This week’s news that US core inflation came in lower than expected in July has increased the likelihood that the US Federal Reserve will keep interest rates on hold for the rest of this year. True, there may be some boost in the form of inflation emanating from China, where producer prices have recently shown strength. But the Fed and other central banks face a structural predicament from which they will not escape via an increase in import prices.

这周传出的7月份美国核心通胀率低于预期的新闻，增加了美联储(Fed)在今年余下时间里保持利率不变的可能性。没错，源自中国的通胀也许会带来某种程度的提振——中国的生产者价格最近呈现出走强态势。但是，美联储和其他央行面临的结构性困境，是无法借助进口价格上涨逃脱的。

An apparent slow drift down in the natural rate of interest and trend growth across nations means a lower long-term level of policy rates, less room to cut during recessions and the need to resort to extraordinary and possibly distorting measures such as quantitative easing.

自然利率和各国趋势增长率似乎都在缓慢下滑，这意味着较低的长期政策利率水平、衰退期间更小的利率下调空间以及采取非常规且可能造成扭曲的措施（如量化宽松）的必要性。

John Williams, president of the San Francisco Federal Reserve, this week posited a solution: that the Fed might increase its inflation target, allowing the economy to run faster than otherwise and pushing interest rates higher. This would allow bigger cuts in rates during recessions.

旧金山联邦储备银行(San Francisco Fed)行长约翰•威廉斯(John Williams)本周设想了一种解决方案：美联储或许可以提高通胀目标，让经济得以增长得更快一些并推高利率。这样就会为衰退期间留下更大的利率下调空间。

Yet as a practical matter, it is hard to argue in the current conjuncture that the Fed is chafing against the constraints of its policy framework. The central bank has leeway it is choosing not to use. The 2 per cent inflation target did not force the Fed’s open market committee to raise interest rates in December last year for the first time since 2006. The increase was a purely unforced error, as would be another rate increase in the near future.

不过事实上，当前局面下很难说美联储已经触及其政策框架的极限。美联储还有政策余地，只是它选择不去动用而已。去年12月，美联储公开市场委员会(FOMC)自2006年以来首次加息，这一举动并不是迫于2%的通胀目标才做出的。那次加息纯粹是个在非被迫情况下发生的错误，假如美联储近期内再次加息，将重复这一错误。

The Fed’s main problem at the moment is not its framework, but overestimating inflationary pressure and underestimating the cost of yet more undershooting of its target. Raising the target is likely only to mean that the central bank misses it by more and thereby leaches credibility.

当前美联储的主要问题不是它的政策框架，而是高估通胀压力，低估与通胀目标差距扩大的代价。提高通胀目标可能仅仅意味着该行会在更大程度上低于这一目标，从而损失可信度。

If the Fed is to adjust its goal, it would make more sense to adopt another of Mr Williams’ suggestions and target a price level rather than an inflation rate, aiming to follow a period of inflation running below target by spending an equivalent time above it. That would encourage it to run the economy at a faster rate while avoiding a confusing change in the numerical target which, as Fed chair Janet Yellen said in a speech in September, would raise suspicions that the goalposts would be opportunistically moved again.

如果美联储要调整目标，那么更合理的做法是采纳威廉斯的另一条建议，盯住一个价格水平，而非通胀率，致力于让通胀在低于目标一段时期之后，接着在同样长的一段时期里高于目标。这将促使美联储让经济在更高速率上运行，同时避免在目标数字上进行令人困惑的更改，就如美联储主席珍妮特•耶伦(Janet Yellen)在去年9月的一次演讲中所说的，这种更改会让人怀疑，美联储未来会再次对目标做出带有机会主义意味的更改。

In any case, policymakers should be concentrating on hitting the current target, not talking about changing it. Holding central bankers solely responsible for inflation is part of the problem. Stable positive inflation comes when demand is bumping up against the economy’s output capacity. If central banks are struggling to generate such demand without extraordinary and potentially distortionary actions, it is up to finance ministries to do their part by stimulative fiscal policy.

在任何情况下，政策制定者都应该集中精力达到当前的目标，而不是考虑改变目标。一部分问题在于，让央行官员对通胀担负全部责任。稳定的正通胀是在需求扩大到触及经济产出能力的时候出现的。如果央行难以在不采取可能造成扭曲的非常规手段的情况下产生这样的需求，那么财政部就该发挥自己的作用，推出刺激性财政政策。

Although there have been a few signs of fiscal policy turning stimulative in the large advanced economies, they are a long way from accepting the full role that taxing and spending should have in boosting demand.

尽管在大型发达经济体，已经出现一些财政政策转向刺激经济的迹象，这些经济体还远没有接受这种做法，即让征税和支出在提振需求中发挥应有的全部作用。

Formally sharing responsibility for hitting an inflation target between monetary and fiscal policymakers is going too far: it would merely encourage blame-shifting. But central bankers could certainly be more open about the need for boosts from more public spending or tax cuts, or both, to help address the issue of chronically underperforming growth and low inflation.

让货币政策制定者和财政政策制定者正式地共担达到通胀目标的责任就过头了：这只会鼓励推卸责任。但央行银行家完全可以更公开地指出，需要更多公共支出或（和）减税来提振经济，以帮助解决长期增长低迷和低通胀的问题。

Mr Williams deserves credit for increasing the salience of the discussion about targets. Yet the immediate need is to use monetary and fiscal tools better within the existing framework, rather than to tinker with the workings of the system.

威廉斯让关于目标的这场讨论更受重视，这值得称许。但目前的迫切需求是，在现存框架下更好地利用货币工具和财政工具，而不是胡乱修改系统的运行机制。