On the equivalence of location choice models: Conditional logit, nested logit and Poisson

It is well understood that the two most popular empirical models of location choice - conditional logit and Poisson - return identical coefficient estimates when the regressors are not individual specific. We show that these two models differ starkly in terms of their implied predictions. The conditional logit model represents a zero-sum world, in which one region’s gain is the other regions’ loss. In contrast, the Poisson model implies a positive-sum economy, in which one region’s gain is no other region’s loss. We also show that all intermediate cases can be represented as a nested logit model with a single outside option. The nested logit turns out to be a linear combination of the conditional logit and Poisson models. Conditional logit and Poisson elasticities mark the polar cases and can therefore serve as boundary values in applied research.     

Brain drain or brain bank? The impact of skilled emigration on poor-country innovation

The development prospects of a poor country or region depend in part on its capacity for innovation. In turn, the productivity of its innovators, whom are often concentrated around urban centers, depends on their access to technological knowledge. The emigration of highly skilled individuals weakens local knowledge networks (brain drain) but may also help remaining innovators access valuable knowledge accumulated abroad (brain bank). We develop a model in which the size of the optimal innovator Diaspora depends on the competing strengths of co-location and Diaspora effects for accessing knowledge. Then, using patent citation data associated with inventions from India, we estimate the key co-location and Diaspora parameters. The net effect of innovator emigration is to harm domestic knowledge access, on average. However, knowledge access conferred by the Diaspora is particularly valuable in the production of India’s most important inventions as measured by citations received. Thus, our findings imply that the optimal emigration level may depend, at least partly, on the relative value resulting from the most cited compared to average inventions.     

Is the division of labour limited by the extent of the market? Evidence from French cities

This paper provides supportive evidence to the notion that the division of labour is limited by the extent of the (local) market. We first propose a theoretical model. Its main prediction is that scarce specialists occupations are over-represented in large cities. Using census data for French cities, we find strong empirical support for this prediction.     

Spatial concentration and plant-level productivity in France

This paper analyzes empirically the effect of spatial agglomeration of activities on plant-level productivity, using French firm and plant-level data from 1996 to 2004. We exploit short-run variations of variables by making use of GMM estimation. This allows us to control for endogeneity biases that the estimation of agglomeration economies typically encounters. This means that our paper focuses on a subset of agglomeration economies, the short-run ones. Our results show that French plants benefit from localization economies, but we find very little - if any - evidence of urbanization economies. We also show that those localization benefits are relatively well internalized by firms in their location choice: we find very little difference between the geography that would maximize productivity gains in the short-run and the geography actually observed.     

民国时期(1927-1937年)城市规划机制探析

民国时期的城市规划法律文化有值得当今借鉴的因素,文章全面回顾民国前期城市规划机制的发展脉络,对1927年到1937年民国时期国家层面的城市规划主体、规划法律制度进行了探讨.在此基础上,初步总结了国民政府和伪满洲国的城市规划主体的主要构成和法律制度的主要内容,以及有益启示和教训.     

基于系统动力学的研发投资预算研究

研发投入是一种高风险的投资,研发投入过多或过少都不利于企业的发展,而如何在企业资源有限的情况下,合理安排研发投入以获取持续的竞争能力是企业研发管理的重点。应该说,研发投入系统是一种复杂的系统,本文首先对研发投资预算的方法进行了回顾,继而提出了运用系统动力学编制研发投资预算的思路并构建了基于系统动力学的研发投资预算模型,该模型将研发系统分为研发流程、研发团队和现金流等三个子模块并描述了研发投资预算的影响因素及其作用过程,最后,以电子产品为例运用该模型模拟了四种不同研发投资预算方案的效果。     

Investigating regional house price convergence in the United States: Evidence from a pair-wise approach

In this paper we examine long-run house price convergence across US states using a novel econometric approach advocated by Pesaran (2007) and Pesaran et al. (2009). Our empirical modelling strategy employs a probabilistic test statistic for convergence based on the percentage of unit root rejections among all state house price differentials. Using a sieve bootstrap procedure, we construct confidence intervals and find evidence in favour of convergence. We also conclude that speed of adjustment towards long-run equilibrium is inversely related to distance.     

美国2011年财政研发预算重点与趋势分析

在金融危机的压力下,美国联邦政府近两年的研发预算增幅甚微,2011年仅增加0．23％,但投向基础研究的资金增幅创下近五年新高,“气候”成为继“生物医学”之后又一大战略重点。本文简要分析美国联邦财政2011年研发预算的分布及其重点,及近年来美财政对研发战略投资的趋势。     

完善我国R＆D统计制度的对策思考

我国的R＆D统计始于20世纪80年代,至今已初步建立了依托于科技统计制度的符合国际标准的R＆D统计制度。但由于开展R＆D统计的时间较短,现行R＆D统计制度中还存在一定的缺陷,影响到统计数据的质量。文章结合笔者的调查情况,指出了我国R＆D统计在统计报表设计及统计工作组织方面存在的问题,并进行了具体分析,最后提出了完善R＆D统计制度的对策建议。