全球央行會議面臨的難解之題

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.

就在投資者爲美聯儲(Fed)可能何時上調短期利率爭論不休時，本週將在美國懷俄明州召開會議的全球央行官員可能會討論，如果未來經濟衰退迫使他們逆轉貨幣政策，他們該怎麼辦。

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.

政策制定者將在傑克遜霍爾(Jackson Hole)避暑山莊召開會議，此時各界正在擔心全球各央行抗擊衰退的火力薄弱，各國當局可能需要徹底改變帶領本國渡過經濟週期的策略。

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.

上週，舊金山聯邦儲備銀行(San Francisco Fed)行長約翰•威廉姆斯(John Williams)提出的改革想法，對央行界的部分基本假設構成挑戰。其中一條建議是，設定更高的通脹目標，以使央行在衰退來襲時擁有更大的迴旋餘地。

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.

威廉姆斯並不是呼籲短期內改變通脹目標，但是他提出該建議的原因是顯而易見的。距離金融危機爆發已經8年之久，儘管推出了空前規模的貨幣刺激，很多領先經濟體仍然徘徊於乏善可陳的經濟增長率和低迷的通脹。在利率處於或接近下限的情況下，幾乎不存在進一步降息來刺激增長的空間。

“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.”

“這場辯論實際是關於下次衰退以及我們擁有多少政策空間抵禦衰退，”美聯儲前副主席、現就職於布魯金斯學會(Brookings Institution)的唐納德•科恩(Donald Kohn)表示，“我們確實需要進一步反思央行有多大的寬鬆政策空間。”

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爲，證據顯示所謂的中性利率（經濟以趨勢增長率增長、通脹穩定時的利率）陷在嚴重偏低水平。造成中性利率下降的可能原因包括：微弱的生產率增長、人口老齡化、以及全球儲蓄過剩。這種現象已經在許多大型經濟體出現，其中包括美國、加拿大、歐元區和英國。

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.”

在中性利率極低的情況下，央行對經濟的影響力也會縮水。它們可以通過上調政策利率抑制經濟活動，但是卻沒什麼空間通過降息刺激經濟。俄勒岡大學(University of Oregon)的經濟學教授蒂姆•杜伊(Tim Duy)表示：“央行似乎缺乏引導經濟活動的必要能力。”

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.

央行官員堅稱，他們擁有比一些人所聲稱的更多的工具。在歐洲和日本，央行正在試驗負利率以及資產購買計劃，尋找進一步放寬貨幣的方式。英國央行(BoE)受到英國退歐的刺激，以降息和新的資產購買計劃推出了刺激措施。

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.

美聯儲最近一份報告認爲，相比央行能夠不受零利率下限的限制、在負值區間任意下調利率的假想情況，同時採取降息、資產購買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，以更高通脹率爲目標的吸引力在於，它意味着更高的較長期利率，因此可以在衰退襲來時擁有更多的降息火力。前美聯儲經濟學家、現在就職於彼得森國際經濟研究所(Peterson Institute for International Economics)的約瑟夫•加尼翁(Joseph Gagnon)表示，這種理念的時代已經到來。

“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.

“如果你在通脹率處於4%、而非2%的情況下進入衰退，那麼整個利率結構都會更高，”他說。

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，科恩認爲，上調通脹目標不是“穩操勝券”的政策變動。例如，把通脹目標調至3%，需要就該目標是否滿足美聯儲規定中有關價格穩定的定義“與國會進行非常嚴肅的對話”。

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，相關代價可能難以量化。前美聯儲主席艾倫•格林斯潘(Alan Greenspan)及保羅•沃克爾(Paul Volcker)曾經把價格穩定定義爲家庭和企業無需關注通脹的通脹水平。“2%或許接近極限，但是3%可能就太高了，”他說。

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.

如果上調了通脹目標，那麼央行將需要向市場證明，它確實有能力推動物價加速上漲，直至實現新目標。如果未能實現通脹目標，將有損央行的信譽。

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.

一些經濟學家認爲，在未來出現衰退時，財政部門、而不是央行需要挑起更多重任。例如，杜伊支持上調通脹目標或名義國內生產總值(GDP)目標，但是他還表示，美國需要在預算計劃中加入新的“自動穩定器”，在衰退時支撐經濟。

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.

問題是，會在衰退到來時加大預算赤字的提議，在持懷疑態度的共和黨議員面前很可能失敗，就像允許央行上調通脹目標的提議一樣。

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，央行家正在討論的開創性想法可能仍將被困在理論領域。