On the Endogeneity of the Mean-Variance Efficient Frontier

The endogeneity of the efficient frontier in the mean-variance model of portfolio selection is commonly obscured in the portfolio selection literature and in widely used textbooks. The authors demonstrate this endogeneity and discuss the impact of parameter changes on the mean-variance efficient frontier and on the beta coefficients of individual assets.     

Introduction to the Special Issue: Management in Africa in the Global Context 1

ABSTRACT

The primary focus of this introductory article is to provide a synoptic peek into the challenges and opportunities facing the countries of Africa in today's global economy and in their attempts to develop their national economies to achieve what is commonly termed the Millennium Development Goals. While foreign direct investment (FDI) is seen as a way to attain these goals, FDI flows to African countries remain extremely low. If Africa is to attract diversified FDI inflows, not just those focused on extractive/natural resources, African countries need to develop a system of management that is effective and efficient, internationally oriented and nationally focused, culturally inclusive and institutionally supportive and reliable, and one that promotes business growth and economic development with a sense of social responsibility.     

Organization governance form in franchising: efficient contracting or organizational momentum?

We examine firms' choice of organizational governance form. Using longitudinal data on a sample of business format franchisors operating in North America, we show that the cross‐sectional evidence commonly used to demonstrate support for efficient contracting explanations for organizational governance form is not robust to the year of investigation, firm effects, or selection effects. We theorize that this outcome may result from dynamic processes through which a firm's organizational governance form evolves. We develop and test two hypotheses for the effects of organizational momentum on organizational governance form, and find that organizational momentum is a robust predictor. Our results suggest that researchers consider the dynamics of momentum in explaining the form of firm governance. Copyright © 2008 John Wiley & Sons, Ltd.     

新常态下内需拉动经济增长是否存在有效边界*

新常态下,中国如何维持经济中高速增长既是重点,也是难点。由于外需拉动型经济增长方式逐渐难以为继,扩大内需的重要性日益突出。然而,扩大内需真的是有效国策吗？投资和消费拉动经济增长,是否存在有效边界？基于此,本文通过构建面板门限模型,利用2012-2013年中国275个市级数据,对内需拉动经济增长是否存在有效边界问题进行了实证检验。研究结果显示：投资拉动经济增长确实存在有效边界,当投资率较低时,增加投资能够有效拉动经济增长,当投资率已经较高时,增加投资对经济增长的拉动作用将不再显著;消费拉动经济增长也存在有效边界,当投资效率较低时,增加消费会抑制经济增长,当投资效率足够高时,增加消费才能够有效拉动经济增长。\     

京津冀城市可持续发展效率动态测评及比较研究——基于超效率CCR-DEA模型和Malmquist指数的度量

本文借助超效率 CCR-DEA 模型和 Malmquist 指数,对 2008~2015 年京津冀 13 个城市的可持续发展效率进行了动态测评和对应项分解。研究结果表明：（1）北京与津冀城市的可持续发展效率极为不平衡,北京大幅领先于津冀城市并有逐年扩大的趋势;津冀城市可持续发展效率的差距有逐年缩小的趋势;（2）京津冀城市作为一个整体其可持续发展效率在提高,但各城市可持续发展效率意义上的纯技术效率几乎没有提升;（3）京津冀各城市投入--产出系统虽处于可持续发展效率意义上的规模经济阶段,但不具有持续性。未来京津冀三地应充分利用建设雄安国家新区的战略性历史机遇,统一认识,密切合作,促进京津冀城市经济、社会和资源环境的协调可持续发展。     

基于现代物流技术的精确保障及我军构建策略

阐述了基于现代物流技术精确保障的内涵;结合伊拉克战争美军的保障实践,昭示了精确保障正成为信息化战争保障的发展趋势;就如何实现我军装备、后勤传统保障模式向精确模式的转型,提出了构建策略.     

漳州市农业资源可持续高效利用开发模式

随着漳州市农业的纵深发展,人口与资源的矛盾日趋尖锐,为缓解人多地少的矛盾和压力,解决农业可持续发展的问题,文章提出适合漳州地区推广的6种农业资源可持续高效利用开发模式。     

Peer effects in the diffusion of water‐saving agricultural technologies

We investigate the role of peer effects in the diffusion of an important water‐saving irrigation technology: low energy precise application (LEPA). Using detailed irrigation behavior data for growers in the High Plains Aquifer region of Kansas covering 1990–2014, we find clear evidence of peer influence in adoption of LEPA, net of environmental factors. Specifically, an additional neighboring LEPA installation within 1 km increases the probability of adoption by about 0.3 percentage points, on average, and this effect diminishes with distance. Our empirical estimates indicate that in the absence of peer effects, LEPA adoption would have been about 10% lower (1,000–1,600 fewer installations) per year. In addition, we find that growers install LEPA in response to higher energy prices.     

Value of hedge and expected returns

We demonstrate how it is possible to generate value for an investor with a hedge attached to the buy-and-hold strategy of an S&P 500 index fund. We study the S&P 500 index portfolio (not including dividends) and the value-weighted S&P 500 index portfolio (including dividends) of the Center for Research in Securities Prices for 1967:01–2011:12, using the capacity utilization and the unemployment rates in real time to determine if a hedge position should be initiated or closed. A hedge is initiated if the capacity utilization, the unemployment rate or a combination of the two signals a contraction in the real economy. The hedge position is closed if it signals otherwise an expansion. We use utility gains (Campbell and Thompson 2008), the manipulation-proof performance measure (MPPM) statistics (Ingersoll et al. 2007) and the P-Sharpe ratio (Bailey and López de Prado 2012) to evaluate the performance of a particular hedge strategy. The empirical results show that there are infinitely many hedges that can generate positive utility gains, higher MPPM statistics and higher P-Sharpe ratios.     

Alan Gillie,Input-Output Economics.

Turnovsky observes that “the rational expectations hypothesis has had a profound impact on macroeconomic theory and policy during the past decade.” Tracing briefly the evolution of the ideas involved, he concludes that “… a consensus view is emerging that in fact under quite plausible conditions the policy neutrality proposition does not hold; therefore, there is still scope for policy rules to play an important role in stabilizing output.”

The mathematics used in the article is expository rather than analytical, requiring of the reader only somewhat more than the usual amount of persistence, faith in the author's interpretation of the literature, and a willingness to accept the integrity of economic models as representative of the real world. This is “required” reading for those teaching macroeconomics.