Blocked-Error-R 2: A Conceptually Improved Definition of the Proportion of Explained Variance in Models Containing Loops or Correlated Residuals

Bentler and Raykov (2000, Journal of Applied Psychology 85: 125–131), and Jöreskog (1999a, http://www.ssicentral.com/lisrel/column3.htm, 1999b http://www.ssicentral. com/lisrel/column5.htm) proposed procedures for calculating R ² for dependent variables involved in loops or possessing correlated errors. This article demonstrates that Bentler and Raykov’s procedure can not be routinely interpreted as a “proportion” of explained variance, while Jöreskog’s reduced-form calculation is unnecessarily restrictive. The new blocked-error-R ² (beR ²) uses a minimal hypothetical causal intervention to resolve the variance-partitioning ambiguities created by loops and correlated errors. Hayduk (1996) discussed how stabilising feedback models – models capable of counteracting external perturbations – can result in an acceptable error variance which exceeds the variance of the dependent variable to which that error is attached. For variables included within loops, whether stabilising or not, beR ² provides the same value as Hayduk’s (1996) loop-adjusted-R ². For variables not involved in loops and not displaying correlated residuals, beR ² reports the same value as the traditional regression R ². Thus, beR ² provides a conceptualisation of the proportion of explained variance that spans both recursive and nonrecursive structural equation models. A procedure for calculating beR ² in any SEM program is provided.     

刍议“3+2”模式高职教育管理问题及对策

“3+2”模式高职教育管理问题日益凸现,课程设置部分重复,教育质量呈下降趋势,高职教育资源不能充分利用。文章从影响“3+2”模式高职教育管理质量的内、外部原因进行分析,提出了一些对策,以努力提高“3+2”模式高职教育的质量。     

论在中国B2C发展的若干问题

我国电子商务的环境在不断改善,接受网上购物方式的消费者越来越多.但2001年中国B2C并没有表现出太多令人欣喜之处,甚至部分曾经领先的电子商务网站不得不面对生死存亡的抉择.造成这种现状的原因不仅仅是电子商务整体的一些原因,也包括一些影响B2C发展的特有原因.如市场发育问题、互联网的环境和条件问题、信用制度完善的问题、物流配送问题、立法问题、具体经营问题等.这些瓶颈若不能得到合理的解决,对于电子商务发展的影响将会是巨大的.     

“智能+”时代背景下跨学科应用型物流人才培养模式探究

通过对“智能+”时代背景下应用型物流人才社会需求变化的调查分析,提出对现有物流专业在知识、能力、素质结构体系方面的调整建议,围绕“课程体系改革”及“教学工作改革”两个重点领域,依托“四个平台”,对构建创新型“智慧物流”专业的“ILTTM2+4”培养机制进行了深入探讨。     

Regulating Availability with Demand Uncertainty

Abstract. I evaluate a new German regulation that requires retail discounters to guarantee the availability of their products in bargain sales. The regulation is meant to prevent loss leaders. Retailers undermine the regulation's rationale by claiming that rationing is due to demand uncertainty. This paper shows that under demand uncertainty the regulation has ambiguous welfare effects. Effectively, it raises production, which, under imperfect competition, tends to be beneficial. However, the regulation overshoots and decreases welfare if it requires availability for a state of high demand that is relatively unlikely. In this case more sophisticated regulation is required.     

Buyer power and supplier incentives

This paper analyzes the origins and welfare consequences of buyer power. We show that if suppliers are capacity constrained or have strictly convex costs, there are two different channels through which large buyers can obtain more favorable terms from their suppliers. In particular, we show how the presence of large buyers can then erode the value of suppliers’ outside option. Somewhat surprisingly, we show how this can induce suppliers to undertake strategies that lead to higher output and potentially higher welfare.     

Efficient markets and Bayes’ rule

Summary. A series of financial anomalies motivated the development of new theories that modify the rational expectations ideal. Two possibilities have been systematically explored. The literature on behavioral finance relaxes the assumption that agents form beliefs according to the laws of probability and assume, instead, that simpler heuristic rules are used. Another stream of the literature assumes that agents process information according to Bayes rule, but do not posses sufficient information to know the true data generating process. In this paper, Bayesian and Behavioral agents coexist and trade in a standard dynamic asset pricing model. A long-standing conjecture is demonstrated. It is shown that, under suitable assumptions, Bayesian agents drive Behavioral, non-Bayesian agents out of the market. Hence, asset prices are eventually determined under the Bayesian paradigm.Received: 3 June 2004, Revised: 17 September 2004, JEL Classification Numbers: D83.Preliminary versions have circulated under the titles Markets Favor Bayesian Models and Market Selection of Empirical Models under Limited Information. I thank Larry Blume, David Easley, Larry Epstein, Armando Gomes, Bruce Hansen, Lars Hansen, Richard Kihlstrom, Grace Koo, George Mailath, Werner Ploberger, Andrew Postlewaite and Shakeeb Khan for useful comments. I also thank participants at the NBER GE meetings, Evolutionary Finance conference in Zurich, Latin American Meetings of the Econometric Society, Stanford Institute for Theoretical Economics, the Instituto de Matematica Pura e Aplicada, the theory seminar at Brown, Chicago, Harvard-MIT, Minnesota, Penn and Wisconsin. I gratefully acknowledge the financial support from the National Science Foundation Grant SES 0109650.     

Unilateral production restrictions in a dynamic duopoly

This paper examines a dynamic game of exploitation of a productive asset by a duopoly. A closed-loop Nash equilibrium of the game is constructed and used to analyze the effects of a unilateral production restriction. Surprisingly, such unilateral action may result in a decrease of the long-run asset's stock. We also exhibit production restrictions that can result simultaneously in an increase of the asset's stock and the long-run profits of the firm that is being imposed the production restriction. Moreover, a unilateral decrease of the production of one firm can induce its rival to also decrease its production.     

The impact of product diversification strategy on the corporate performance of large Spanish firms

We analyze the impact of product diversification on performance. This topic has been discussed in the literature, and there is no consensus so far as to the significance or the direction of the impact. Performance is measured using Tobin's q for a sample of 103 large, non-financial Spanish firms (1992–1995). Diversification is measured by means of a categorical variable, as suggested by Varadarajan. The principal results indicate that the firms with intermediate levels of product diversification have the highest performance, while the firms with low and high levels of diversification show significantly lower performance, which performance is not significantly different between them.