Modelling dynamic storage function in commodity markets: Theory and evidence

In this work, we derive a model to investigate the optimal storage policy in metal commodity markets. From an inter-temporal setting, we carry out a criterion driving the stockholding decisions based on Tobin's q rule in which marginal benefits from holding inventories can be compared with marginal storage costs.We estimate the model for the world copper market by taking into account both spot price and convenience yield equations. In our sample, the estimated models are statistically robust and economically coherent with the theory, even though the patterns of the inventory accumulation process show high sensitivity to the uncertainty about worldwide economic conditions.     

出口退税、贸易盈余和外汇储备的一般均衡分析与中国的实证

本文构建了一个简单的大国开放经济一般均衡模型,从理论上探讨了外汇储备从贸易盈余时的短期均衡到贸易平衡时的长期均衡的动态变化过程,并在此基础上量化分析了降低出口退税率对长期均衡时的外汇储备的影响。研究表明,降低出口退税率在短期内对减少贸易盈余和控制外汇储备增量有一定的帮助,但长期来看则与出口产品的价格弹性密切相关,只有降低那些价格弹性较大的产品的出口退税率,才能够有效地减少长期均衡时的外汇储备,否则可能产生适得其反的效果。中国数据的实证研究支持了理论模型的结论。由于中国的出口产品总体缺乏价格弹性,因此,近年来实行的一系列出口退税政策改革在长期内使国家外汇储备出现了一定程度的增加。本文最后提出了相关的政策建议。     

能源经济与政策研究中的数据问题

近年来,能源经济与政策研究文献大幅增长,其中绝大多数属于经验研究或政策模拟分析,所使用的基础数据大多来源于政府部门或者国际组织发布的宏观统计资料或者在线数据库。目前有的研究存在较多基础数据问题,从而可能导致结论出现偏误。为厘清各统计量之间的逻辑关系、减少数据滥用或者误用的可能性、增强研究过程的透明度和研究结果的可比性,本文从经济学和国民经济核算等视角讨论了能源经济与政策研究中的数据问题。在开展能源经济研究时,需要明确界定系统的边界,明晰输入量和输出量,传统的发电煤耗法等线性加总方法可能会导致研究结论出现偏误,应用Divisia能源加总方法要更为精准。不同的数据源口径往往不同,来自统计部门的能源数据与经济数据可能并不完全匹配,国内外能源数据口径及其核算方法也存在较大差异。如果不注意这些差异,直接进行数据大小比较是不可取的,甚至可能会导致一些没有科学意义的争议。     

Specification choice and robustness in CGE trade policy analysis with imperfect competition

In order to contribute to a more comprehensive understanding of the robustness of the quantitative results of applied trade policy simulations to variations in the assumptions about firm conduct, this article provides a systematic synopsis of alternative formulations of imperfectly competitive supply behaviour in applied general equilibrium trade models and examines the sensitivity of simulated trade policy effects to the specification choice and calibration strategy within a prototype multi-country model. The analysis suggests in particular, that simulation results are generally far more sensitive to numerical specification choices at the calibration stage, than to the prior choice of firm conduct specification.     

Global Warming and a Potential Tipping Point in the Atlantic Thermohaline Circulation: The Role of Risk Aversion

The risk of catastrophes is one of the greatest threats of climate change. Yet, conventional assumptions shared by many integrated assessment models such as DICE lead to the counterintuitive result that higher concern about climate change risks does not lead to stronger near-term abatement efforts. This paper examines whether this result still holds in a refined DICE model that employs the Epstein–Zin utility specification and that is fully coupled with a dynamic tipping point model describing the evolution of the Atlantic thermohaline circulation (THC). Risk is captured by the possibility of a future collapse of the circulation and it is nourished by fat-tailed uncertainty about climate sensitivity. This uncertainty is assumed to resolve in the middle of the second half of this century and the near-term abatement efforts, which are undertaken before that point of time, can be adjusted afterwards. These modelling choices allow posing the question of whether aversion to this specific tipping point risk has a significant effect on near-term policy efforts. The simulations, however, provide evidence that it has little effect. For the more likely climate sensitivity values, a collapse of the circulation would occur in the more distant future. In this case, acting after learning can prevent the catastrophe, implying the remarkable insensitivity of the near-term policy to risk aversion. For the rather unlikely and high climate sensitivity values, the expected damage costs are not great enough to justify taking very costly measures to safeguard the THC. Our simulations also provide some indication that risk aversion might have some effect on near-term policy, if inertia limiting the speed of decarbonisation is accounted for. As it is highly uncertain how restrictive this kind of inertia will be, future research might investigate the effects of risk aversion if additional uncertainty about inertia is considered.     

CGE assumptions under scrutiny: uncertainty in the ethanol promotion policy in Mexico

Based on a CGE exercise of a subsidy to initiate ethanol production in Mexico, we use Monte Carlo simulations for consumer demand elasticities and ethanol cost estimates. The analysis provides three conclusions: when markets vary smoothly and predictably, Monte Carlo methods can then help to gauge the actual probability that a given program will achieve a desired outcome. Second, secondary markets may display little or no sensitivity to these parameter variations. Finally, a ‘razor’s edge’ outcome with no positive benefits if a critical parameter falls below some critical value, reveals that an economic policy may not be conducive to ‘fine tuning’ by marginal adjustments.     

中国八大综合经济区绿色全要素生产率增长测算与因素分解

随着绿色发展理念得到贯彻落实,科学测算与解析绿色全要素生产率增长对于经济高质量发展意义重大。为直接完整测度区域层面的绿色全要素生产率增长及其构成,本文构造聚合环境广义Luenberger-Hicks-Moorsteen生产率指标及分解子项,利用蒙特卡洛模拟检验该指标测算结果的有效性,发现其相对于聚合L指标更具优势。本文根据2003—2019年地级以上城市的投入产出指标数据,测算八大综合经济区的绿色全要素生产率增长及动力来源。结果表明,八大经济区绿色全要素生产率均实现增长,但增速呈现分化特征。八大综合经济区绿色全要素生产率增长在技术层面的动力主要源于技术进步与规模效率增长,在要素层面主要源于期望产出效率增长与非期望产出治理效率增长。技术进步和期望产出效率增长是八大经济区绿色全要素生产率增长差异的主要成因。本文结论对于有针对性地提升地区绿色全要素生产率具有启示意义。     

Simulation of the impact of economic policies on poverty and inequality: GEM in micro-simulation for the Algerian economy

This paper presents an illustration of the importance of computable general equilibrium modelling micro-simulation for simulating the impact of economic policies on living levels of households. The CGEM, as built, was used to simulate the effects of some economic policies on the economy and living levels of all households including the classes of modest, middle and wealthy households. In this context, pro-active economic policies are simulated in order to understand their effects on the macroeconomic plan and on the living level of some household categories defined according to statistical criteria. The first on the analysis of two arbitrarily selected tax policy cases, and the other on three investment policy simulations. Different illustrated simulations show improvements in economic growth and upward social mobility, particularly in the case of increasing the overall investment and improving productive capacity. In all simulations, that inequality would have remained rigid downward and would sometimes even accentuate. Overall, it appears that the increase in investment would boost economic growth through demand effect. However, this increase in demand would be met by more imports, which would damage our trade balance. The national productive system, however, could reverse this trend by making profitable investments by strengthening its productive capacity.     

Optimal fishery harvesting rules under uncertainty

This paper derives the optimal fishery harvest policy in a real-option model with a stochastic logistic growth process, harvest-sensitive output price, and both fixed and variable harvesting costs. The policy specifies the harvest trigger and harvest size, while outputs from the model include the value of the fishery and the risk of extinction. The optimal policy is illustrated with data from the Pacific Halibut Fishery. For this particular case, the optimal policy recommends harvesting when the fish stock rises to about three-quarters the environmental carrying capacity, and the amount harvested should be approximately a quarter of the prevailing stock. This harvesting policy maximizes the value of the fishery, and importantly, the resulting risk of extinction is negligible. We also carry out some sensitivity analysis to see how the optimal policy (and the resulting fishery value and risk of extinction) change when the input parameters are varied, particularly the ecological parameters intrinsic growth rate and volatility of the stock, and also the economic parameters that have been ignored in previous papers (price sensitivity and fixed cost). If the optimal policy is followed, the risk of extinction will be negligible, except for very low growth rate and high volatility.     

北京市下岗职工的再就业分析

该文利用独自收集到的有关北京市下岗职工的样本数据,分析了影响下岗职工失业持续时间的原因,探讨了影响下岗职工再就业前后收入变化的原因.通过分析得出以下主要结论:第一,下岗政策虽然在一定程度上促进了劳动力市场的形成,但随着下岗职工失业持续时间的延长,下岗政策已成为阻碍劳动力市场化的因素,同时也妨碍了市场经济体制下社会失业保障体制的建立和完善.第二,为了使更多的有在传统体制下工作经历的下岗职工,尤其是大量从事过企业管理工作的下岗职工尽快地实现再就业,不仅需要对他们进行各种技能的培训,而且更需要对他们进行如何适应新的经济环境的再教育.第三,"下岗"不仅是中国经济体制转型过程中的一个特殊时期的政策,实际上也是结构性失业在中国特有经济体制中表现出来的一种特有的现象.对于这种由于产业结构变化带来的失业问题,政府有必要制定更多的积极性的失业政策.     

国际金融危机背景下我国促进就业增长政策效应影响因素的实证分析

在2008年的次贷危机背景下,我国采取了一系列政策促进就业与经济增长,并取得了显著的效果。为了探寻政策实施效应影响因素及相互关系,在问卷调查的基础上,运用主成分分析提取了8个主要因素,并把8个因素分为政策因素与经济因素两个方面,运用典型相关分析方法分析二者之间的关系,提出了提高政府决策效率等相应政策建议。     

货币政策能否促进银行对小微企业信贷投放——基于宏观经济不确定视角的研究

本文研究在宏观经济不确定条件下,不同货币政策工具能否促进银行对小微企业信贷投放。首先,将货币政策引入考虑了宏观经济不确定性的银行资产组合模型中,论证货币政策、宏观经济不确定性与银行信贷资产配置的理论关系。然后利用我国181家银行2004—2018年的数据,检验在宏观经济不确定条件下,不同货币政策工具对银行小微企业信贷行为调控的作用效果。研究结果表明：宏观经济不确定性会抑制银行信贷行为。其中小微企业信贷占比较大的银行受到的影响更为显著。与数量型货币政策相比,价格型货币政策能够更显著地减轻不确定性对银行小微信贷的消极影响。其中银行同业拆借利率的调控效果最强。研究结论对于选择适宜的货币政策工具促进银行向小微企业信贷投放,化解经济不确定性对银行信贷行为的影响并助力小微企业发展等具有政策借鉴意义。     

Modelling monetary transmission in UK manufacturing industry

This paper studies the transmission of monetary policy to industrial output in the UK. In order to capture asymmetries, a system of threshold equations is considered. However, unlike previous research, endogenous threshold parameters are allowed to be different for each equation. Such an approach may be appealing from an economic point of view and is shown to be of importance after suitable econometric evaluation. Results show evidence of cross-sectional differences across industries and asymmetries in some sectors. These findings contribute to the debate about the importance of alternative economic theories to explain these asymmetries and support the use of a sectorally disaggregated approach to the analysis of monetary transmission.     

中国改革开放以来财政政策平滑经济波动的能力——基于传统IS-LM模型的实证分析

文章通过借助传统IS-LM模型和比较静态分析方法对中国改革开放以来财政政策平滑经济波动的能力进行了实证分析,得出:(1)财政政策对经济波动的整体平滑能力较低,平均只有6.35%,财政政策的平滑能力在经济波动的不同状态之间存在明显差异;(2)财政政策工具之间的平滑能力存在较大差异,其中财政购买性支出能平滑掉经济初始冲击的11.48%,而财政转移性支出和收入政策整体上反而使经济波动上升近3%;(3)内生性检验表明,中国只有相机性支出政策与经济波动之间存在显著的双向因果关系,不仅如此,相机性支出政策的内外时滞都较短。文章结论的政策含义是,提高中国财政政策稳定效果的关键在于提高政策工具的有效性与相互之间的协同效应,不仅如此,对经济高涨时期政府财政行为进行有效约束也至关重要。     

最优货币政策规则的选择及在我国的应用

本文首先根据我国的实际数据 ,建立和估计混合型模型 ,并以此作为研究货币政策规则的基本框架。然后在随机模拟的基础上 ,以社会福利为基准 ,计算和比较三种货币政策决策方式对社会福利的影响 ,这三种决策方式是完全承诺的最优货币政策规则、最优的Taylor规则及相机抉择。同时计算与福利损失等价的通胀率变化 ,结果表明 ,最优的Taylor规则能够很好地近似完全承诺的最优货币政策规则 ,这为进一步改进我国货币政策的决策和操作提供了一个指导方向。其次 ,对我国目前的货币政策决策和操作存在的问题进行分析 ,特别是对目前我国盯住货币供应量的体制所存在的问题进行分析 ,并提出改进的方案     

中国钢铁长期需求:影响因素与政策选择

近年来,我国钢铁工业得到了长足的发展。但随着国内外市场供求关系变化,钢铁工业供求结构不相适应的矛盾日益显现。钢铁工业要实现可持续发展,必须重视对市场长期需求规律的研究,将数量增长和产品结构调整相结合。本文利用协整方程对市场经济条件下经济增长等因素对我国钢铁工业推动作用进行动态分析,探讨钢铁市场的长期需求规律,对于当前钢铁产业政策发展导向、政策选择等提出建议。     

经济政策不确定性是否驱动制造业企业的“脱实向虚”*——基于中介效应及调节效应识别

当前，实体经济投资回报率低，制造业企业逐渐显现出“脱实向虚”的特征，主要表现为制造业企业金融化程度较为明显。本文使用2009—2019年中国A股制造业上市公司数据，研究了经济政策不确定性对制造业企业“脱实向虚”的影响。本文基于现金持有、实物期权和委托代理理论，进一步识别了两者关系的中介效应及调节效应，通过实证分析发现：（1）经济政策不确定性增加了制造业企业的“脱实向虚”程度；（2）融资约束对于经济政策不确定性和制造业企业“脱实向虚”之间的关系具有中介效应；（3）企业的股权集中度、客户集中度、银行监督程度均减弱了经济政策不确定性对制造业企业“脱实向虚”的正向影响。通过替换核心变量，本文在考虑所有制和规模异质性、政府补助的影响后，其主要结论仍然稳健。本文针对监管部门政策实施、流动性支持、资金流向监管等方面，提出了有针对性的建议。     

Central Bank independence: Low inflation at no cost? A numerical simulations exercise

The independent nature of the Central Bank is often associated with achieving low and stable inflation. Further to that the merits of independence are stretched to achieving low(er) output variability when compared to a government run monetary policy. In this paper we use the Alesina (1989) and Alesina and Gatti (1995) model to examine how often an Independent Central Bank can achieve an improvement on both counts. To do that we run numerical simulations where we change the ex ante probability of elections (and hence the degree of electoral uncertainty) with a view to determining how the private sector’s perceptions affect the level of output variability. Our conclusions agree with the Alesina and Gatti assertion that there will exist occasions when all political parties will be better off by consenting to the running of monetary policy by an independent institution but more often than not this comes at some cost to output. On theoretical grounds therefore, the trade-off between inflation and output variability (à la Rogoff) is still a valid one.     

Forecasting development outcomes under alternative surplus labour assumptions

Economic forecasts are useful to policymakers both as aids to planning, and as baselines against which counterfactual scenarios can be compared. However, policy makers should be aware that assumptions relating to model structure can influence forecast results. We explore the sensitivity of forecasts to one aspect of model structure important in modelling developing economies: surplus agricultural labour. We outline a framework for modelling surplus agricultural labour that relies on average product remuneration. We embed this within a model of a developing economy (the Philippines) characterized by surplus agricultural labour. We compare the results of two forecasts that differ in their treatment of the agricultural labour market. In the first, the surplus labour theory is activated, establishing average product remuneration in agriculture. In the second, the surplus labour theory is not activated, creating a failure to recognize average product remuneration in agriculture. By comparing the two simulations, we show that failure to model the presence of average product remuneration, when it would be appropriate to do so, has an impact that would be material to economic planners, leading them to: under-estimate agricultural employment; over-estimate GDP growth; and, over-estimate important policy variables (like tax revenue) that are related to GDP growth.     

自由贸易协定下中国贸易流量的影响因素研究——基于贸易引力模型的实证分析

近年来,随着经济全球化的迅速发展,我国开始实施自由贸易区战略,推进速度与规模令世人瞩目。以2000-2010年期间中国和14个贸易伙伴的贸易数据为样本,采用加入自由贸易协定等变量的扩展的引力模型对各因素对我国贸易流量的影响进行实证分析。结果显示:贸易国(地区)的经济规模、人口数量、文化以及贸易制度安排是影响我国对外贸易的主要因素,其中,自由贸易区的建立在一定程度上确实可以促进我国同贸易国(地区)的贸易流量,而距离对我国贸易流量的阻碍作用仍然十分显著。