英语翻译There are good reasons why global analysis of NTBs acros

英语翻译
There are good reasons why global analysis of NTBs across sectors and countries is missing.
Under a common denomination NTBs regroup a vast array of potentially trade distorting policy
instruments.The UNCTAD classification of NTBs,the Trade Control Measures Coding System
identifies at its most detailed level over 100 instruments grouped in six categories.Unlike tariffs,NTBs are not straightforwardly quantifiable,not necessarily easy to model,and information about them is hard to collect.
It should therefore be no surprise that the modelling of NTBs using general equilibrium modelling techniques is still in its early stages.Except for subsidies in agriculture,little general
equilibrium work has been carried out on addressing the economics of NTBs either theoretically
or empirically.The study of NTBs creates sizeable challenges for an empirical exercise that relies
on vast and globally coherent datasets,and very often on strong assumptions.This means that ex
ante we know relatively little of the costs and benefits of NTBs.
Thanks to advances in computer and simulation technology,such as GTAP (Hertel,1997),and efforts to improve data collection and availability (TRAINS being a leading example),CGEsimulations of tariff reductions can nowalmost routinely be carried out.General equilibrium modelling has played an important role in the WTO multilateral negotiations,helping assess complex negotiation modalities and global interdependencies (e.g.Harrison,Tarr,& Rutherford,1996;Francois,van Meijl,& van Tongeren,2005; Anderson,Martin,& van der Mensbrugghe (2006);Polaski,2006),but also fuelling a public debate on the direction and magnitude of estimates.The same cannot be said of NTBs:we therefore propose in this paper to shift the discussion of modelling issues from tariffs to NTBs.We hope to contribute to the limited body of literature on CGE simulations of NTBs by testing various approaches to modelling of global NTB liberalisation.To our knowledge,this work is the first to offer a truly global and detailed assessmentof NTBs in a CGE model,using recent econometric estimates of NTBs ad valorem equivalents(AVEs) computed by Kee,Nicita,and Olarreaga (2006).We follow the path opened by the work of Andriamananjara et al.(2004),but which was limited to a subset of sectors.

全球范围内对于跨国与跨产业非关税贸易壁垒的研究和分析存在着缺失,这是有充分原因的.
在非关税贸易壁垒这一统一称谓下,集合了大量对正常贸易存在潜在威胁的政策工具.作为贸易管制措施编码系统,联合国贸发会议非关税贸易壁垒分类数据库可以对六大类一百多种此类政策工具进行精确识别.和关税不同,非关税贸易壁垒存在着不可直接量化,不易建模和难以收集其信息的问题.因此,采用普通均衡建模技术对其进行建模的研究仍处于初级阶段,也就不足为奇了.除了对农业的补贴,一般均衡研究不管在理论上还是经验上都几乎没有解决任何非关税贸易壁垒的经济学问题.对于非关税贸易壁垒的研究对建立在大量全球一致数据库基础上和经常依靠假设所建立起来的经验exercise构成了很大的挑战.这就意味着之前我们对非关税贸易壁垒的成本和益处知之较少.
由于计算机和模拟技术的进步,诸如如全球贸易分析项目（赫特尔,1997年）以及为改进数据收集和可用性的所作的努力（主要例子如TRAINS）,对关税削减的一般均衡模型模拟现在几乎可以定期举行.一般均衡模拟在世界贸易组织多边谈判中发挥了很重要的作用,帮助评估复杂的谈判模式和全球相互依存关系（括号内不确定）的同时,也加剧了公众对于评估的方向和评估量的争论.但对于非关税贸易壁垒情况就不一样了：因此我们在这里提议将对于建模问题的讨论从关税上转移到非关税贸易壁垒上.我们通过对全球非关税贸易壁垒自由化各种建模方法的测试,希望能为非关税贸易壁垒的一般均衡模型模拟的有限研究做出贡献.据我们所知,此文是第一个采用Kee, Nicita 和Olarreaga所确立的计量经济学评估方法---从价税等值法对非关税贸易壁垒一般均衡模型进行真正意义上全球和全面详细评估的.Andriamananjara所作的工作为我们的研究开辟了先河,但他当时的研究仅限于几个部门的子集.