Free exchange: Moral hazard 自由交流：道德风险

　　Economists cannot avoid making value judgments, however much they might wish to. 经济学家无法避免作出价值判断, 不管他们可能多想避免。

　　AMID the name-calling and bluster that mar many fights between economists are a few common tactics. 在让经济学家间的许多论战变得污浊不堪的谩骂恫吓之中，有一些常见的策略。

　　Belligerents may attack the theory used to support a claim, or the data analysis used to quantify an effect. 交战双方可能攻击某种理论被用来支持一种诉求，或者是某种数据分析被用来量化一种效应。

　　During the debate over President Donald Trump's tax bill, to take a recent example, economists bickered over which side had more credibly calculated the economic effect. 拿最近的一个例子来说，在有关特朗普税法的争论期间，经济学家围绕着哪一方更加可信地核算了经济效应展开了论战。

　　They did not, for the most part, argue about whether it was morally acceptable to pass a regressive tax reform after years of wage stagnation and rising inequality. 他们大都没有论及在数年的工资停滞和日渐加剧的不平等之后，通过一项累退的税收改革在道德方面是否可以接受。

　　To do so would strike many economists as entirely un-economist-like. Yet economics has not always been so shy about moral philosophy.  这么做将会打击许多经济学家，使他们完全不像经济学家一样。经济学并不是一直对道德哲学如此害羞。

　　As well as “The Wealth of Nations”, Adam Smith wrote a “Theory of Moral Sentiments”.  除了《国富论》，亚当斯密还写了《道德情操论》。

　　Great 20th-century economists like Paul Samuelson and Kenneth Arrow also took questions of values very seriously.  像保罗·萨缪尔森和肯尼斯·阿罗等20世界伟大的经济学家们也非常认真地对待价值观问题。

　　Their successors would do well to take several pages from their books. 其继承者们最好从他们的著作中拿出几页。

　　Modern economists have attempted to strip value-judgments out of their policy analyses.  现代经济学家试图从其政策分析中剔除价值判断。

　　Policies are judged on how they are likely to affect economic variables such as income and its distribution, and how those changes would affect overall welfare.  政策是根据它们如何可能影响诸如收入及其分配等经济变量而判断的，也是根据这些变化如何影响整体福利而判断的。

　　If the models suggest that one policy choice—a top tax rate of 40%, say, rather than 50%—leads to greater welfare than another, that is usually good enough for an economist. 如果模型表明，一项政策选择的——比如，最高税率40%，而不是50%——这就会带来比另一种税率更高的福利，这对经济学家来说通常是足够好的。