作者：英国《金融时报》首席经济评论员马丁•沃尔夫(Martin Wolf) 2009-05-08

通胀目标制失败了吗？各国央行大多没有因为这场危机而受到指责。他们不应受到指责吗？

就在5年前，现任美联储(Fed)主席本•伯南克(Ben Bernanke)发表了一场关于“大缓和”(Great Moderation)的演讲。所谓“大缓和”，意指过去20年通胀和产出的波动不断减弱。在演讲中，他强调了改良货币政策的有益作用。央行官员们感到自豪。自豪之后是失落。如今，他们正疲于应对上世纪30年代以来最严重的衰退、依靠政府“维生”的银行体系以及通缩隐患。怎会变得如此糟糕？

这并非小事。近30年来，政策制定者和学界越来越确信，通过推行通胀目标制，他们找到了法定货币（fiat money，或人造货币）的“圣杯”。这是一段漫长的旅途，从19世纪的金本位开始，历经上世纪20年代的金汇兑本位制、30年代的金融混乱、50年代和60年代实行浮动汇率制的布雷顿森林体系、1971年结束美元与黄金的兑换，以及70年代和80年代的货币目标制。

曾任美联储理事的哥伦比亚大学(Columbia University)教授弗雷德里克•米什金(Frederic Mishkin)强烈支持通胀目标制，他在2007年出版的一本书中提出，通胀目标制是一种“集合了各种信息的货币政策管理策略”*。换句话说，通过变量对经济活动及通胀前景的影响，通胀目标制将一切相关变量——汇率、股价、房价和长期债券价格——纳入了考虑之中。既然我们正在承受金融体系的内爆，这种观点已不再可信。

同样不足为信的是与之相关的一种观点，认为最好是应对资产价格泡沫的后果，而不是预先刺破泡沫。这种观点也是美联储提出的。米什金教授写道：“认为政府官员（即使是央行官员）比私人市场更清楚资产价格应处于何种水平的看法极其狂妄。”如今，鉴于伴随着私人信贷大幅扩张的资产价格泡沫破灭后，金融危机造成了巨额成本，几乎没有人会在意这种狂妄。

对“大缓和”的自满，首先带来了“大调整”，接着是“大衰退”。私人部门对风险盲目自大，政策制定者何尝不是！

那么，货币政策扮演着什么角色？对央行的相关批评可分为三种：

首先，曾在布什政府任职的斯坦福大学(Stanford University)教授约翰•泰勒(John Taylor)认为，美联储在本世纪最初几年实行过低利率是迷失了方向，忽视了以他的名字命名的“泰勒规则”（此规则将利率与通胀和产出挂钩）**，从而导致了房市繁荣和随后的毁灭性崩溃。

泰勒还有一种观点。他指出，美联储将利率降得过低，也造成了其他央行将利率置于过低水平，从而在世界大部分地区引发了泡沫。回想起来，比如，英国央行(BoE)的自主性其实远逊于多数人的想像：英国与美国的息差越大，流入英国的“热钱”就越多。这导致信贷发放标准降低，于是出现了信贷泡沫。

其次，许多批评家认为，鉴于资产价格暴跌会造成巨大破坏，央行应将目标瞄准资产价格。伦敦Smithers & Co的安德鲁•史密瑟斯(Andrew Smithers)在最近的一份报告（《通胀：既非不可避免也并非有益》(Inflation: Neither Inevitable Nor Helpful)，2009年4月30日）中指出：“由于放任资产泡沫生成，央行已丧失了对本国经济的控制，致使通胀和通缩风险都有所加剧。”
因此，当名义资产价格和相关信贷供应与名义收入和商品及服务价格不匹配时，就可能发生以下两种情况中的一种：资产价格暴跌，这可能造成大量破产事件、经济萧条和通缩；或者商品及服务价格被推高到与资产价格相应的高水平，这种情况下将出现通胀。在短期内，央行还会被迫采取货币效应不可预料的非常规货币政策。

最后，具有“奥地利”传统的经济学家认为，央行的过失在于设定的利率低于“自然利率”。弗里德里希•哈耶克(Friedrich Hayek)指出，上世纪20年代就出现过这种情况。其结果是资源错配，并导致问题信贷爆炸性增长。之后，在经济低迷中，资产负债表通缩将会出现，随着价格下跌和收入萎缩而严重恶化——美国经济学家欧文•费雪(Irving Fisher)在1933年出版的《大萧条的债务-通缩理论》(Debt-Deflation Theory of Great Depressions)中就阐述了这种观点。

不管人们赞同哪种批评观点，回想起来，货币政策过于宽松似乎都是显而易见的。结果，我们如今面临两个挑战：收拾残局和构思一种新的货币政策方法。

关于前者，我们有三种选择：清算、通胀或增长。清算政策将造成大规模的破产，导致大量现有信贷崩溃。这是一种疯狂的选择。蓄意的通胀政策将重新唤醒通胀预期，不可避免地引发新一轮衰退——只为了重建货币稳定。因此，我们只剩下了增长的选择。至关重要的是维持需求，恢复增长，同时避免引发新一轮信贷泡沫。这会很难。所以我们首先就不能陷入泥潭。

关于后者，短期内的选择肯定是“通胀目标制加”。“减项”可能是美联储的“风险管理”方式。事实证明，美联储此种方式会对负面经济冲击做出过强的非对称性反应。“加项”可能是：每当资产价格快速上涨和达到异常高位时，就应“逆风而行”，同时，对具有系统重要性的金融机构的资本要求采取反周期的“宏观审慎”策略。

对货币政策来说，这场突如其来的危机无疑是场灾难。我们多数人（包括我）都以为，我们终于找到了圣杯。现在我们知道，它只是一个幻觉。这或许是法定货币的最后机会。如果不能使它比以前更好地发挥作用，谁知道我们的后辈可能做出什么决定？或许，在绝望之中，他们甚至会拥抱我仍视之为荒谬的黄金。

* Monetary Policy Strategy（麻省理工大学(MIT)，2007年）

** Getting Off Track（胡佛学院(Hoover Institution)，2009年）

WHY CENTRAL BANK POLICIES MUST ALSO BE PUT IN QUESTION

By Martin Wolf 2009-05-08

Did inflation targeting fail? Central banks have mostly escaped blame for the crisis. Do they deserve to do so?

Just over five years ago, Ben Bernanke, now chairman of the Federal Reserve, gave a speech on the “Great Moderation” – the declining volatility of inflation and output over the previous two decades. In this he emphasised the beneficial role of improved monetary policy. Central bankers felt proud of themselves. Pride went before a fall. Today, they are struggling with the deepest recession since the 1930s, a banking system on government life-support and the danger of deflation. How can it have gone so wrong?

This is no small matter. Over almost three decades, policymakers and academics became ever more confident that they had found, in inflation targeting, the holy grail of fiat (or man-made) money. It had been a long journey from the gold standard of the 19th century, via the restored gold-exchange standard of the 1920s, the monetary chaos of the 1930s, the Bretton Woods system of adjustable exchange rates of the 1950s and 1960s, the termination of dollar convertibility into gold in 1971, and the monetary targeting of the 1970s and 1980s.

Frederic Mishkin of Columbia University, a former governor of the Federal Reserve and strong proponent of inflation targeting, argued, in a book published in 2007, that inflation targeting is an “information-inclusive strategy for the conduct of monetary policy”.* In other words, inflation targeting allows for all relevant variables – exchange rates, stock prices, housing prices and long-term bond prices – via their impact on activity and prospective inflation. Now that we are living with the implosion of the financial system, this view is no longer plausible.

No less discredited is the related view, also advanced by the Fed, that it is better to deal with the aftermath of asset price bubbles than prick them in advance. Prof Mishkin wrote that “it is highly presumptuous to think that government officials, even if they are central bankers, know better than private markets what the asset prices should be”. Today, few would mind such presumption, given the costs of the financial crises that follow asset price bubbles accompanied by big expansions in private credit.

Complacency about the Great Moderation led first to a Great Unravelling and then a Great Recession. The private sector was complacent about risk. But so, too, were policymakers.

What role then did monetary policy play? I can identify three related critiques of the central banks.

First, John Taylor of Stanford University, a former official in the Bush administration, argues that the Fed lost its way by keeping interest rates too low in the early 2000s and so ignoring his eponymous Taylor rule, which relates interest rates to inflation and output.** This caused the housing boom and the subsequent destructive bust (see charts).

Prof Taylor has an additional point: by lowering rates too far, the Fed, he argues, also caused the rates offered by other central banks to be too low, thereby generating bubbles across a large part of the world. In retrospect, for example, the autonomy of the Bank of England was much smaller than most imagined: the wider the interest rate gap vis-a-vis the US, the more “hot money” flowed in. This induced a lowering of standards for granting credit and so a credit bubble.

Second, a number of critics argue that central banks ought to target asset prices because of the huge damage subsequent collapses cause. As Andrew Smithers of London-based Smithers & Co notes in a recent report (Inflation: Neither Inevitable Nor Helpful, 30 April 2009), “by allowing asset bubbles, central banks have lost control of their economies, so that the risks of both inflation and deflation have increased”.

Thus, when nominal asset prices and associated credit stocks go out of line with nominal income and prices of goods and services, one of two things is likely to happen: asset prices collapse, which threatens mass bankruptcy, depression and deflation; or prices of goods and services are pushed up to the level consistent with high asset prices, in which case there is inflation. In the short term, central banks also find themselves driven towards unconventional monetary policies that have unpredictable monetary effects (see chart).

Finally, economists in the “Austrian” tradition argue that the mistake was to set interest rates below the “natural rate”. This, argued Friedrich Hayek, also happened in the 1920s. The result is misallocation of resources. It also generates explosive growth of unsound credit. Then, in the downturn – as the American economist, Irving Fisher, argued in his Debt-Deflation Theory of Great Depressions, published in 1933 – balance-sheet deflation will set in, greatly aggravated by falling prices and shrinking incomes.

Whichever critique one accepts, it seems clear, in retrospect, that monetary policy was too loose. As a result, we now face two challenges: clearing up the mess and designing a new approach to monetary policy.

On the former, we have three alternatives: liquidation; inflation; or growth. A policy of liquidation would proceed via mass bankruptcy and the collapse of a large part of the existing credit. That is an insane choice. A deliberate policy of inflation would re-awaken inflationary expectations and lead, inevitably, to another recession, in order to re-establish monetary stability. This leaves us only with growth. It is essential to sustain demand and return to growth without stoking up another credit bubble. This is going to be hard. That is why we should not have fallen into the quagmire in the first place.

On the latter, the choice, in the short term, is certainly going to be “inflation targeting plus”. “Out” is likely to be the “risk management” approach of the Fed, which turned out to give an unduly asymmetric response to negative economic shocks. “In” is likely to be “leaning against the wind” whenever asset prices rise rapidly and to exceptionally high levels, along with a counter-cyclical “macro-prudential” approach to capital requirements in systemically significant financial institutions.

This unforeseen crisis is surely a disaster for monetary policy. Most of us – I was one – thought we had at last found the holy grail. Now we know it was a mirage. This may be the last chance for fiat money. If it is not made to work better than it has done, who knows what our children might decide? Perhaps, in despair, they will even embrace what I still consider to be the absurdity of gold.

* Monetary Policy Strategy (Massachusetts Institute of Technology, 2007); ** Getting Off Track (Hoover Institution, 2009).