Why are the high-income countries not mired in deflation? This is the puzzle today, not the absence of the hyperinflation that hysterics have wrongly expected. It is weird that inflation has remained so stable, despite huge shortfalls in output, relative to pre-crisis trends, and prolonged high unemployment. Understanding why this is the case is important because the answer determines the correct policy action. Fortunately, the news is good. The stability of inflation seems to be a reward for the credibility of inflation targeting. That gives policy makers room to risk expansionary policies. Ironically, the success of inflation targeting has revitalised Keynesian macroeconomic stabilisation. A chapter in the latest World Economic Outlook from the International Monetary Fund presents the case for this encouraging conclusion, as has already been noted by, among others, Gavyn Davies and Paul Krugman. Its starting point is with the stickiness of inflation, despite the lengthy period of very high joblessness. Thus, states the IMF, “we find a dog that did not bark”. A possible explanation for this phenomenon is structural. It is argued by many, for example, that the workers who lost their jobs in construction and other bubble-era activities have the wrong skills or are located in the wrong places to take up the new jobs that might now – or soon – be on offer. Again, if unemployment is allowed to remain high for long, what starts as temporary joblessness is likely to become permanent, as workers lose the skills and networks that make it relatively easy to find jobs. So the duration of the Great Recession has put long-term joblessness near record levels. All this tends to make competition in labour markets weak. An alternative explanation is more encouraging. It is that inflation targeting has anchored expectations and so labour market behaviour. Moreover, these targets are close to zero. We know that workers are resistant to cuts in nominal wages. This has remained true throughout the Great Recession: it is indeed one of the reasons why the adjustment in the eurozone is so painful. So, for this reason too, inflation would be sticky, at least downwards. The chapter’s preliminary analysis of these alternatives reaches three main conclusions. The first is that “expectations are strongly anchored to the central banks’ inflation targets rather than being particularly affected by current inflation levels”. Second, the anchoring of expected inflation has increased over time, while the impact of current inflation on expected inflation has diminished. Finally, the relationship between inflation and current unemployment has correspondingly diminished. It became nearly non-existent after 1995, which saw a long period of stable inflation in line with the inflation targets of central banks. The detailed econometric work supports this preliminary analysis, but adds two further points. The most important is that there is substantial cyclical unemployment, at present. A less important one is that the impact of global inflation on inflation in individual countries has not shown any clear trend. An analysis of the US reveals the import of these changes: if the relationship between the cycle and inflation were now as it was in the 1970s, the US price level would already be falling. Fortunately, that has not been the case: otherwise, real rates of interest would now be strongly positive and balance-sheet deflation far more threatening to US stability than it has been. Encouragingly, experience during the period of economic boom, before the financial crisis, suggests the stickiness of inflation does not only work in one direction. Inflation remained in line with targets then, too. This was notably true in Spain and the UK. (See charts.) A final interesting conclusion emerges from the contrast between the performance of the US and Germany in the 1970s, which was when the Bundesbank cemented its reputation. It did not achieve this success because it never made mistakes, but because people believed it would do what was necessary to hit the target. Inflation targeting could indeed be flexible, provided it remained credible. This is important analytical work with big implications for policy. First, mistakes in estimating the degree of economic slack, which are inevitable, may not matter that much, provided people remain sure that the central banks are committed to their targets. This is one of the big benefits of a flat “Phillips curve” (the relationship between cyclical unemployment and inflation). Second, given the uncertainty about the degree of slack and the failure of inflation to respond to huge recessions, it is imperative that central banks not limit their aims to hitting their inflation targets. On the contrary, their job in a deep recession and, in some countries, alas, a worsening one, is to aim for the highest levels of activity consistent with stable inflation. Past success gives them not only the opportunity, but the obligation, to risk expansion of demand in contractionary times. Those running the European Central Bank, please note: low inflation is not enough. Third, while central banks should retain inflation targets at the core of their objectives, experience has also demonstrated that this is not enough. The idea that it is easier to clean up after a financial mess than limit a credit bubble has proved wrong. The only question is how to act. It is clearly important to build a more resilient financial system, through higher capital standards and aggressive macroprudential policies. None of this is going to be easy. A chapter in the companion Global Financial Stability Report brings out, for example, the potential drawbacks of the unconventional policies that central banks were driven to use once interest rates became close to zero. While changing inflation targets would be extremely risky, what has happened suggests that somewhat higher inflation might have been helpful. Experience certainly indicates that monetary policy is not all that effective, on its own, during a balance-sheet recession. It must be complemented by fast reconstruction of the financial system, accelerated private sector deleveraging and a willingness to employ the fiscal balance sheet to support demand, wherever feasible. Yet, for all the complacency of the pre-crisis period, it is good to know that its one clear success – that of cementing inflation expectations – has given policy makers needed policy flexibility. They must use it. 爲什麼高收入國家沒有陷入通貨緊縮的泥潭？這纔是今天的待解之謎，而不是爲什麼惡性通貨膨脹沒有出現——一些歇斯底里的人曾錯誤地預測會出現惡性通脹。奇怪的是，儘管相對於危機之前的趨勢水平，經濟產出已大幅下降，失業率也長期居高不下，通脹卻一直保持穩定。理解爲什麼會出現這種情況非常重要，因爲答案決定了能否採取正確的政策行動。幸運的是，我們有好消息。穩定的通脹似乎是對通脹目標可信度的一種嘉獎。於是政策制定者就有了採取擴張性政策的冒險空間。具有諷刺意味的是，通脹目標的成功賦予了凱恩斯主義宏觀經濟穩定政策新的活力。 國際貨幣基金組織(IMF)最新發布的《世界經濟展望》(World Economic Outlook)的一個章節就分析了這個鼓舞人心的結論，加文•戴維斯(Gavyn Davies)和保羅•克魯格曼(Paul Krugman)也都指出過這點。其出發點就是，儘管高失業率長期持續，但通脹具有粘性。因此，IMF指出，“我們找到了一條不叫的狗。” 這個現象可以從結構的角度來解釋。比如說，很多人都認爲，建築行業或者其他泡沫行業的失業工人，由於缺乏合適的技能或者身在錯誤的地方，而無法從事現在或者不遠的將來可能出現的新工作。同樣，如果放任失業率長期居高不下，最初的臨時失業則可能會轉變爲永久失業，原因是工人會失去技能和關係網，使得找工作相對較難。因此，“大衰退”(Great Recession)的持續已經使得長期失業逼近破紀錄的水平。所有這些都可能會使勞動力市場的競爭弱化。 另外一個解釋更鼓舞人心：通脹目標使人們的預期固定下來，也穩定了勞動力市場的表現。此外，這些通脹目標都接近於零。我們知道，工人們反感名義工資的降低，整個“大衰退”期間都是如此：這也是歐元區調整如此痛苦的原因之一。因此，也正是因爲這個原因，通脹將具有粘性，至少是向下的粘性。 該章節初步分析了這些可能的解釋之後，得出了三個主要結論。第一，“央行的通脹目標對預期有很強的錨定作用，而當前的通脹水平對預期沒有特別大的影響。”第二，通脹目標對通脹預期的錨定作用隨着時間的推移越來越大，而當前通脹率對通脹預期的影響逐漸減小。最後，通脹率和當前失業率之間的聯繫也相應減小。1995年之後，這種聯繫基本上已經不存在，而同時，通脹與央行通脹目標之間長期保持穩定的一致。 更爲細緻的計量經濟學研究工作支持這一初步的分析，但補充了兩點。較爲重要的一點是，當前存在明顯的週期性失業。次要的一點是，全球通脹對各國通脹的影響還沒有任何明顯的趨勢。 對美國的分析揭示了這些變化的重要性：如果現在的週期和通脹之間的關係與上世紀70年代類似，那麼美國的物價應該已經下降。幸運的是，事實並不是這樣：否則的話，實際利率就會遠高於零，資產負債表收縮對美國穩定性的威脅也會遠大於現在。令人鼓舞的是，金融危機之前的經濟繁榮期間的經驗表明，通脹的粘性不僅是朝着一個方向。那個時候通脹率與通脹目標也是一致的。這點在西班牙和英國表現尤爲明顯。（見圖表。） 最後一個有趣的結論是通過對上世紀70年代美國和德國的對比得出的，正是在那個時候德國央行(Bundesbank)確立了聲望。它不是因爲從不犯錯而獲得這種成功，而是因爲人們相信它會採取必要措施來實現目標。只要保持可信度，通脹目標就可以是靈活變動的。 這是重要的分析工作，對政策有着重要意義。 首先，評估經濟放緩程度時即使犯錯（這是不可避免的），可能也沒那麼要緊，只要人們依然確信央行致力於實現制定的目標。這是平坦的菲利普斯曲線（Phillips curve，描述週期性失業和通脹之間的關係）的較大優勢之一。 第二，鑑於經濟放緩程度的不確定性和通脹應對嚴重衰退的失敗，央行必須不將目標侷限於實現通脹目標。與此相反，當經濟深陷衰退時，或者在某些國家，當經濟衰退加劇時，它們有責任以實現與穩定的通脹水平相一致的最高經濟活動水平爲目標。過去的成功不僅賦予了它們這種機會，也賦予了它們一種職責，在收縮時期試着擴大需求。歐洲央行(ECB)的管理者們請注意：低通脹是不夠的。 第三，儘管央行需要將維持通脹目標作爲核心目標之一，經驗也表明這是不夠的。在金融動盪之後“收拾攤子”比抑制信貸泡沫要容易的觀點，已被證明是錯誤的。唯一的問題在於如何行動。通過更高的資本標準和進取性的宏觀審慎政策，建立一個更強韌的金融體系，顯然非常重要。 所有這些都不會很容易。比如，IMF同時發佈的《全球金融穩定報告》(Global Financial Stability Report)中的一章，就指出了在利率接近於零的時候，央行傾向於使用的非傳統政策的潛在缺陷。改變通脹目標確實非常危險，但事實表明較高的通脹或許是有益的。經驗證明，在資產負債表衰退期間，單單貨幣政策並不會產生多大效果，必須得到如下方面的補充：金融體系快速重組，私營領域加速去槓桿化，政府有意願在任何可行的領域通過動用財政資產負債表手段來支持需求。 另外，儘管危機前的繁榮導致了人們的自滿，它卻有一個明顯的成功之處是我們需要知道的——它強化了人們的通脹預期，這給政策制定者提供了必要的政策靈活性。他們必須用好這種靈活性。
