As investors squabble over when the Federal Reserve might lift short-term interest rates, central bankers meeting in Wyoming this week are likely to be debating what they might do if a future downturn forces them to put monetary policy into reverse.

就在投资者为美联储(Fed)可能何时上调短期利率争论不休时，本周将在美国怀俄明州召开会议的全球央行官员可能会讨论，如果未来经济衰退迫使他们逆转货币政策，他们该怎么办。

Policymakers will meet at the mountain resort of Jackson Hole amid concerns that central banks’ recession-fighting firepower is thin, and that an overhaul may be needed for how authorities steer their way through the economic cycle.

政策制定者将在杰克逊霍尔(Jackson Hole)避暑山庄召开会议，此时各界正在担心全球各央行抗击衰退的火力薄弱，各国当局可能需要彻底改变带领本国渡过经济周期的策略。

Last week John Williams, the president of the San Francisco Fed, floated reform ideas that challenged some of the basic assumptions of the central banking tribe. Among his suggestions was the idea of aiming for a higher inflation target to boost central banks’ room for manoeuvre when a downturn strikes.

上周，旧金山联邦储备银行(San Francisco Fed)行长约翰•威廉姆斯(John Williams)提出的改革想法，对央行界的部分基本假设构成挑战。其中一条建议是，设定更高的通胀目标，以使央行在衰退来袭时拥有更大的回旋余地。

Mr Williams was not calling for changes anytime soon, but the reason for his suggestion was clear. Eight years after the crisis, an unprecedented cascade of monetary stimulus has still left many leading economies nursing pedestrian growth rates and sluggish inflation. With rates at or close to the floor, there is little or no room for further cuts to spur growth.

威廉姆斯并不是呼吁短期内改变通胀目标，但是他提出该建议的原因是显而易见的。距离金融危机爆发已经8年之久，尽管推出了空前规模的货币刺激，很多领先经济体仍然徘徊于乏善可陈的经济增长率和低迷的通胀。在利率处于或接近下限的情况下，几乎不存在进一步降息来刺激增长的空间。

“This debate is really about the next recession and how much room there will be to act against it,” says Donald Kohn, a former vice-chairman of the Federal Reserve Board who is now at Brookings. “We do need a further rethink about how much scope central banks have to ease.”

“这场辩论实际是关于下次衰退以及我们拥有多少政策空间抵御衰退，”美联储前副主席、现就职于布鲁金斯学会(Brookings Institution)的唐纳德•科恩(Donald Kohn)表示，“我们确实需要进一步反思央行有多大的宽松政策空间。”

Policymakers are uneasy because of evidence that the so-called neutral rate of interest — the rate that is consistent with an economy operating on an even keel — is stuck at deeply depressed levels. The possible drivers for this decline include puny productivity growth, population ageing, and a glut of worldwide savings. The phenomenon is being seen across a number of large economies, among them the US, Canada, the euro area and the UK.

政策制定者感到惴惴不安是因为，证据显示所谓的中性利率（经济以趋势增长率增长、通胀稳定时的利率）陷在严重偏低水平。造成中性利率下降的可能原因包括：微弱的生产率增长、人口老龄化、以及全球储蓄过剩。这种现象已经在许多大型经济体出现，其中包括美国、加拿大、欧元区和英国。

With neutral rates on the floor, central banks are left with a shrinking degree of influence over the economy. They can slow activity by lifting policy rates, but there is little scope for stimulus via cuts. Tim Duy, a professor of economics at the University of Oregon, says: “Central banks appear to lack the ability by themselves to guide activity as much as they need to.”

在中性利率极低的情况下，央行对经济的影响力也会缩水。它们可以通过上调政策利率抑制经济活动，但是却没什么空间通过降息刺激经济。俄勒冈大学(University of Oregon)的经济学教授蒂姆•杜伊(Tim Duy)表示：“央行似乎缺乏引导经济活动的必要能力。”

Central bankers insist they have more tools at their disposal than some claim. In Europe and Japan central banks are experimenting with negative rates as well as asset purchases as they look for ways to ease further. The Bank of England has been spurred by Brexit in to launching a stimulus effort via a rate cut and new asset purchases.

央行官员坚称，他们拥有比一些人所声称的更多的工具。在欧洲和日本，央行正在试验负利率以及资产购买计划，寻找进一步放宽货币的方式。英国央行(BoE)受到英国退欧的刺激，以降息和新的资产购买计划推出了刺激措施。

A recent paper from the Federal Reserve Board argued that deploying rate cuts, asset purchases and forward guidance together could be even more effective than a hypothetical scenario where the central bank could cut rates as deeply into negative territory as it wanted rather than being constrained by the zero lower bound.

美联储最近一份报告认为，相比央行能够不受零利率下限的限制、在负值区间任意下调利率的假想情况，同时采取降息、资产购买和前瞻性指引的措施可能更加有效。

Nevertheless, the appeal of shooting for higher inflation is that it implies higher longer term interest rates and therefore more rate-cutting firepower when a downturn strikes. Joseph Gagnon, a former Fed economist now at the Peterson Institute for International Economics, says it is a notion whose time has come.

然而，以更高通胀率为目标的吸引力在于，它意味着更高的较长期利率，因此可以在衰退袭来时拥有更多的降息火力。前美联储经济学家、现在就职于彼得森国际经济研究所(Peterson Institute for International Economics)的约瑟夫•加尼翁(Joseph Gagnon)表示，这种理念的时代已经到来。

“If you had gone into the recession with 4 per cent inflation not 2 per cent then the whole structure of interest rates would have been higher,” he says.

“如果你在通胀率处于4%、而非2%的情况下进入衰退，那么整个利率结构都会更高，”他说。

Raising the inflation target is not, however, a “slam-dunk” policy change, Mr Kohn argues. Moving to a 3 per cent inflation target would require a “very serious conversation with Congress” over whether it met the definition of price stability in the Fed’s legislation, for instance.

然而，科恩认为，上调通胀目标不是“稳操胜券”的政策变动。例如，把通胀目标调至3%，需要就该目标是否满足美联储规定中有关价格稳定的定义“与国会进行非常严肃的对话”。

In addition, some costs might be hard to quantify. Former Fed chairs Alan Greenspan and Paul Volcker used to define price stability as the rate where households and businesses do not have to pay attention to inflation. “Two per cent might be on the edge, but 3 per cent might be over it,” he said.

此外，相关代价可能难以量化。前美联储主席艾伦•格林斯潘(Alan Greenspan)及保罗•沃克尔(Paul Volcker)曾经把价格稳定定义为家庭和企业无需关注通胀的通胀水平。“2%或许接近极限，但是3%可能就太高了，”他说。

If it lifted the inflation target, a central bank would then need to prove to the markets it could actually engineer an acceleration in price growth to that new goal. If it failed it would undermine credibility.

如果上调了通胀目标，那么央行将需要向市场证明，它确实有能力推动物价加速上涨，直至实现新目标。如果未能实现通胀目标，将有损央行的信誉。

Some economists argue more heavy lifting will need to be done by the fiscal authorities in future downturns, rather than central banks. Mr Duy, for example, is in favour of a higher inflation target or alternatively a nominal gross domestic product target, but he also says that in the US new “automatic stabilisers” are needed in budget plans to support the economy during a downturn.

一些经济学家认为，在未来出现衰退时，财政部门、而不是央行需要挑起更多重任。例如，杜伊支持上调通胀目标或名义国内生产总值(GDP)目标，但是他还表示，美国需要在预算计划中加入新的“自动稳定器”，在衰退时支撑经济。

The trouble is that proposals that led to bigger budget deficits in a downturn would likely founder in the face of sceptical Republicans on Capitol Hill — just like proposals for central banks to pursue higher inflation.

问题是，会在衰退到来时加大预算赤字的提议，在持怀疑态度的共和党议员面前很可能失败，就像允许央行上调通胀目标的提议一样。

For the time being, the path-breaking ideas being discussed by central bankers are likely to remain stuck in the realm of theory.

目前，央行家正在讨论的开创性想法可能仍将被困在理论领域。