The Price of Land and Houses falls;
Mirac’lous Palaces, whose Walls,
Like those of Thebes, were rais’d by Play
Are to be let; . . . .
The building Trade is quite destroy’d
Artificers are not employ’d; . . .
Those, that remain’d, grown temp’rate strive
Not how to spend, but how to live . . .
That sounds a lot like what many advanced countries have been going through, after financial-crisis-induced austerity plans were launched, doesn’t it? Is Mandeville a genuine prophet for our times?
Fable of the Bees developed a wide following, and generated substantial controversy, which continues to this day. The austerity plans being adopted by governments in much of Europe and elsewhere around the world, and the curtailment of consumption expenditure by individuals as well, threaten to produce a global recession.
But how do we know if Mandeville is right about austerity? His research method – a long poem about his theory – is hardly convincing to modern ears.
Harvard economist Alberto Alesina recently summarized evidence concerning whether government deficit reduction – that is, expenditure cuts and/or tax increases – always induces such negative effects: “The answer to this question is a loud no.” Sometimes, even often, economies prosper nicely after the government’s deficit is sharply reduced. Sometimes, just maybe, the austerity program boosts confidence in such a way as to ignite a recovery.
We have to examine the issue with some care, understanding that the issue that Mandeville raised is really a statistical one: the outcome of government deficit reduction is never entirely predictable, so we can ask only how likely such a plan is to succeed in restoring economic prosperity. And the biggest problem here is accounting for possible reverse causality.
For example, if evidence of future economic strength makes a government worry about economic overheating and inflation, it might try to cool domestic demand by raising taxes and lowering government spending. If the government is only partly successful in preventing economic overheating, it might nonetheless appear to casual observers that austerity actually strengthened the economy.
Likewise, the government’s deficit might fall not because of austerity, but because the stock market’s anticipation of economic growth fuels higher revenues from capital-gains tax. Once again, we would see what might appear, from looking at the government deficit, to be an austerity-to-prosperity scenario.
Jaime Guajardo, Daniel Leigh, and Andrea Pescatori of the International Monetary Fund recently studied austerity plans implemented by governments in 17 countries in the last 30 years. But their approach differed from that of previous researchers. They focused on the government’s intent, and looked at what officials actually said, not just at the pattern of public debt. They read budget speeches, reviewed stability programs, and even watched news interviews with government figures. They identified as austerity plans only those cases in which governments imposed tax hikes or spending cuts because they viewed it as a prudent policy with potential long-term benefits, not because they were responding to the short-term economic outlook and sought to reduce the risk of overheating.
Their analysis found a clear tendency for austerity programs to reduce consumption expenditure and weaken the economy. That conclusion, if valid, stands as a stern warning to policymakers today.
But critics, such as Valerie Ramey of the University of California at San Diego, think that Guajardo, Leigh, and Pescatori have not completely proven their case. It is possible, Ramey argues, that their results could reflect a different sort of reverse causality if governments are more likely to respond to high public-debt levels with austerity programs when they have reason to believe that economic conditions could make the debt burden especially worrisome.
That may seem unlikely – one would think that a bad economic outlook would incline governments to postpone, rather than accelerate, austerity measures. And, in response to her comments, the authors did try to account for the severity of the government’s debt problem as perceived by the markets at the time that the plans were implemented, finding very similar results. But Ramey could be right. One would then find that government spending cuts or tax hikes tend to be followed by bad economic times, even if the causality runs the other way.
Ultimately, the problem of judging austerity programs is that economists cannot run fully controlled experiments. When researchers tested Prozac on depressed patients, they divided their subjects randomly into control and experimental groups, and conducted many trials. We cannot do that with national debt.
So do we have to conclude that historical analysis teaches us no useful lessons? Do we have to return to the abstract reasoning of Mandeville and some of his successors, including John Maynard Keynes, who thought that there were reasons to expect that austerity would produce depressions?
There is no abstract theory that can predict how people will react to an austerity program. We have no alternative but to look at the historical evidence. And the evidence of Guajardo and his co-authors does show that deliberate government decisions to adopt austerity programs have tended to be followed by hard times.
Policymakers cannot afford to wait decades for economists to figure out a definitive answer, which may never be found at all. But, judging by the evidence that we have, austerity programs in Europe and elsewhere appear likely to yield disappointing results.
Robert Shiller, Professor of Economics at Yale
University,
is co-author, with George Akerlof, of Animal Spirits: How Human Psychology
Drives the Economy and Why It Matters for Global Capitalism.
Robert J. Shiller: 緊縮能推動經濟增長嗎？
荷蘭出生的英國哲學家兼諷刺作家伯納德·曼德維爾在其1724年出版的經典名著《蜜蜂的寓言：私人的惡德，公眾的利益》中用一首長詩來描述一個原本繁榮，卻突然選擇以節儉為美，放棄一切額外支出和奢侈消費的（蜜蜂）社會，詩文如下：
地價房價驟跌；
那些為享樂而建的，壯麗宮殿，
那些底比斯式的，雕梁鬥拱，
都要轉手；……
建築行業盡毀
營造者們也失了業；……
那些幸存者們，變得克己而勤奮
不為消費，只為生存……
在金融危機的影響下許多發達國家都啟動了緊縮政策，而這首詩的內容聽上去也與它們的近況極為相似——莫非曼德維爾才是預言我們這個時代的真正先知？
《蜜蜂的寓言》從出版至今依然擁有一大批追隨者並引發了大量的爭論。而歐洲大部分國家以及其他地區國家的政府所采用的緊縮政策以及個人消費支出的縮減，都可能導致一場全球性衰退。
但我們怎麼知道曼德維爾對於緊縮的判斷是對的？他的研究方法——一首闡述自身理論的長詩——往往難以令當今的人們信服。
哈佛大學經濟學家阿爾伯圖·阿里辛納（Alberto Alesina）最近總結了一些關於政府赤字縮減政策——即支出縮減和/或加稅——會否導致這類負面效應的證據：“對這個問題的答案是一個大大的‘不’字。”有時（甚至是經常性的），經濟會在政府大幅減少赤字後蓬勃發展；有時（但只在有可能的情況下），緊縮政策能以上述手段提振信心並激發復蘇。
我們必須謹慎地研究這個問題，並意識到曼德維爾所提到的狀況實際上是一個統計學上的現像：你永遠無法全面預測政府緊縮政策的結果，因此我們只能詢問這麼一個計劃成功推動經濟復蘇的可能性究竟有多大。而其中最重要的問題則是解釋可能存在的逆向因果關系。
比如說，如果某些與未來經濟相關的證據使某國政府擔心可能出現經濟過熱和通脹，它可能會嘗試通過加稅和降低政府支出來為國內需求降溫。即便這些防止過熱措施只取得了部分成功，但在普通旁觀者眼裡，這些緊縮政策似乎已經實質上增強了經濟。
同樣，政府的赤字不僅會因緊縮而下降，也可能是因為股票市場對經濟增長的預期帶來了更多資本利得稅收入。這一次我們可能也會從政府赤字的角度，認為是緊縮實現了繁榮。
而國際貨幣基金組織的賈米·瓜加爾多（Jaime Guajardo），丹尼爾·利（Daniel
Leigh）和安德烈·佩斯卡托利（Andrea Pescatori）最近研究了過去30年內17國政府所采取的緊縮政策。他們把焦點放在政府的動機之上，並研究政府官員們的言論，而不僅僅是公共債務的模式。他們研讀預算報告，檢討金融穩定政策，甚至觀看那些政府高官的新聞采訪。在他們的定義中，緊縮政策是那些政府將加稅或者削減支出視為一個將產生潛在長期收益的明智政策，而不是對短期經濟預測的回應或者嘗試減少經濟過熱的風險。
他們的研究發現緊縮政策具有減少消費支出並削弱經濟的明顯趨勢。這個結論如果是正確的話，那麼政策制定者們就要小心了。
但包括加州大學聖地亞哥分校經濟學教授維拉莉爾·拉梅（Valerie Ramey）在內的批評者則認為上述論證並不完整。拉梅認為上述研究結果可能只是反映了一個不同形式的逆向因果關系，因為政府之所以更可能用緊縮政策來應對高公共負債水平，就是因為它有理由相信經濟狀況將令債務負擔特別令人憂慮。
這看上去似乎不太可能——有人會認為一個悲觀的經濟預測將促使政府推遲（而不是加速）緊縮措施。同時為了回應她的評論，三位作者也確實嘗試對緊縮計劃推出時市場對政府債務問題嚴重性的預期進行了評估，並發現了類似的結果。當然拉梅也可能是對的。但即便順推這一因果關系，人們可能也會發現政府支出削減或者加稅之後會經歷一段不景氣時期。
最終，評判緊縮政策的問題在於經濟學家無法運行一個完全受控實驗。比如研究者們測試百憂解（一種抗抑郁藥物）的時候，他們可以把被試者隨機分為控制組和實驗組並反復測試。而在國家債務問題上顯然是無法做到這一點的。
因此我們是否就可以認為那些歷史分析並無教益？我們是否應該回到曼德維爾及其某些繼承者（包括凱恩斯）的抽像推理方式，認為有理由去預期緊縮政策將導致衰退？
沒有抽像理論能預測人們究竟將如何對一項緊縮政策做出反應。我們沒有選擇，只能回顧那些歷史證據。而賈米·瓜加爾多及其同僚所發現的證據也確實顯示政府深思熟慮後出台的緊縮政策後面往往會伴隨一段不景氣時期。
政策制定者們不可能有幾十年去等待經濟學家們找出一個確定的答案——而這個答案甚至永遠都無法得出。但根據我們目前的證據來判斷的話，歐洲以及其他地區的緊縮政策似乎將帶來令人失望的結果。
作者為耶魯大學經濟學教授，與George Akerlof合著有"Animal
Spirits: How Human Psychology Drives the Economy and Why It Matters for Global
Capitalism"一書。
