【英语生活】货币指标缘何“回归”

Any IoU that is accepted in payment for services rendered can be regarded as money. There is a legendary exam question about a traveller who paid for a meal on a remote island by cheque. The natives were so impressed by this strange piece of paper that they passed it from hand to hand without anyone attempting to cash it. Who then paid for the traveller's meal? (Please don't tell me.) This story illustrates the difficulty of defining, measuring and controlling the money supply; and civil wars among the monetarists on such issues have put off many people.

More practically, the money supply has been out of favour because attempts to regulate the economy via monetary targets have proved unsuccessful. Many economic technicians obviously hate money. They prefer to forecast the real economy directly from variables such as investment and trends in consumer spending. They then add something for inflation, which they try to relate to the degree of slack or overheating that exists at any one time.

The drive to put money back has clearly come from the top – for instance, from Mervyn King, governor of the Bank of England. Jean-Claude Trichet, president of the European Central Bank, has reaffirmed the role of money as a check on the forecasts of the technicians, thereby disregarding the advice of the many short-term commentators who have campaigned for the ECB to jettison the money supply, even as one of the two “pillars” in the ECB's analysis. If the welcome decline in the dollar goes much further we may also see a return of US interest in the subject.

From a long-term point of view these top central bankers are right and their critics wrong. In one of the last important articles he wrote before he died, Milton Friedman produced some dramatic graphs comparing the behaviour of broad money before and after the business cycle peaks of 1929 and 2001 in the US and in Japan in the 1990s. (A Natural Experiment in Monetary Policy, Journal of Economic Perspectives, Fall 2005).

In the US there was a dramatic fall of 30 per cent in the money stock, relative to trend, in the three years following 1929; but in a similar period following the collapse of the dotcom boom in 2001 the US money stock continued to grow “steadily and sharply”, even though it was not explicitly targeted. Japanese behaviour was less dramatic. The money stock there did not fall but slowed down to a crawl. The results were meant to bring joy to any monetarist's heart. National income (as measured by nominal gross domestic product) fell dramatically in the US after 1929. In Japan it levelled off in the stagnant 1990s. On the other hand, US GDP continued to rise after 2001 at more or less the pre-peak rate. Stock exchange movements were similar but more extreme.

Please do not throw at me the old cliché: Correlation does not imply causation. Friedman remarked in an earlier essay that such dramatic episodes were “potent in influencing public opinion”, but that to establish the key role of money involves looking at a long period of history and investigating the reasons for the changes in the money stock.

Monetary analysis has recently made a comeback because of many signs that, in their efforts to avert recession early this century, central banks permitted an excessive expansion. One of the best explanations is given by Andrew Smithers, the City of London economist, in his report World Liquidity. He notes that the ratio of US broad money to GDP is higher than at any time, with the exception of the 1930s slump and the second world war. Eurozone money supply growth is well above its “reference range” and UK annual broad money growth is at its fastest since 1990. The Organisation for Economic Co-operation and Development has just published estimates of “global liquidity” based on both money and credit measures that show it is “abundant and continuing to grow”.

There are many indications that these are not freak results. In spite of the recent correction in oil prices, other commodities are at nearly twice their 2000 level. Then there has been the announcement by Abbey, the UK bank, that it would be prepared to lend home buyers five times their gross income. Is the moral that central banks should jam down the brakes? The case against a draconian policy is that conventional price and output measures are still well under control; and there are worries about a possible recession, which could be set off for instance by the collapse of house prices in significant countries.

The main policy conclusion I
would draw is that central banks should complete as soon as possible the withdrawal of stimulus administered this century and move to a neutral interest rate policy. The monetary and related indicators also argue for the cautious option in short-term policy decisions.

Finally, central banks should aim to pull back monetary growth, but over a much longer period than the two-year horizon they have created for themselves

任何为服务支付、并被接受的借据，都可以被视作是货币。据说有一道考试题目，讲的是一位旅行者在一座偏僻小岛上，用支票来付饭钱。当地人对这张奇怪的纸片感到非常好奇，因此互相传阅，但没有人打算把它兑现。那么，谁来为这位旅行者的这顿饭埋单呢？（请别告诉我答案。）这个故事说明，对货币供应量进行定义、衡量和控制是多么地困难；而货币主义者在此类问题上的“内战”，已令许多人感到厌烦。从更为实际的角度来看，货币供应量之所以得不到经济学家的青睐，是因为通过货币目标来调控经济的尝试并不成功。许多经济技术学家明显不喜欢货币指标。他们更倾向直接通过投资和消费者支出趋势等变量，来预测实际经济的走势。他们还会加入有关通胀水平的一些因素，目的是将任何时期都存在的经济疲弱或过热的程度联系起来。

重新将货币指标纳入考虑范畴，这一举动显然源自于高层人士——例如，英国央行(Bank of England)行长金恩(Mervyn King)。欧洲央行(European Central Bank)行长让-克洛德•特里谢(Jean-Claude Trichet)已重申货币的角色——以核对经济技术学家们的预测，这种做法漠视了许多短期评论人士的建议——这些评论人士呼吁欧洲央行抛弃货币供应量这一指标，甚至不要将其作为欧洲央行政策分析的两大“支柱”之一。如果美元汇率下跌的可喜走势进一步延续，我们可能会发现，美国人也重新对这个问题产生兴趣。

从长期角度来看，这些顶级央行行长们的看法是正确的，而他们的批评者则是错误的。在米尔顿•弗里德曼(Milton Friedman)去世前撰写的最后一批重要文章中，有一篇提供了一些生动的图表，将美国1929年和2001年商业周期顶点前后的广义货币供应量变化，与日本上世纪90年代时的进行比较。[《货币政策的一个试验》(A Natural Experiment in Monetary Policy)，《经济展望期刊》(Journal of Economic Perspectives)，2005年秋季]。

在1929年之后的3年里，相对于趋势水平，美国货币存量大幅下降了30%；而在2001年互联网泡沫破灭之后的同期内，即便没有设定明确的目标，但美国的货币存量继续“稳步、大幅”增长。日本货币存量的变化没那么显著。其货币存量并未下降，但增长速度已放至缓慢。这些结果理应令货币主义者从心眼里感到高兴。1929年之后，美国的国民收入[以名义国内生产总值(GDP)衡量]急剧下降。而日本在经济陷入停滞的90年代时，其国民收入则较为平稳。另一方面，2001年之后美国GDP继续增长，速度基本保持在商业周期见顶前的水平。股市的走势与此类似，但更为极端。

请别向我抛出那句老生常谈的话：相关性并不意味着因果关系。弗里德曼曾在早些时候的一篇论文中谈道，这种戏剧性事件“会有力地影响公众观点”，但要确立货币的关键角色，需要查看很长一段时期的历史，并对货币存量变化的原因加以研究。

近年货币分析之所以重新流行，原因是许多迹象表明，本世纪初以来全球央行避免经济衰退的努力，是在允许经济过度扩张。对此，伦敦金融城经济学家安德鲁•史密瑟斯(Andrew Smithers)在其报告《全球流动性》(World Liquidity)中，提供了一个最好的解释。他指出，美国广义货币供应量占GDP比例之高，超过了以往任何时期——除上世纪30年代的经济萧条和二战以外。欧元区货币供应量的增幅超过其“参考区间”，而英国广义货币供应量的年增速则处于1990年来的最高水平。经济合作与发展组织(OECD，经合组织)刚刚发布了基于货币和信贷两种标准衡量的“全球流动性”预测，显示目前的全球流动性“非常充沛并继续上升”。

目前许多迹象表明，出现这些结果并不奇怪。尽管最近油价有所回落，但其它大宗商品的价格仍比2000年时的水平几乎高出一倍。此外，英国阿比国民银行(Abbey)已宣布，准备向购房者提供相当于他们年收入5倍的贷款。那么，各国央行是否应该有责任对经济“踩刹车”呢？央行之所以没有出台一种严格的政策，其理由在于，传统的价格和产出指标仍得到良好的控制；目前市场担心出现经济衰退——其爆发的原因可能是，一些重要国家的房价出现暴跌。

我得出的主要政策结论，是各国央行应尽快取消自2000年以来实施的经济刺激措施，转向一种中性的利率政策。货币及相关指标同时表明，央行应在短期政策方面做出谨慎的选择。

归根结底，各央行应将目标锁定在收紧货币供应量增长方面，但这应该是一个更为长期的目标，而不应仅限于这些央行给自己设定的两年期限。

译者/刘彦