存在遗漏变量时的内生性研究

存在遗漏变量时回归系数的估计是计量经济学的一个重要内容。本文讨论单方程计量经济模型中随机解释变量的内生性,指出了目前的计量经济理论所存在的问题,提出了普通最小二乘估计一致性判别的新方法,并证明了存在遗漏变量情况下的普通最小二乘估计仍是一致估计。     

On the assignment of students to topics: A Variable Neighborhood Search approach

This article presents a study of a practical assignment problem found in teaching within higher education. Here, students are assigned to scientific topics for which written papers must be submitted. Often, preferences across topics exist among other side constraints that should be considered in solving the problem of interest. Characterizing attributes of real-world problems were studied for scientific departments in Economics and Business Administration at German universities by sending out 800 questionnaires, and analyzing the 203 responses.Based on earlier studies, a Variable Neighborhood Search (VNS) approach was formulated to solve the resulting assignment problem. Several neighborhood search operators were tested, and numerical results are reported for a range of problem scenarios taken from real-world cases. It was observed that VNS leads to superior results vs. single operator local search approaches. Furthermore, we were able to show that in the studied problem, the effectiveness of certain neighborhoods was, to a large extent, dependent on the structures of the underlying problem.An extension of the problem was formulated by integrating a second objective function, which simultaneously balances the workload of staff members while maximizing student utility. The VNS approach was implemented in a computer system, available free of charge, providing decision support for selected other institutions within higher education.     

对统计学中变量的教学思考

变量是统计学中的一个基本范畴,但各类统计学教材对其定义不尽相同,造成理解混乱;笔者结合授课经验对变量概念进行了深入思考,以期使其日臻完善。     

企业创业导向与组织绩效关系的调节变量研究

企业创业导向与组织绩效关系的研究是目前公司创业领域中最受关注的议题,而不同研究发现创业导向对组织绩效的作用并不一致。在梳理前人研究成果的基础上,对影响企业创业导向与组织绩效关系的调节变量种类及其作用进行了归纳和总结,指出了目前相关研究的不足,并提出未来研究的方向。     

Fixed versus variable supply in the public provision of goods

Using discriminatory price auctions with variable supply, we explore a situation in which a corruptible public employee is in charge of producing and allocating a finite number of goods among consumers with uniformly distributed valuations. The negative effects of corruption are lower when the employee‘s task is to “provide at least q₀ goods” than when the employee is required to “provide exactly q₀ goods”.     

Dynamic risk management in petroleum project investment based on a variable precision rough set model

In this paper, an adaptive algorithm is designed for dynamic risk management in petroleum project investment based on a variable precision rough set (VPRS) model. In risk management, at each stage of decision-making, experts are invited to identify risk indices and support the decision-maker in evaluating the risk exposure (RE) of individual projects. The VPRS model is used to mine risk rules and determine the significance of risk indices from RE decision tables. Considering that there are multiple risks involved in any petroleum project investment, we use multi-objective programming to obtain the optimal selection of projects with minimum RE, where the significance of risk indices is assigned to each of the corresponding multi-objective functions as a weight. Moreover, we develop a risk ranking model to measure the degree of risk for individual projects in a portfolio. Finally, a numerical example based on a Chinese petroleum company's investments in overseas projects is presented to illustrate the proposed approach, and then conclusions are drawn.     

Human staff vs. service robot vs. fellow customer: Does it matter who helps your customer following a service failure incident?

The key to excellent service delivery is to ensure harmonious interactions between service actors. Therefore, in the event of service failure incidents, an understanding of the roles and interactions of these service actors is critical to achieving positive service outcomes. This research addresses the question: How do interactions between customers and these service actors (human staff/automated technological interface/fellow customer) influence their service experience following a service failure? We draw on role theory and answer this question via three experimental studies. Findings show that customers evaluate their service experience less favourably when receiving service recovery from fellow customers rather than firms (human staff and service robots). Furthermore, a firm’s instrumental recovery, rather than informational recovery, leads to a more favourable service evaluation, although this effect is absent when service recovery was given by fellow customers. Findings provide insights into the role of each actor in determining customer service evaluation.     

The effects of population density on subjective well-being: A case-study of Slovakia

The main objective of the study is to examine the effects of population density on individuals’ subjective well-being (SWB). The physical characteristics of the built environment have recently received more attention regarding their role in influencing well-being. The research is based on two waves of a representative survey EU-SILC (2013: N = 12,791 and 2018: N = 14,665). The study focuses on the emotional domain of SWB and uses a score based on the Mental Health Inventory (MHI-5). In order to remove the potential problem of reverse causality, a two-stage least squares regression model with instrumental variables is used. It shows that population density positively affects the SWB score. The results reported in this study can be useful for urban planning aimed at optimizing spatial structure while taking into account the factors which positively affect subjective well-being. The findings can also be beneficial for assessing the resilience and vulnerability of cities.     

保护性投资能促进森林公园的旅游发展吗？——基于森林公园层面的经验研究

本文利用2010~2016年森林公园及其所在市的宏观数据,构建面板数据,考察保护性投资对森林公园旅游发展的影响,并选取造林面积、林相改造作为缓解保护性投资内生性的工具变量,运用两阶段最小二乘法估计森林公园的保护性投资对其旅游发展的影响。研究发现:森林公园进行保护性投资并不能带来旅游收入和旅游人次的显著增加,反而导致旅游收入显著减少;保护性投资对森林公园的旅游收入和旅游人次的影响在不同等级、不同地区的森林公园之间存在显著的异质性;保护性投资的1期滞后项对森林公园的旅游人次增长具有积极影响,却无法显著地促进森林公园的旅游收入增长。