Connected Substitutes and Invertibility of Demand

We consider the invertibility (injectivity) of a nonparametric nonseparable demand system. Invertibility of demand is important in several contexts, including identification of demand, estimation of demand, testing of revealed preference, and economic theory exploiting existence of an inverse demand function or (in an exchange economy) uniqueness of Walrasian equilibrium prices. We introduce the notion of “connected substitutes” and show that this structure is sufficient for invertibility. The connected substitutes conditions require weak substitution between all goods and sufficient strict substitution to necessitate treating them in a single demand system. The connected substitutes conditions have transparent economic interpretation, are easily checked, and are satisfied in many standard models. They need only hold under some transformation of demand and can accommodate many models in which goods are complements. They allow one to show invertibility without strict gross substitutes, functional form restrictions, smoothness assumptions, or strong domain restrictions. When the restriction to weak substitutes is maintained, our sufficient conditions are also “nearly necessary” for even local invertibility.     

Identification of Standard Auction Models

This paper presents new identification results for models of first–price, second–price, ascending (English), and descending (Dutch) auctions. We consider a general specification of the latent demand and information structure, nesting both private values and common values models, and allowing correlated types as well as ex ante asymmetry. We address identification of a series of nested models and derive testable restrictions enabling discrimination between models on the basis of observed data. The simplest model—symmetric independent private values—is nonparametrically identified even if only the transaction price from each auction is observed. For richer models, identification and testable restrictions may be obtained when additional information of one or more of the following types is available: (i) the identity of the winning bidder or other bidders; (ii) one or more bids in addition to the transaction price; (iii) exogenous variation in the number of bidders; (iv) bidder–specific covariates. While many private values (PV) models are nonparametrically identified and testable with commonly available data, identification of common values (CV) models requires stringent assumptions. Nonetheless, the PV model can be tested against the CV alternative, even when neither model is identified.     

Identification in Differentiated Products Markets Using Market Level Data

We present new identification results for nonparametric models of differentiated products markets, using only market level observables. We specify a nonparametric random utility discrete choice model of demand allowing rich preference heterogeneity, product/market unobservables, and endogenous prices. Our supply model posits nonparametric cost functions, allows latent cost shocks, and nests a range of standard oligopoly models. We consider identification of demand, identification of changes in aggregate consumer welfare, identification of marginal costs, identification of firms' marginal cost functions, and discrimination between alternative models of firm conduct. We explore two complementary approaches. The first demonstrates identification under the same nonparametric instrumental variables conditions required for identification of regression models. The second treats demand and supply in a system of nonparametric simultaneous equations, leading to constructive proofs exploiting exogenous variation in demand shifters and cost shifters. We also derive testable restrictions that provide the first general formalization of Bresnahan's (1982) intuition for empirically distinguishing between alternative models of oligopoly competition. From a practical perspective, our results clarify the types of instrumental variables needed with market level data, including tradeoffs between functional form and exclusion restrictions.     

Workplace Job Satisfaction in Britain: Evidence from Linked Employer–Employee Data

The paper examines the nature of workplace job satisfaction in Britain using an ‘overall’ and domain‐specific job satisfaction outcomes from linked employer–employee data. A measure of aggregate job satisfaction alone might mask domain‐specific differences in satisfaction, something the combined approach in this paper addresses. As well as controlling for a rich set of correlates on employees and their workplaces, the paper deploys alternative empirical models that account for employee‐ and workplace‐level unobserved heterogeneity. The paper reports interesting results on the link between job satisfaction and observed as well as unobserved characteristics of employees and their workplaces.     

反补贴视角下的上网电价合法性分析——以欧盟“国家援助”审查为例

上网电价制度是否构成补贴,这一问题目前在WTO项下已经产生但尚无结论。欧盟在国家援助审查当中对此进行了回答。欧盟在十余起裁决当中先后树立了"资金来源"、"国家权力"、"国私企业是否一视同仁"三项标准。在欧盟项下,上网电价即便构成补贴,也会因特别法规定而获得合法性豁免。但在WTO项下,即便上网电价未必合法,目前各国也仍然通过"君子协定"维持其默示合规性。对于中国而言,目前可以充分利用上网电价制度,但应同时注重可再生能源激励机制的市场化。     

Research needs and priorities in housing and construction in Ethiopia

This paper attempts to present the main elements that are of central importance to housing problems and, in addition, gives an overview of the existing situations of housing research and construction activities in Ethiopia. It is hoped that such information may help the participants of the Seminar to suggest solutions in order to enhance the research and development for housing and construction activities and secure decent shelter for unfortunate urban groups in the developing countries.     

ERP系统的实施与代理成本——基于中国ERP导入期的证据

截止到2006年,我国企业基本完成了从认识ERP到导入ERP的过程.通过ERP系统的实施,越来越多的与企业运营相关的信息,如财务信息、物流信息等都通过ERP进行处理和优化,这样不但可以减少管理层与普通员工之间的代理成本,也可以降低股东计量、控制管理层行为的监督成本,进而进一步优化代理成本.基于此,本文研究了导入期ERP系统的实施对于我国上市公司代理成本的影响.研究结果表明,实施了ERP系统的公司,其代理成本显著降低;但是,实施了ERP系统的国有控股公司,其代理成本没有发生显著变化.     

荧光分析在农药研究中的应用

本文综述了荧光分析方法应用于氨基甲酸酯类农药,有机磷类农药,拟除虫菊酯类农药及新型烟碱类杀虫剂等残留量的快速测定。     

“国有企业补贴”的合法性分析——从中国诉美国双反措施案裁决谈起

美国商务部通过运用“多数股权”标准,将我国涉案国有企业直接认定为公共机构,且通过证据规则的设定,得出了我国国有企业向下游厂商提供产品这一行为是“国有企业补贴”这一结论.在中国诉美国双反措施案中,上诉机构对此进行了否定,并认定公共机构的法律标准应当在于“政府权威”的行使.否定美国商务部这一结论,对我国而言具有重大的意义,我国应当采用包括法律、政治在内的各种手段,保证此裁决的顺利实施.