探讨,指出规模企业空间分布差异及人才空间分布差异是导致县域经济发展差异的主要因素,为区域经济差异分析提供了一种交互式的、可视化的新手段,进而为政府部门制定区域经济协调发展政策提供决策依据。     

TOOLS FOR RE‐RANDOMIZATION

With the rising popularity of field experiments in economics, re‐randomization schemes have emerged as tools to induce balance in observable variables across treatment groups. However, re‐randomization is not fully understood and the methodologies to estimate its effects on the distribution of parameters are still under‐developed. This paper helps to close that gap by suggesting an asymptotically normal re‐randomization scheme and bootstrapping procedure to carry inference under a wide range of estimators and re‐randomization schemes.     

Exact linear rank tests for two‐sample equivalence problems with continuous data

The present paper introduces a methodology for the semiparametric or non‐parametric two‐sample equivalence problem when the effects are specified by statistical functionals. The mean relative risk functional of two populations is given by the average of the time‐dependent risk. This functional is a meaningful non‐parametric quantity, which is invariant under strictly monotone transformations of the data. In the case of proportional hazard models, the functional determines just the proportional hazard risk factor. It is shown that an equivalence test of the type of the two‐sample Savage rank test is appropriate for this functional. Under proportional hazards, this test can be carried out as an exact level α test. It also works quite well under other semiparametric models. Similar results are presented for a Wilcoxon rank‐sum test for equivalence based on the Mann–Whitney functional given by the relative treatment effect.     

Compensating Wage Differentials with Unemployment: Evidence from China

We estimate the economic value of mortality risk in China using the compensating-wage-differential method. We find a positive and statistically significant correlation between wages and occupational fatality risk. The estimated effect is largest for unskilled workers. Unemployment reduces compensation for risk, which suggests that some of the assumptions under which compensating wage differentials can be interpreted as measures of workers’ preferences for risk and income are invalid when unemployment is high. Workers may be unwilling to quit high-risk jobs when alternative employment is difficult to obtain, violating the assumption of perfect mobility, or some workers (e.g., new migrants) may be poorly informed about between-job differences in risk, violating the assumption of perfect information. These factors suggest our estimates of the value per statistical life (VSL) in China, which range from approximately US$30,000 to US$100,000, may be biased downward. Alternative estimates adjust for heterogeneity of risk within industry by assuming that risk is concentrated among low-skill workers. These estimates, which are likely to be biased downward, range from US$7,000 to US$20,000.      

Bayesian inference in time series models using kernel quasi likelihoods

The paper takes up Bayesian inference in time series models when essentially nothing is known about the distribution of the dependent variable given past realizations or other covariates. It proposes the use of kernel quasi likelihoods upon which formal inference can be based. Gibbs sampling with data augmentation is used to perform the computations related to numerical Bayesian analysis of the model. The method is illustrated with artificial and real data sets.     

铁路行包办理站的优化方法研究

行包办理站的优化是一种基于全路车站行包办理量统计分析的优化方法。是解决多因素条件影响下铁路行包办理站址选择的依据。根据全路铁路行包办理站办理量及旅客列车加挂行李车编挂方案,按照始发终到、中途及中转车站作业情况,采用分析的方法给出了行包办理站设置的原则,并在此基础上得出未来行包办理站的优化方案。方案的执行可行性强,灵活且有针对性,对未来行包办理站的发展具有指导性意义。