長期停滯論”過時了?

A year ago, Lawrence Summers’ perceptive warnings about the possibility of secular stagnation in the world economy were dominating global markets. China, Japan and the Eurozone were in deflation, and the US was being dragged into the mess by the rising dollar. Global recession risks were elevated, and commodity prices continued to fall. Fixed investment had slumped. Productivity growth and demographic growth looked to be increasingly anemic everywhere.

一年前，勞倫斯?薩默斯(Lawrence Summers)有關世界經濟可能陷入長期停滯的有洞察力的警告主導着全球市場。那時，中國、日本和歐元區都處於通縮狀態，而美元升值把美國也拖入這個亂局。全球經濟衰退風險升高了，大宗商品價格持續下跌。固定投資大幅減少。在全球各地，生產率增長和人口增長似乎越來越疲弱。

Estimates of the equilibrium real interest rate in many economies were being marked down. It seemed possible that the world economy would fall into a “Japanese trap”, in which nominal interest rates would be permanently stuck at the zero lower bound, and would therefore not be able to fall enough to stimulate economic activity.

許多經濟體的均衡實際利率的預測值開始被調低。世界經濟看來有可能陷入“日本陷阱”——名義利率將永遠停留在底部爲零的極低區間，因此沒有進一步下調以刺激經濟活動的空間。

Just when the sky seemed to be at its darkest, the outlook suddenly began to improve. Global reflation replaced secular stagnation as the theme that dominated investor psychology, especially after Donald Trump’s election in November. Why has secular stagnation lost its mass appeal, and has it disappeared forever? Was it all a case of crying wolf?

就在局勢似乎最糟糕之際，前景突然開始改善。全球再通脹取代了長期停滯，成爲主宰投資者心理的主題，特別是在去年11月唐納德?特朗普(Donald Trump)勝選之後。爲什麼長期停滯失去了大衆吸引力，它永遠消失了嗎？當初有關它的說法是“狼來了”故事重演嗎？

Lawrence Summers has always made it clear that in his mind secular stagnation was a hypothesis, not a proven reality, especially in the US. He and others have argued that the combination of very low global GDP growth, alongside falling real interest rates, could be caused by two factors: (i) inadequate global demand, stemming from low business investment, high savings rates in Asia, wide disparity in income distribution and rising risk aversion; and (ii) inadequate global supply, stemming from falling productivity growth, and slowing growth in the labour force.

薩默斯始終明確表示，長期停滯只是他心裏的一種假設，而非已被證明的現實，尤其是在美國。他和其他人辯稱，全球GDP增長非常低，加上實際利率下降，這一組合可能是由兩個因素造成的：（1）企業投資水平低、亞洲儲蓄率高、收入分配不均嚴重和避險情緒升高導致的全球需求不足；以及（2）生產率增長減速和勞動力總數增長放緩帶來的全球供應不足。

With fears of deflation on the increase until early in 2016, it seemed that the weakness in demand was the more powerful force, although there was plenty of evidence of slowing growth in supply as well. Since inadequate demand growth seemed to be the main problem, and since the efficacy of monetary stimulus was being widely questioned, those economists who believed in secular stagnation frequently argued that fiscal stimulus was needed to rectify the problem.

在2016年初之前，人們對通縮的擔心日益加劇；有鑑於此，需求疲軟似乎是更爲強大的力量，儘管也有大量證據表明供應增長在放緩。由於需求增長乏力似乎是主要問題，由於貨幣刺激的效果受到廣泛質疑，那些相信長期停滯的經濟學家經常主張，需要財政刺激來糾正這個問題。

What has happened since to change the market’s level of concern about secular stagnation? The flow of incoming economic data has clearly changed a lot, as shown in our monthly update of the Fulcrum nowcast models, attached here.

後來發生的什麼事情改變了市場對長期停滯的擔憂？陸續發佈的經濟數據顯然發生了很大變化，正如本文隨附的每月更新的支點(Fulcrum)短時預測模型所顯示的那樣。

Global activity growth has rebounded sharply, and recession risks have plummeted. Growth in real output is now running at higher levels than anything seen since the temporary rebound from the financial crash in 2009/10. Importantly, recent data suggest that the growth rate of fixed investment is beginning to recover, which is a body blow to one of the central tenets of the secular stagnation school, though much of this may simply be due the end of the slump in the commodity sector.

全球活動增長已大幅反彈，經濟衰退風險已直線下降。目前實際產出的增速高於自金融危機之後2009/10年短暫反彈以來的任何時候。重要的是，近期數據似乎表明，固定投資的增幅開始回升——這對“長期停滯論”的核心依據之一構成了沉重打擊——儘管這一局面在很大程度上可能只是因爲大宗商品行業低迷的結束。

This recovery in real activity has not yet led to any rebound in long run underlying growth, according to the models. There has been no improvement in the growth of the labour force, and little rise in labour productivity growth, in the advanced economies in the last year. It therefore seems reasonable to conclude that the vast majority of the rise in real output growth has been due to improving aggregate demand, not aggregate supply.

模型預測顯示，實際經濟活動的復甦還沒有帶來長期潛在增長率的任何反彈。去年，在發達經濟體中，勞動力增長並未出現起色，生產率也幾乎未見上升。因此，我們似乎有理由得出這樣的結論：實際產出增長的加快在很大程度上來源於總需求（而非總供給）的改善。

The conclusion that global data have improved because of demand factors is also supported by the rise in inflation expectations that has occurred in all the main economies in the past 12 months. The increases in US and UK inflation expectations are not surprising, since both of these economies are operating very close to full employment. But the increases in Japan and the Eurozone are more impressive. These were the two economies that seemed to be completely stuck in secular stagnation due to excess capacity a year ago. Now, they seem to be escaping.

有關全球數據的改善緣於需求因素的結論，還得到過去12個月所有主要經濟體通脹預期上升的支持。美國和英國通脹預期上升並不奇怪，因爲這兩個經濟體目前都非常接近充分就業，但日本和歐元區的通脹預期上揚更令人印象深刻。這兩個經濟體一年前還貌似因產能過剩而深陷長期停滯，而現在它們似乎在擺脫停滯。

Up to a point, these escapes seem to be due to the success of macro-economic policies that were aimed to correct secular stagnation. The Fed postponed its plan to raise interest rates, so US short rates are about 75 basis points below the levels threatened a year ago. The Bank of Japan introduced a 10 basis points ceiling on 10 year government bond yields, an initiative that has appeared more successful than some of its earlier efforts to stimulate the economy. The ECB maintained and extended its programme of quantitative easing, and this has succeeded in normalising monetary conditions throughout the euro area.

在某種程度上，擺脫停滯似乎應該歸因於旨在糾正長期停滯的宏觀經濟政策取得成功。美聯儲(Fed)推遲了加息計劃，所以美國短期利率比一年前威脅要達到的水平低了約75個基點。日本央行(Bank of Japan)對10年期政府債券收益率提出10個基點的上限，這一舉措似乎比該行早前一些經濟刺激措施更加成功。歐洲央行(ECB)維持並延長了量化寬鬆計劃，此舉成功地讓整個歐元區的貨幣狀況正常化。

On fiscal policy, the changes were not huge, but they were definitely in the direction of expansion. According to the IMF, the stance of fiscal policy in the advanced economies in 2016 was 0.7 percent of GDP more stimulatory than planned a year ago. Furthermore, the election of Donald Trump greatly increased expectations of future easing in US fiscal policy, boosting business and household optimism about growth prospects.

財政政策方面的變化並不巨大，但肯定是向着擴張的方向改變。據國際貨幣基金組織(IMF)估算，2016年發達經濟體的財政政策姿態比一年前規劃的水平更具刺激效果，兩者之差相當於GDP的0.7%。此外，唐納德?特朗普當選大大增加了人們對於未來美國放寬財政政策的預期，促進了企業和家庭對增長前景的樂觀情緒。

All this suggests that stimulatory macro-economic policy may finally be working and that the secular stagnation scare might now be over. But that is probably too optimistic. Although there has been a cyclical improvement in demand in the advanced economies, there is no reason yet to believe that the supply side of the global economy is performing any better than it was a year ago. The secular speed limit on growth in the advanced economies is still much lower than it was in earlier decades. This speed limit has yet to be seriously tested but that may happen soon in the US and the UK.

所有這些都似乎表明，刺激性的宏觀經濟政策可能終於起了作用，長期停滯恐慌現在或許已經結束。但這麼想很可能太樂觀了。雖然發達經濟體的需求出現週期性改善，但沒有理由認爲全球經濟供給側的表現比一年前有任何提高。發達經濟體增長速度的長期限制仍遠低於幾十年前。這一速度限制尚未經過嚴格測試，但可能很快就會在美國和英國經受測試。

In any case, the recent spurt in growth in the advanced economies may turn out to be another false dawn, rather than the achievement of “escape velocity”. Even if escape velocity is achieved, and proves sustainable, it would need to prove that it can be maintained in the face of the policy tightening that would surely follow.

無論如何，發達經濟體近期的快速增長可能是又一個虛假的黎明，而不是達到了“逃逸速度”。即使達到了逃逸速度，而且被證明是可持續的，也還需要證明在面對肯定會接踵而來的政策收緊時，可以維持這一速度。

Last week, the President of the San Fancisco Fed, John Williams, released a paper on the decline in the equilibrium real interest rate in the US (r*), the concept that has been at the heart of the secular stagnation debate. This paper concluded that low r-star is a global phenomenon, is likely to be very persistent, and is not confined only to safe assets.

上週，舊金山聯邦儲備銀行(San Francisco Fed)行長約翰?威廉斯(John Williams)就美國均衡實際利率下降發表了論文，這個概念處於長期停滯辯論的核心。這篇文章的結論是，均衡實際利率較低是一個全球現象，可能會非常持久，而且不僅限於安全資產。

In other words, a cyclical recovery in demand, especially if confined mainly to the US, is unlikely to banish the problem of secular stagnation for very long.

換句話說，需求的週期性復甦（特別是如果主要限於美國），不太可能長久地消除長期停滯問題。

Gavyn Davies is a macroeconomist who is now chairman of Fulcrum Asset Management and co-founder of Prisma Capital Partners. He was the head of the global economics department at Goldman Sachs from 1987-2001, and was chairman of the BBC from 2001-2004.

加文?戴維斯(Gavyn Davies)是一位宏觀經濟學家，現任支點資產管理公司(Fulcrum Asset Management)董事長，他還是Prisma Capital Partners聯合創始人。他於1987年至2001年在高盛(Goldman Sachs)全球經濟部門擔任負責人，2001年至2004年在英國廣播公司(BBC)擔任董事長。