International sanctions’ impact on energy efficiency in target states

This paper investigates the impact of international sanctions on energy efficiency by employing the panel fixed effect as well as average marginal effect from the Tobit model via data on 30 sanctioned states over the period 1996–2015 with international sanctions including unilateral, plurilateral, U.S., EU, UN, economic, and non-economic cases. Overall, we find that the imposition of unilateral sanctions leads to a 0.067% decrease in energy efficiency, but that of plurilateral sanctions positively contribute to energy efficiency in the case of the full sample of countries. Moreover, the imposition of UN sanctions has a greater decrease on energy efficiency in the target states than the 0.042% reduction of energy efficiency when the sanctionist is the U.S. For robustness, empirical results indicate that the imposition of plurilateral sanctions results in a drop of energy efficiency in Islamic countries, but an increase in non-Islamic countries, while there are also negative shocks induced by the imposition of EU sanctions on energy efficiency in Asian countries, but not for non-Asian countries. We also consider endogenous problems and dynamic specification by using indicator variables and System GMM. In summary, our empirical findings provide policy suggestions for those sanctioned countries about how to maintain energy efficiency when facing international sanctions.     

Heteroskedasticity-consistent covariance matrix estimators for spatial autoregressive models

In the presence of heteroskedasticity, conventional test statistics based on the ordinary least squares (OLS) estimator lead to incorrect inference results for the linear regression model. Given that heteroskedasticity is common in cross-sectional data, the test statistics based on various forms of heteroskedasticity-consistent covariance matrices (HCCMs) have been developed in the literature. In contrast to the standard linear regression model, heteroskedasticity is a more serious problem for spatial econometric models, generally causing inconsistent extremum estimators of model coefficients. This paper investigates the finite sample properties of the heteroskedasticity-robust generalized method of moments estimator (RGMME) for a spatial econometric model with an unknown form of heteroskedasticity. In particular, it develops various HCCM-type corrections to improve the finite sample properties of the RGMME and the conventional Wald test. The Monte Carlo results indicate that the HCCM-type corrections can produce more accurate results for inference on model parameters and the impact effects estimates in small samples.     

碳排放交易制度的节能减排路径：效率提升还是结构转型？——来自中国省级数据的准自然实验

以中国2013年以来实行的碳排放交易试点政策作为准自然实验事件，基于2000-2017年中国30个省市的面板数据，运用双重差分法实证检验碳排放交易制度的节能减排效应及影响机制。研究发现，碳排放交易制度有利于实现中国经济“节能”与“减排”的双重目标，并通过了一系列稳健性检验；作用机制检验表明，能源效率提升和能源结构转型都是碳排放交易制度实现节能减排目标的重要路径；能源效率提升在碳排放交易制度实现“节能”和“减排”中分别发挥了10.19%和5.93%的作用，而能源结构转型分别发挥了48.87%和52.95%的作用。这意味着中国碳排放交易制度实现节能减排的主要动力来自能源结构转型，而非能源效率提升。能源结构转型涉及问题更加宏观和深层，这为中国加快推进节能减排进程，特别是完成2030年碳达峰和2060年碳中和的国际承诺提供政策启示。     

中国粳稻生产效率演变及区域差异

[目的]我国粳稻产量现阶段呈连续增长的态势,然而粳稻生产效率却存在无效率或波动剧烈的现象,研究我国的粳稻生产效率,有助于提升和稳定中国粳稻区域生产效率和水平从而间接保障我国粮食安全。[方法]使用超效率DEA方法测算中国13个粳稻生产省份的生产效率,分别从时间和区域上的差异进行分析。[结果]中国粳稻生产技术效率在时间趋势上逐渐趋于平稳,但是在2004—2007年间存在短暂的波动;在区域上主要是西南和东北粳稻生产区的技术效率水平较高,西北区在技术效率、纯技术效率与规模效率上都处于较低的水平;虽然河南、湖北、宁夏3个省份出现技术无效率,但规模报酬都处于递增的状态,仍有提升生产效率的潜力,应通过减少要素投入冗余来改变其无效率状态。[结论]粳稻生产技术无效率主要是由于种子费用、农药费用等生产要素的投入冗余造成的;若将来在保持纯技术效率和其他条件不变的情况下,通过提升规模效率水平会进一步提升我国粳稻的整体技术效率水平。基于上述分析有针对性地提出制定粳稻生产区域规划、发展适度规模经营、改善生产要素使用效率3方面的政策建议。     

农作物面积抽样单元空间变异性及其对抽样外推效率的影响

［目的］联合遥感和传统抽样方法的空间抽样技术是进行大区域农作物面积监测的有效手段。但传统抽样要求抽样单元间相互独立，并未考虑到区域农作物空间变异性的存在对农作物面积空间抽样效率是否有影响及其影响程度如何，从而限制了农作物面积监测的效率和精度。［方法］文章以吉林省德惠市为研究区，利用变异函数分别对10种抽样单元尺度内玉米和水稻种植面积的空间变异性进行定量评价。选择3种空间抽样方案（简单随机抽样、系统抽样、分层抽样），分别计算不同空间变异程度下的样本容量（n）、抽样相对误差（Re）和总体总值估计量的变异系数（CV（Y︿））作为空间抽样效率的评价指标，定量分析空间变异性对农作物面积空间抽样效率的影响，提出适宜空间变异农作物的空间抽样优化方案。［结果］(1)玉米和水稻面积的空间变异性（反映为基台值C0+C）均随着抽样单元尺度的增加逐渐而减小，其中500m×500m和2 500m×2 500m抽样单元尺度下农作物面积的空间自相关程度相对最小。(2)相同抽样比下，农作物面积在3种抽样方法下的相对误差和变异系数均随着空间变异性的减小（抽样单元尺度增加）逐渐增大，其中玉米和水稻在分层抽样条件下的相对误差和变异系数具有相对最小值，分别限制在10%和20%以内，其次为系统抽样（Re<40%，CV（Y︿）<88%）和简单随机抽样（Re<50%，CV（Y︿）<75%）。 在抽样方法被选定的情况下，两种农作物的分层抽样相对误差变化率随着抽样比的增加迅速降低，当抽样比增至5%时，其相对误差和变异系数的变化率基本趋于稳定，继续增加抽样比来提高抽样精度的效果甚微。 在3 500m×3 500m抽样单元尺度内，按5%抽样比确定的样本容量对玉米和水稻面积进行分层抽样时，可达到95%的抽样精度（Re<5%）。 综合农作物在不同抽样单元尺度下的空间变异特征和空间抽样效率，基于2 500m×2 500m的抽样单元尺度和5%抽样比进行分层抽样的空间变异性农作物空间抽样方案是一种高精度、低成本、代表性强的空间抽样方案。［结论］该研究为区域农作物面积抽样调查方法的改善和抽样效率的提高提供技术支持和参考依据。     

生态文明建设背景财政扶持、林权改革对林业生产效率的影响

基于2000—2016年中国省际面板数据,利用DEA-Malmquist指数法对中国林业生产效率的区域差异和时序变化进行研究,运用面板Tobit模型检验财政扶持对林业生产效率的影响并验证林权改革对二者关系的调节作用。研究发现:在生态文明建设背景下,林业生产效率存在显著的区域差异;技术进步对于全要素生产率的提升起到重要推进作用;财政扶持与林权改革均对林业生产效率产生了正向影响,但林权改革并没有对财政扶持与林业生产效率的关系产生积极调节作用。因此,各省份应当通过加大政府扶持力度、优化投资方式、深化集体林权制度改革等措施促进林业生产效率提升。     

Airports’ managerial human capital,ownership, and efficiency

Airport performance differences require a better understanding of the sources of efficiency and competitive advantages. Globalization drives the air transport industry into a more market-orientated business questioning the relationship between managerial decisions and airport performance. Aviation management studies do not consider managerial capabilities and skills since they are intangible exogenous factors that are difficult to assess. In this study, a stochastic frontier analysis is performed accounting for top managers' theoretical knowledge and experience enclosed as exogenous drivers of airports' efficiency. The model analyses 12 Polish airports from 2009 to 2017. The results show a diversity of airports with a different number of passengers as efficient. The top managers' experience, when gained in the same airport, has a positive impact on airports' technical efficiency. Airports having unstable management are more technically inefficient. Independently of the efficiency level, some airports change their management after the national elections, suggesting that managers are chosen by political interest rather than by their specialised knowledge or their prior experience in aviation management. The results suggest that more practical knowledge improve airports’ performance. Airports with a majority of government ownership that are the largest ones increase their efficiency significantly, suggesting that political decisions may be discriminatory in detriment of airports managed by regional and city authorities.     

非农就业对种植决策的影响*——基于土地地势的研究视角

［目的］农村劳动力非农转移影响农户农业生产方式变迁，土地质量差异造成的生产差异会随着农村劳动力非农转移造成的人力投入减少而更加显现。针对农户的市场经济行为，文章从理论及实证角度探讨农户农业劳动投入减少时农户生产决策的变化，并根据实证结果进一步探讨我国农业种植结构的变化趋势，为相关政策的制定提供决策参考。［方法］该文运用多元回归模型，从土地资源异质性的视角分析了劳动力非农就业后在不同地势耕地的农业生产决策变化。［结果］劳动力非农就业明显影响了农户种植决策，在质量较高的平地上，农户的生产决策是种植机械化生产使用高的粮食作物来减少劳动力投入下降，在质量较差的山坡地上，农户的生产决策是降低对山坡地的使用强度来解决劳动力投入不足问题，具体表现方式是降低粮食种植面积以及抛荒方式来分配家庭农业劳动投入。［结论］不同地势耕地利用强度将会出现不同变化，平原以及交通便利地区，可以通过机械来替代人力投入，交通较为不发达的山区丘陵地区，需要通过加大农业基础设施建设等来解决山区丘陵地区的抛荒问题。政策支持方面，鼓励中低产田提高产品产量与提升降本技术，保障与维护国家粮食安全。     

Inference for large financial systems

We treat the parameter estimation problem for mean‐field models of large interacting financial systems such as the banking system and a pool of assets held by an institution or backing a security. We develop an asymptotic inference approach that addresses the scale and complexity of such systems. Harnessing the weak convergence results developed for mean‐field financial systems in the literature, we construct an approximate likelihood for large systems. The approximate likelihood has a conditionally Gaussian structure, enabling us to design an efficient numerical method for its evaluation. We provide a representation of the corresponding approximate estimator in terms of a weighted least‐squares estimator, and use it to analyze the large‐system and large‐sample behavior of the estimator. Numerical results for a mean‐field model of systemic financial risk highlight the efficiency and accuracy of our estimator.     

审计质量、产权性质对上市公司投资效率的影响研究

审计质量作为第三方会计师事务所为公司提供的服务,可以独立于公司之外对上市公司投资活动进行监督。根据产权理论,产权性质不同的经济组织从事的经济活动不同,审计质量对不同产权性质的上市公司投资效率的影响也不相同。本文以2014—2018年沪深两市上市公司作为样本,实证检验了审计质量、产权性质与公司投资效率间的关系。研究发现,审计质量与上市公司投资过度显著负相关,与投资不足负相关但作用并不明显;在国有上市公司中审计质量对投资过度行为的抑制作用更明显,在非国有上市公司中审计质量可以在一定程度上防止投资不足行为的发生但作用并不显著。研究结论有利于启示各不同产权性质公司的利益相关方,客观认识审计师的作用功能及其局限性,有针对性、有效率地利用好审计服务,改善公司投资效率。