长江经济带高铁开通对第三产业集聚影响研究

高铁建设是中国交通基础设施建设史上具有标志性的重大事件,对区域要素流动、经济活动开展和产业空间格局构建影响深远。深入考察高铁开通与产业集聚的关系,对合理规划高铁建设和促进高质量发展意义重大。文章探讨了高铁开通引致第三产业集聚的空间溢出效应及其机制;立足高铁的时空效应,重点考察劳动力流动引致的知识溢出等效应对第三产业集聚的影响机理。通过构建空间双重差分模型,采用2007—2018年长江经济带108个地级市城市面板数据,实证检验长江经济带高铁开通对第三产业集聚的影响;不仅以空间滞后项的系数判断是否存在空间溢出效应,还以间接效应衡量空间溢出效应的程度。考虑长江经济带高铁网络布局不平衡、经济发展存在差距、资源禀赋不同的城市高铁开通后引起的效应可能有所区别,分区域及细分行业研究高铁开通对第三产业集聚影响的异质性;并进一步从劳动力转移视角实证检验高铁开通对第三产业影响的传导机制。研究表明：高铁开通不仅对长江经济带沿线城市第三产业集聚有显著的正向影响,其所引致的空间溢出效应亦明显促进了相邻城市的产业集聚。异质性检验结果表明,高铁开通对长江经济带东部城市第三产业集聚水平的正向作用高于中部城市,对西部城...     

基于解释结构模型（ISM）的临港产业发展分析

临港产业的蓬勃发展,已经成为沿海经济发展的主流趋势。通过对临港产业的内涵和特性的分析,认为临港产业是个复杂系统,其形成和发展受到诸多相关因素影响,各影响因素之间的关系复杂;运用系统工程的思想确定临港产业发展的影响因素,进一步分析了各个因素之间的联系;利用解释结构模型（ISM）系统化建模技术和计算机工具对诸要素的相互联系进行了逻辑运算,建立了影响临港产业发展的清晰的多级递阶解释结构系统;并且根据解释结构分级模型的结果,分析了影响临港产业发展的最直接和最根本的因素,提出了促进临港产业发展的一些建议,强调以港口竞争优势为特色,产业、港口和城市互动发展,才是临港产业持续健康快速发展的基石。     

Direct and Indirect Causal Effects via Potential Outcomes*

Abstract. The use of the concept of ‘direct’ versus ‘indirect’ causal effects is common, not only in statistics but also in many areas of social and economic sciences. The related terms of ‘biomarkers’ and ‘surrogates’ are common in pharmacological and biomedical sciences. Sometimes this concept is represented by graphical displays of various kinds. The view here is that there is a great deal of imprecise discussion surrounding this topic and, moreover, that the most straightforward way to clarify the situation is by using potential outcomes to define causal effects. In particular, I suggest that the use of principal stratification is key to understanding the meaning of direct and indirect causal effects. A current study of anthrax vaccine will be used to illustrate ideas.     

Analysis of a continuous-time proportional hazard model using discrete duration data

Many economic duration variables are often available only up to intervals, and not up to exact points. However, continuous time duration models are conceptually superior to discrete ones. Hence, in duration analyses, one faces a situation with discrete data and a continuous model. This paper discusses (i) the asymptotic bias of a conventional approximation procedure in which a discrete duration is treated as an exact observation; and (ii) the efficiency of a correct maximum likelihood estimator which appropriately accounts for the discrete nature of the data.     

Robust methods in econometrics

This survey of recent developments in robust estimation and inference is directed primarily toward econometricians. It is argued that many of the techniques in common use in econometrics are highly sensitive to unverified hypotheses. Recent progress in designing alternative robust procedures is described and some prospects for future developments are discussed.     

Critical evaluation of simulation studies in maintenance systems.

The purpose of this paper is to examine how far simulation studies of maintenance systems are neglecting simulation-related statistical issues. This negligence may leave simulation results suspicious and hard to explain. Several simulation factors are used to identify the strength of executed simulation experiments and to evaluate the level of clarity and reliability of the simulation models. The factors includes purpose of simulation, simulation model, model assumptions, distribution and random variables, simulation languages and computers, program verification and model validation, design of experiment, and analysis of the output. For this purpose, the literature is reviewed and subjected to the evaluation. It is observed that most papers define clearly their objectives, simulation languages, and model performance measures. However, verification, validation, experimental design, and output analysis are the most unclear factors.     

怎样的制造企业更愿涉足服务业务?———“服务化困境”问题的生产率匹配探析

本文关注于制造业企业服务化过程中的产业效率因素,设计了差异化产品模型。在需求层面,公司所提供的产品和服务之间具有互补性;而在供应方面,企业在产品生产和服务之间在专业知识分配上存在竞争。理论模型提供了对制造企业服务化与全要素生产率之间的计量评估。本文利用我国上市制造业版块中的企业数据,通过使用具有异质性的Fractional Probit 模型控制内生性并进行实证检验,理论模型推导和经验估计指出,企业全要素生产率与服务化之间存在“U”型关系,针对四个行业部门的检验也证实服务化和企业全要素生产率之间的非线性关系。在不同地区的企业之间,“U”型关系也存在差异。企业所处行业环境、所在区域以及所提供产品和服务的内在特征对于“服务化困境”的表现都存在差异性的影响。     

基于vSEIdRm模型的人口迁移以及离汉交通管控对新冠肺炎疫情发展的影响分析

不同于传统( Susceptible-Exposed-Infected-Removed)SEIR流行病传播动力学模型,本文在近期研究的Varying Coefficient Susceptible-Exposed-Infected-Diagnosed-Removed (vSEIdR)模型基础上加上人口迁徙(Migration) 模块,设计开发了vSEIdRm模型,该模型考虑了跨区域人口迁徙对疫情传播的影响,并允许流行病传播参数随时间变化。本文首先对人口迁移数据进行统计分析,建立其与各省新冠肺炎疫情发展的联系。之后,基于vSEIdRm模型估计了疫情初期各省份来自武汉的输入病例数,并定量刻画了离汉交通管控的效果。研究结果显示,离汉交通管控措施有效地减少了各省份的疫情规模。     

Hierarchical Bayes estimation of spatial statistics for rates

The U.S. Bureau of Labour Statistics publishes monthly unemployment rate estimates for its 50 states, the District of Columbia, and all counties, under Current Population Survey. However, the unemployment rate estimates for some states are unreliable due to low sample sizes in these states. Datta et al. (1999) proposed a hierarchical Bayes (HB) method using a time series generalization of a widely used cross-sectional model in small-area estimation. However, the geographical variation is also likely to be important. To have an efficient model, a comprehensive mixed normal model that accounts for the spatial and temporal effects is considered. A HB approach using Markov chain Monte Carlo is used for the analysis of the U.S. state-level unemployment rate estimates for January 2004-December 2007. The sensitivity of such type of analysis to prior assumptions in the Gaussian context is also studied.     

农村计划生育与农民生活满意度研究

基于6个省1586户农户的问卷调查数据,运用次序Logit模型,探讨农村计划生育、农村卫生事业、区域环境特征、农民个人特征、家庭特征对农民生活满意度的影响。结果表明,农村计划生育的两个因素中只有是否享受奖扶政策对农民生活满意度有显著影响,是否受过超生惩罚对农民生活满意度没有显著影响,农村卫生事业的两个因素,参加新型合作医疗制度以后看病是否改善和医疗支出负担对农民生活满意度都有显著的影响。根据分析结果提出以下政策建议:在今后的农村公共事业发展中,政府应渐进增加农村公共事业支出比重,进一步完善利益导向政策体系,适当提高奖励扶助标准,加大对农村超生家庭的处罚力度,使惩罚标准与收入及财产相对应。