Public policies as specification errors

Treating public policies as computable dynamic general equilibrium model specification errors offers computational and conceptional advantages for comparing models with data. The set of policies calculated to rationalize observed behaviors raises the substantive economic question whether, in any particular market, actual public policies sufficiently coincide with the model's behavior-rationalizing policies, or whether the model offers correct hypotheses about the determinants of demand and supply. As illustrations, public policies are calculated to rationalize, with respect to the stochastic neoclassical growth model, capital market behavior since WWII and labor market behavior in 1929–1950. One conclusion is that capital taxation drives a wedge between consumption growth and the expected pre-tax capital return, in the direction and amount predicted by the theory, and that capital taxation is the major intertemporal distortion in the postwar capital market. Second, a good theory of the Great Depression labor market must explain why measured MRS and MPL diverged so dramatically in 1929–1933 and why the wedge persisted.     

The optimal portfolio for the two-pillar mandatory pension system: the case of Poland

In the recent decade, there has been observed across the Central and Eastern European states the regulatory trend towards the increase of the non-financial (first) pension pillar size at the expense of the financial (second) pillar. It tends to question the consequences of this shift for the future retirement benefits. Applying the portfolio approach we address this issue by running a series of simulations to find out how to allocate pension contributions between both pillars in an optimal way. Our study contributes to the existing literature as follows. First, we do not perform the assessment of the predetermined regulatory solutions, but we look for an optimal one. Moreover, we allow our optimal rule to be time-varying, if necessary, which would be a true novelty in this research area. Second, we do not base our estimates on historical trends; rather, we apply the long-term economy’s projection to account for the society’s ageing impact, which is a crucially important factor for the solvency of the pension system. Adapting some of the simulation assumptions to fit the Polish case, our results confirm that current regulations underestimate the role of the capital pillar and the optimal allocation between both pillars should be time-varying.     

Consistency and optimality in a dynamic game of pollution control II: Monopoly

This paper continues a line of research begun in Batabyal (1995a). I model the interaction between a regulator and a monopolistic, polluting firm as a Stackelberg differential game in which the regulator leads. The firm creates pollution, which results in a stock externality. I analyze the intertemporal effects of alternate pollution control measures. The principal issue here concerns the dynamic inconsistency of the optimal solution. Inter alia, I compare the steady state levels of pollution under optimal and under dynamically consistent policies.     

Take a risk: Preferring prevention over control of biological invaders

Scientists have argued that invasive species can be managed most cost effectively with greater investments in prevention. Further, under ideas like the precautionary principle it is reasonable to expect that a cautious manager would use more prevention relative to control because it keeps more invaders out. Yet, this is not typically done. In many cases, private and public resources are invested primarily to control existing invaders rather than to prevent new invasions. Managers frequently wait until after invaders have arrived and then scramble to limit the damages. We believe these paradoxical decisions can be understood by recognizing the link between typical human preferences for risk bearing and the technology of risk reduction. We demonstrate quantitatively how managers perceived to be cautious or averse to risk tend to shy away from prevention relative to control. This counterintuitive result arises because control is a safer choice than prevention because its productivity is relatively less risky: it works to remove existing invaders from the system. In contrast, the productivity of prevention is more uncertain because prevention only reduces the chance of invasion, it does not eliminate it, and invasion may not occur even in the absence of prevention. Managers' averse to risk will inherently avoid as much uncertainty as possible, whether the source of uncertainty regards ecological outcomes or economic productivity. Implications for environmental decision making are clear. In invasive species management, if managers act as though they are risk averse, their caution can backfire when it leads to more control rather than prevention. The social consequences of this choice are a greater probability of future invasions and lower social welfare. Our results suggest that social welfare is highest when managers were willing to “take a risk” with prevention.     

固定资产动态折旧的分类模型与通用模型构建

文章参照固定资产静态折旧的几种典型模型,构建了直线动态折旧模型、折旧基数变化情况下的加速动态折旧模型、折旧率变化情况下的加速动态折旧模型,分别根据各种折旧模型各自折旧额的内在规律性进行建模,比较好地实现了从静态折旧模型向动态折旧模型的转化.在此基础上,本文试图去寻找各种动态折旧模型中各期折旧额的共同规律,进而建立起固定资产动态折旧的通用模型,以供企业根据自己的实际情况代入相应初始条件直接套用固定资产动态折旧的通用模型,方便地计算固定资产各期的动态折旧金额.     

软件限时开发方法的研究与应用

限时开发是快速应用开发的最佳实践之一。文章介绍了限时开发的基本概念和优点以及适用的项目范围,通过一个进销存软件的开发实例说明如何成功地应用限时开发方法。     

The Dynamics of Capital Structure in Transition Economies

This paper uses a dynamic unrestricted capital structure model to examine the determinants of the private companies' target financial leverage and the speed of adjustment to it in two transition economies, the Czech Republic and Bulgaria. We explicitly model the adjustment of companies' leverage to a target leverage, and this target leverage is itself explained by a set of factors. The panel data methodology combines cross-section and time-series information. The results indicate that the Bulgarian corporate credit markets were less supply -constrained than those of the Czech Republic during the period under investigation. Bulgariancompanies adjusted much faster to the target leverage than Czech firms. The speed ofadjustment related positively to the distance between target and observed ratio for Bulgarian companies while the relationship was neutral for Czech companies. The conservative policies of Czech banks and the exposure control were likely responsible for the slower adjustment among the larger companies while the opposite were true for Bulgarian banks and companies.     

湖南怀化市河西新区市场群落发展研究

通过对湖南怀化市河西新区市场群落发展现状的调查考察,揭示了市场群落形成的动力机制,包括体制环境与路径依赖机制、区位优势与区域功能导向机制、政府扶持与政策优惠的加速机制、民营资本争利于市的驱动机制、外来经商人员和知名厂商的激活机制、产销一体化互动机制。针对区域整体规划滞后、市场重复建设、划行归市不甚理想、市场开发的房地产化趋势、投资环境欠佳等主要问题,提出了改善投资环境和经营环境、形成各部门协同发展合力,吸引经营大户和知名厂商进驻市场、培植市场主体商户,关注市场新变化、拓展新业态、发掘新空间,加强产销衔接、推进工贸一体化,强化市场人才培育等对策建议。     

Theory and practice of monetary policy

Summary. We consider an optimally managed renewable resource with stochastic non-concave growth function. We characterize the conditions under which the optimal policy leads to global extinction, global conservation and the existence of a safe standard of conservation. Our conditions are specified in terms of the economic and ecological primitives of the model: the biological growth function, the welfare function, the distribution of shocks and the discount rate. Our results indicate that, unlike deterministic models, extinction and conservation in stochastic models are not determined by a simple comparison of the growth rate and the discount rate; the welfare function plays an important role.Received: 20 October 2004, Revised: 28 February 2005, JEL Classification Numbers: D90, O11, O41, Q32.Santanu Roy: Correspondence toResearch on this paper was completed when the second author visited Cornell University in July, 2003. We thank the Center for Analytic Economics and the Department of Economics at Cornell University for making this research visit possible. The current version has gained considerably from the comments made by an anonymous referee.     

基于产品生命周期的物流系统动态规划研究

由于在产品不同生命周期阶段市场竞争具有不同的特征,因此企业采取的市场战略也有较大的差别。应用物流系统的动态评价方法,研究了有效支撑企业产品市场竞争战略的物流系统应该具有的关键性特征,并在此基础上分析了如何组织企业内外部的物流资源,使得物流系统成本最小化的动态规划问题。