我国铁路基础设施噪声的边际成本定价方法研究

通过概述国内外学者关于运输外部性内部化政策、运输外部性评估、运输外部成本计算方法等方面的研究成果,阐述了美国及欧盟寻求实现运输外部成本内部化的政策和方法。针对我国铁路基础设施噪声污染问题,在分析铁路噪声的产生、传播及估算的基础上,研究提出利用边际成本定价方法计算铁路噪声边际成本。噪声定价方法还有支付意愿法、冲击路径法等,这些定价方法及其实证量化还有待进一步深入研究。     

Tourist preferences for ecotourism in rural communities adjacent to Kruger National Park: A choice experiment approach

This paper analyses the potential for development of ecotourism in rural communities adjacent to Kruger National Park (KNP) in South Africa. We determine preferences of tourists, according to origin and income levels, for ecotourism and their marginal willingness to pay (MWTP) for three ecotourism attributes: village accommodation, village tours and visits to crafts markets. Data were collected from 319 tourists through choice experiments, and analyzed using a conditional probit model. Findings indicate reluctance on the part of all tourists to use accommodation facilities outside KNP, but interest to purchase village tours and visit village-based craft markets. MWTP was negative for accommodation for all income groups, but positive for village tours and crafts markets. Among international and high income groups of tourists, tourists were willing to pay much higher fees than proposed by communities. These findings suggest the potential for development of some limited ecotourism services in villages adjacent to KNP.     

应该用哪一个模型来描述中国货币市场利率的动态变化

本文论证了双曲模型是描述中国货币市场利率动态变化的最佳单因子利率模型。由极大似然估计可以得到单因子利率模型的边际密度函数。双曲模型的边际密度和非参数估计得到的边际密度函数拟合较好,其表现远远优于几个常见的利率模型（CIR、CKLS和AG模型）。与较一般的Ait-Sahalia模型相比差别很小,但参数形式得到简化,似然比检验也支持这一点。双曲模型在刻画利率的均值回复特征方面还克服了AG模型的不足。     

Financial development,portfolio investments and the real economy in Africa

According to the conservative view, capital flows enhance economic growth. Focussing on Africa’s real economy, this study investigates the linkage between portfolio investments and real sector growth, and whether financial sector development strengthens this association. The study covers 30 countries over the period 1990–2017. We adopt the Lewbel instrumental variable general method of moments (IV-GMM) two-step robust estimator, which relies on heteroscedasticity for identification, while dealing with instrument insufficiency, unavailability, endogeneity and omitted variable bias. We found that portfolio equity has no growth impact on Africa’s real sector. Debt flows deter the growth of the overall real sector as well as the manufacturing and industrial sectors, but have no impact on agriculture and service growth. We found that financial development does strengthen the positive association between capital flows and economic growth, but this is dependent on the type of sector and portfolio investment, as well as on the degree of financial development. We control for known determinants of economic growth.     

Consistent inference in fixed-effects stochastic frontier models

The classical stochastic frontier panel data models provide no mechanism to disentangle individual time invariant unobserved heterogeneity from inefficiency. Greene (2005a, b) proposed the so-called “true” fixed-effects specification that distinguishes these two latent components. However, due to the incidental parameters problem, his maximum likelihood estimator may lead to biased variance estimates. We propose two alternative estimators that achieve consistency for $n\to \infty$ with fixed $T$. Furthermore, we extend the Chen et al. (2014) results providing a feasible estimator when the inefficiency is heteroskedastic and follows a first-order autoregressive process. We investigate the behavior of the proposed estimators through Monte Carlo simulations showing good finite sample properties, especially in small samples. An application to hospitals’ technical efficiency illustrates the usefulness of the new approach.     

Does Technological Innovation Really Reduce Marginal Abatement Costs? Some Theory,Algebraic Evidence,and Policy Implications

The existing literature models innovation in pollution control as a reduction in marginal abatement costs. We show that this assumption is inappropriate for production process innovations such as fuel switching. Algebraically, we examine the effects of different innovation types on marginal abatement cost curves, showing that some desirable innovations increase marginal abatement costs. Empirically, we estimate marginal abatement costs for sulfur dioxide by measuring the output distance function for electric power in Korea. Regression results confirm that production process innovations did raise marginal abatement costs in this case. One policy implication: economic instruments do not always provide stronger innovation incentives than command-and-control policies.      

Industry specific effects in investment performance and valuation of firms

A necessary criterion for a performance measure in corporate governance is the degree to which it mirrors how well the management succeeds in maximizing firm value. Such a performance measure is marginal q which links changes in firm value to the investments undertaken by the management. Empirical studies of investment and performance based on marginal q have demonstrated the usefulness of this measure. Most research however, has mainly focused on long-term performance. This paper takes a short-term perspective and, based on the marginal q-theory, considers how firms’ market values change in the extreme stock price cycle of a stock market bubble. Using a data set of listed Swedish corporations we find an anomaly in form of a new industry specific effect that, in addition to investment, explains changes in firm value.

On choosing which game to play when ignorant of the rules

This paper suggests a theory of choice among strategic situations when the rules of play are not properly specified. We take the view that a “strategic situation” is adequately described by a TU game since it specifies what is feasible for each coalition but is silent on the procedures that are used to allocate the surplus. We model the choice problem facing a decision maker (DM) as having to choose from finitely many “actions”. The known “consequence” of the ith action is a coalition from game f _i over a fixed set of players \(N_i\cup\{d\}\) (where d stands for the DM). Axioms are imposed on her choice as the list of consequences (f ₁,..., f _m ) from the m actions varies. We characterize choice rules that are based on marginal contributions of the DM in general and on the Shapley Value in particular.     

Marginal decision-making in the treatment of refractory epilepsy

Objective: Epilepsy surgery is one of the most effective treatments in modern medicine. Yet, it remains largely under-utilized, in spite of its proven efficacy. The referrals for epilepsy surgery are often delayed until it is too late to prevent the detrimental psychosocial effects of refractory seizures. The reluctance towards epilepsy surgery is influenced by the perceived risks of the procedure by practitioners and patients. This review discusses how, in general decision-making processes, one faces a natural tendency towards emphasizing the risks of the most immediate and operational decision (surgery), at times without contrasting these risks with the alternative (uncontrolled epilepsy).

Methods: In the field of economics, this bias is well recognized and can be overcome through marginal analysis, formally defined as focusing on incremental changes as opposed to absolute levels.

Results: Regarding epilepsy surgery, the risks and benefits of surgery are considered separately from the risks of uncontrolled epilepsy. For instance, even though surgery carries an ～0.1–0.5% risk of perioperative mortality, the chance of sudden unexpected death with refractory epilepsy can be as high as 0.6–0.9% per year. It is suggested that the inadequate way of phrasing clinical questions can be a crucial contributing factor for the under-utilization of epilepsy surgery.

Significance: It is proposed that examining decision-making for epilepsy surgery in the context of marginal analysis may enable providers and patients to make more accurate informed decisions.     

Does income inequality increase marginal propensity to consume?

This article empirically investigates the effects of income inequality on the marginal propensity to consume (MPC), using panel data of 22 OECD countries over the period 1994–2015. We find that MPC increases dramatically as income inequality increases. In subsample analyses, the MPC of a high inequality group is more than twice that of a low inequality group.