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[经济学人] [2008.06.12]Control freaks 控制狂

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发表于 2010-4-29 03:50 | 显示全部楼层 |阅读模式
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Control freaks
Jun 12th 2008

From The Economist print edition

Are “randomised evaluations” a better way of doing aid and development policy?
“随机评估”会是一个做援助和发展政策更好的方法吗?

Illustration by Jac Depczyk



DOCTORS study diseases from several vantage points. Laboratory scientists peer into microscopes to observe the behaviour of bugs. Epidemiologists track sickness in populations. Drug-company researchers run clinical trials. Economists have traditionally had a smaller toolkit. When studying growth, they put individual countries under the microscope or conduct cross-country macroeconomic studies (a bit like epidemiology). But they had nothing like drug trials. Economic data were based on observation and modelling, not controlled experiment.

医生通过多方面的有利位置研究疾病,科学家通过显微镜观察生物的行为,流行病学家在人群中跟踪疾病,医药公司的研究人员则可以做临床试验。而传统的经济学家曾经能使用的研究工具就要少得多了。当研究经济增长时,他们观察单个国家或者做跨国的宏观经济研究(有点像流行经济学家),但他们无法做像药物试验一样的经济学实验。经济数据以观察和模型化为基础,而不是可控的实验。

That is changing. A tribe of economists, most from Harvard University and the Massachusetts Institute of Technology (MIT), have begun to champion the latest thing in development economics: “randomised evaluations” in which different policies—to boost school attendance, say—are tested by randomly assigning them to different groups. In one celebrated example, researchers looked at what happened in 20 antenatal clinics in western Kenya when some gave away insecticide-treated bednets, an anti-malaria therapy, and others sold them for different prices. Their conclusion was that free distribution is far more effective in getting people to use bednets than charging even a nominal sum would be.

但不过现在不是这样了,一伙儿主要来自哈佛大学和麻省理工学院的经济学家开始拥护发展经济学中的一个新概念:“随机评估”,即将不同的政策随机分配于不同的群体进行实验。一个著名的例子是,研究人员对肯尼亚西部20个产前检查诊所对的蚊帐(经驱蚊处理的蚊帐,这是一种对抗疟疾的方法)发放行为及结果进行观察,其中一部分诊所免费发放蚊帐,另一些诊所则通过不同的价格出售蚊帐。他们结论是在促进人们使用蚊帐方面,免费发放比哪怕是只收取一点象征性费用的效果都要好。


Such trials are not unprecedented in economics. America's welfare reform of 1996 was based partly on controlled experiments. But they have been rare enough for today's upsurge to count as a revolution in thinking about development. Last year the Spanish government gave the World Bank $16m—the institution's largest trust fund—to spend on evaluating projects. The fund's first criterion calls for randomised trials. This will spread their influence further.
这样的实验在经济学界并非没有先例。1996美国福利改革便是部分地基于可控的实验。但比起今天。去年,西班牙政府支付给世界银行1600万美元用于项目评估,这是该机构最大的信托基金了。该基金的第一条标准就是要求做随机试验。这将扩大随机试验的影响力。

   But are such trials all they are cracked up to be? Randomistas recently gathered at the Brookings Institution, a think-tank in Washington, DC, to discuss that.*  但是这些试验真的如它们被赞扬的那样吗?随机主义者最近在Brookings研究所(位于华盛顿的一个智库)聚集,讨论此问题。

   Randomised evaluations are a good way to answer microeconomic questions such as how to get girls to go to school, and teachers to turn up for work. They cannot tell you much about macro questions like the right exchange-rate or budget policy. But often, they provide information that could be got in no other way. To take bednets: supporters of distributing free benefits say that only this approach can spread the use of nets quickly enough to eradicate malaria. Supporters of charging retort that cost-sharing is necessary to establish a reliable system of supply and because people value what they pay for. Both ideas sound plausible and there was no way of telling in advance who was right. But the trial clearly showed how people behave.  随机评估能很好的回答一些微观经济学问题,比如如何让女孩去上学,让老师去上班。但在回答宏观问题上并无优势,比如汇率或预算政策。但是随机评估常常能提供一些其它方式不能提供的信息。比如蚊帐的例子:免费发放的支持者认为这是能足够快速普及蚊帐使用并根除疟疾的唯一途径。收费出售的支持者则反驳认为费用分摊是建立可靠的供给体系的必要方式,并且人们会重视他们所付费购买的东西。两种看法听上去都貌似有理,也没有能预先判定谁对谁错的办法。但现在这个试验清楚地显示了人们反应。

   So evidence from randomised trials is good. But is it better than other economic data? That is what many randomistas believe. Abhijit Banerjee, the co-founder of the Abdul Latif Jameel Poverty Action Laboratory (J-PAL), argues that “the quality of the evidence that informs much of the macro-growth debates is significantly worse than the quality of the data that bears on many of the micro-policy questions”. He adds: “The beauty of randomised evaluations is that the results are what they are.” In other words, they provide hard evidence, resting on a solid empirical base. Aid and development policy, concludes Mr Banerjee, should take more account of that evidence.  随机试验得到数据还是蛮不错的,但是它真的会比其它经济数据更好吗?许多随机主义者相信是如此。Abdul Latif Jameel Poverty Action Laboratory的联合创立人Abhijit Banerjee认为宏观经济方面讨论所使用的证据的质量要明显的差于与微观政策相关的数据的质量。随机评估之美就在于结果的真实。换句话说,它依靠可靠经验主义基础,提供确凿的证据。Banerjee先生总结道:援助与发展政策应该多多考虑这些证据。

   But is the evidence really incontrovertible? On its own terms, yes. As Mr Banerjee says, the evidence is what it is. But policymakers do not want to know whether something works in a few villages. They want to know whether it will work nationwide. Here, randomised trials may not be quite so helpful.  但是这些证据真的就无可争议的吗?就其本身来说当然是,正如Banerjee先生说的,这些证据是“事实如此”的证据。但是政策制定者没有兴趣知道那些只在一些乡村起作用的东西,他们想知道在全国范围内是否能奏效。从这个角度讲,随机试验貌似就帮助不大了。

   Go back to the bednets once more. You might conclude that the trial showed that they should always be given away. Yet it turns out that millions of nets were already in use in the part of Kenya where the field trial took place, so their value was known. The experiment guaranteed supplies, so it did not test the assertion that you need to charge something to encourage reliable suppliers. And the recipients were pregnant women, whereas the point of giving bednets away is to provide anti-malaria treatment universally. The evidence from western Kenya was clear. But it hardly settled the question of whether the government should give bednets away across the country. Questions like that may still have to be made on the basis of the soft evidence that randomistas turn up their noses at.  再次回到蚊帐的例子。你可能认为试验蚊帐应该始终被免费发放。当然,已经有数以百万计的蚊帐在肯尼亚的试验区被使用,因此其价值是看得到的。但这个试验有充足的供应保证,因此关于需要收费以鼓励可靠供给的主张并没有在此试验中得到测试。并且蚊帐的接受者是孕妇,发放蚊帐的主要目的是为了普遍的提供抗疟疾的帮助。肯尼亚西部的证据是清楚的,但是是否应当在全国范围内免费发放蚊帐仍然是个难题。因为缺乏确凿的证据,类似的问题仍然会出现,这些不确凿的证据常被随机主义者嗤之以鼻。

   Randomistas rule?  随机主义者的时代到来了?

   Mr Banerjee doubts whether randomistas and other development economists will ever get along. The differences over research methods and what counts as evidence are too great. Economists do not know enough about growth, he says, to justify their obsession with it, however important it may be. Following the law of comparative advantage, they should do much more of what can be done best—randomised testing. Banerjee先生怀疑随机主义者和其它发展经济学者是否能友好相处。两者的研究方法以及对什么是证据的看法差异太大。Banerjee说,经济学者对经济增长的了解不够多,,。。。根据比较优势理论,他们应该做更多能够做好的事--即随机试验。


But given doubts about how widely applicable such tests are, it may be better to think of them not as a new, superior form of development economics but as one more technique—admittedly a useful one—for finding out what works, filling in gaps in knowledge, testing policy ideas, and puncturing conventional wisdom. Dani Rodrik of Harvard University argues that differences in research methods between randomistas and other economists are in danger of re-opening a split between macro- and micro-economists that is starting to heal. Over the past few years, he claims, both groups have converged on a more experimental approach to development, eschewing lists of standard prescriptions and stressing the importance of context. That approach may be bearing fruit. It would be a shame if triumphalist claims by randomistas were to limit their contribution to it.  随机试验到底能在多大范围适用?面对此疑问,我们最好别把它看作是一个新的、更优越的发展经济学形式,而应该把它当作一个技术含量更高的方法,它更有助于研究问题、填补知识空白、测试政策理念、推翻传统智慧。哈佛大学的Dani Rodrik认为随机主义者和其它经济学者在研究方法上的差异可能使经济学面临如下危险:即宏观和微观经济学者的割裂被重新打开,它本来才刚刚开始愈合。在过去几年,两大阵营聚合在更具实验性的研究方法上,他们抛开那些所谓的“标准药方”,强调约束坏境的重要性。这种研究方法或许能有所突破。。。。。。。。。

有下划线句子未翻译,请高手指教
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发表于 2010-4-29 04:00 | 显示全部楼层
来了,第一时间支持你!!
我看后,详细留言.
如有问题,你知道怎么找我~~
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发表于 2010-4-29 04:10 | 显示全部楼层
Economists do not know enough about growth, he says, to justify their obsession with it, however important it may be.
经济学家对增长缺乏了解,这将使得他们无法证明为人笃定的随机实验,将有怎样的重要性.
Following the law of comparative advantage, they should do much more of what can be done best—randomised testing.
但是基于比较优势理论,人们较过去所做的一切,所能做出的最好选择就是随机实验.
It would be a shame if triumphalist claims by randomistas were to limit their contribution to it.  
然而,可能令人遗憾的是,最终获得胜利的随机主义者被限制使用他们的研究成果.


表达和理解都提高不少,但是还要继续努力,原文有不少地方还不够流畅,建议多多润色.
没改太多,不想破坏原文朴实的风格.有时间,我重译这篇,我们讨论一下
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