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2008=1929? 浩劫归来?(推荐)  

2009-03-25 11:28:08|  分类: 默认分类 |  标签: |举报 |字号 订阅

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中文博主按:这是我的美女同事译的。我对她很佩服,这么长的文章!她对理论的把握,无懈可击!我只对一开始的部分,作了一点文字的工作。光荣归于我的美女同事!

2008 = 1929?

Ithas become fashionable lately to see parallels between the currentfinancial turmoil and what happened during the Great Depression. See,for example, Paul Krugman's latest column.
最近,将目前的金融动荡跟大萧条所发生的一切相提并论,变得流行起来。看看Paul Krugman最新的专栏吧。

Letme remind everyone of one important difference: Deflation was a largepart of the story of the 1930s, and that does not seem like asignificant risk today. Here is a relevant passage from my favorite intermediate macro textbook (sorry, I cannot post the referenced figure):
我想提醒大家,一个重要的差异:通货紧缩是1930年代故事里的主角之一,而如今它好像算不得一个严重的风险。下面这一段,来自我喜欢的中级宏观教科书(不好意思,我不能把相关的图贴上来):


The Money Hypothesis Again: The Effects of Falling Prices
又见货币假设:价格下降的影响

From1929 to 1933 the price level fell 25 percent. Many economists blamethis deflation for the severity of the Great Depression. They arguethat the deflation may have turned what in 1931 was a typical economicdownturn into an unprecedented period of high unemployment anddepressed income. If correct, this argument gives new life to the moneyhypothesis. Bause the falling money supply was, plausibly,responsible for the falling price level, it could have been responsiblefor the severity of the Depression. To evaluate this argument, we mustdiscuss how changes in the price level affect income in the IS?LM model.
从1929到1933年,价格水平下降了25%。许多经济学家说,这样的通货紧缩,才使得大萧条如此的惨烈。他们认为,正是由于通缩,使得1931年陷入了史无前例的失业高企和收入低迷,本来它仅仅是个一般的经济衰退而已。如果这个观点正确的话,这种说法就使得货币假设重获新生。因为,理论上说来,货币供给的下降,导致了价格水平的下降,因而也就导致了大萧条的惨烈。要想知道这个说法的价值所在,我们就必须在IS-LM模型中,来讨论价格变化对收入的影响。


The Stabilizing Effects of Deflation
通缩会促进经济稳定

Inthe IS?LM model we have developed so far, falling prices raise income.For any given supply of money M, a lower price level implies higherreal money balances M/P. An increase in real money balances causes anexpansionary shift in the LM curve, which leads to higher income.
在目前的IS-LM模型中,价格的下降将提高收入。对任一给定的货币供应量M,更低的价格水平意味着更高的真实货币余额M/P。真实货币余额的增加将导致LM曲线扩张性的外移,因此导致了更高的收入。

Anotherchannel through which falling prices expand income is called the Pigoueffect. Arthur Pigou, a prominent classical economist in the 1930s,pointed out that real money balances are part of households' wealth. Asprices fall and real money balances rise, consumers should feelwealthier and spend more. This increase in consumer spending shouldcause an expansionary shift in the IS curve, also leading to higherincome.
价格下降导致收入提高的另外一个途径是庇古效应(Pigou effect)。Arthur Pigou是1930年代一位著名的古典经济学家。他指出,真实的货币余额是家庭财富的一部分。价格下降,真实的货币余额将上升,消费者会感觉更富有,因而花得更多。消费的增加将导致IS曲线扩张性的外移,同样也导致了更高的收入。

These two reasons led some economists in the 1930s tobelieve that falling prices would help stabilize the economy. That is,they thought that a decline in the price level would automatically pushthe economy back toward full employment. Yet other economists were lessconfident in the economy's ability to correct itself. They pointed toother effects of falling prices, to which we now turn.
就是这两个理由,使得1930年代的一些经济学家相信,价格的下降有助于稳定经济。也就是说,他们认为,价格水平的下降将自动将经济推向完全就业。然而,其他的经济学家对于经济的自我纠正能力并不是很有信心。他们指出了价格下降的其他影响,我们下面就来谈谈。


The Destabilizing Effects of Deflation
通缩会破坏经济稳定

Economistshave proposed two theories to explain how falling prices could depressincome rather than raise it. The first, called the debt?deflationtheory, describes the effects of unexpected falls in the price level.The second explains the effects of expected deflation.
经济学家提出两个理论来解释,低价格是如何降低收入(而不是提高收入)的。第一个,叫债务-通缩理论(debt-deflation theory),说的是价格水平的非预期下降造成的影响;第二个理论解释了预期的通缩带来的影响。

Thedebt?deflation theory begins with an observation from Chapter 4:unanticipated changes in the price level redistribute wealth betweendebtors and creditors. If a debtor owes a creditor $1,000, then thereal amount of this debt is $1,000/P, where P is the price level. Afall in the price level raises the real amount of this debt??the amountof purchasing power the debtor must repay the creditor. Therefore, anunexpected deflation enriches creditors and impoverishes debtors.
债务-通缩理论开始于第4章的一个论断:预期外的价格水平变化,导致了财富在借贷双方的重新分配。如果一个借款人欠贷款人$1000,那么真实的债务水平就是$1000/P,P就是价格水平。价格水平的下降提高了真实债务――即借款人应该偿还贷款人的购买力。因此,未预期的通缩将富了贷款人,穷了借款人。

Thedebt?deflation theory then posits that this redistribution of wealthaffects spending on goods and services. In response to theredistribution from debtors to creditors, debtors spend less andcreditors spend more. If these two groups have equal spendingpropensities, there is no aggregate impact. But it seems reasonable toassume that debtors have higher propensities to spend thancreditors??perhaps that is why the debtors are in debt in the firstplace. In this case, debtors reduce their spending by more thancreditors raise theirs. The net effect is a reduction in spending, acontractionary shift in the IS curve, and lower national income.
债务-通缩理论随即断定,这样的“财富再分配效应”,会影响商品与服务的支出。财富从借款人转移到贷款人,使得借款人花得更少,贷款人花得更多。如果这两群人具有相同的消费倾向,总体来看就没影响了。但是,有理由假设借款人具有更高的消费倾向――也许这就是为什么借款人负债的首要原因。这样,借款人减少的花费要超过贷款人增加的花费。净效用就是支出的减少,IS将向相反的方向变动,从而导致更低的国民收入。

Tounderstand how expected changes in prices can affect income, we need toadd a new variable to the IS?LM model. Our discussion of the model sofar has not distinguished between the nominal and real interest rates.Yet we know from previous chapters that investment depends on the realinterest rate and that money demand depends on the nominal interestrate. If i is the nominal interest rate and πe is expected inflation,then the ex ante real interest rate is i - πe. We can now write theIS?LM model as
 要理解预期到的价格变化对收入的影响,需要在IS-LM模型上加入一个新变量。迄今为止,我们讨论的模型没有区分名义利率和实际利率。设i是名义利率,πe是预期的通胀率,那么实际利率就是:i – πe。IS-LM可以写成:

IS: Y = C(Y - T) + I(i - πe) + G
LM: M/P = L(i, Y)

Expected inflation enters as a variable in the IS curve. Thus, changes in expected inflation shift the IS curve.
预期通胀,作为变量,进入了IS方程。这样,预期通胀的变化将导致IS曲线移动。

Let'suse this extended IS?LM model to examine how changes in expectedinflation influence the level of income. We begin by assuming thateveryone expects the price level to remain the same. In this case,there is no expected inflation (πe = 0), and these two equationsproduce the familiar IS?LM model. Figure 11-8 depicts this initialsituation with the LM curve and the IS curve labeled IS1. Theintersection of these two curves determines the nominal and realinterest rates, which for now are the same.
让我们使用这个“扩展了的IS-LM模型”,来分析预期的通胀变化如何影响收入水平。假设每个人都料到价格水平保持不变,这样就不存在预期到的通胀(πe = 0),两个等式就是我们熟悉的IS-LM模型。图11-8描绘了LM曲线和IS曲线的初始状态,IS曲线标记为IS1。两条曲线的交点决定了名义利率与实质利率。目前它们是一样的。

Now suppose thateveryone suddenly expects that the price level will fall in the future,so that πe becomes negative. The real interest rate is now higher atany given nominal interest rate. This increase in the real interestrate depresses planned investment spending, shifting the IS curve fromIS1 to IS2. (The vertical distance of the downward shift exactly equalsthe expected deflation.) Thus, an expected deflation leads to areduction in national income from Y1 to Y2. The nominal interest ratefalls from i1 to i2, while the real interest rate rises from r1 to r2.
现在,假设每个人都突然预料到价格水平要下降,这样πe为负。实际利率比名义利率更高。实际利率的增加压制了“计划的投资支出”,将IS曲线从IS1移到IS2。(下移的垂直距离正好等于期望的通缩水平。)因而,预期的通缩导致国民收入从Y1减少到Y2,名义利率从i1下降到i2,同时实际利率从r1增加到r2。

Hereis the story behind this figure. When firms come to expect deflation,they become reluctant to borrow to buy investment goods because theybelieve they will have to repay these loans later in more valuabledollars. The fall in investment depresses planned expenditure, which inturn depresses income. The fall in income reduces the demand for money,and this reduces the nominal interest rate that equilibrates the moneymarket. The nominal interest rate falls by less than the expecteddeflation, so the real interest rate rises.
这个图形后面藏着这样的故事。企业预期到通缩(注:感谢网友“卫平布劳格”的指正)的时候,他们就不愿意借钱购买投资品,因为他们相信日后偿还的时候要使用值钱得多的美元。投资的下降压制了计划的支出,并进而降低了收入。收入的降低减少了货币需求,这又会降低名义利率以使货币市场保持均衡。名义利率下降的幅度没有预期通缩的幅度大,因而实际利率上升。

Note that there is acommon thread in these two stories of destabilizing deflation. In both,falling prices depress national income by causing a contractionaryshift in the IS curve. Because a deflation of the size observed from1929 to 1933 is unlikely except in the presence of a major contractionin the money supply, these two explanations give some of theresponsibility for the Depression??especially its severity??to the Fed.In other words, if falling prices are destabilizing, then a contractionin the money supply can lead to a fall in income, even without adecrease in real money balances or a rise in nominal interest rates.
注意这两个“非稳理论”之间有个共同的思路。价格的下降通过推动IS曲线相反的移动,从而减少了国民收入。由于从1929到1933观察到的通缩如此可怕,不可能排除货币供应的严重紧缩,因而这两个解释指出了美联储在萧条问题――特别是其严重程度――上应该承担的部分责任。换句话说,如果价格下降会破坏稳定,货币供应的紧缩就会导致收入的减少,甚至不需要真实货币余额的下降或者名义利率的上升。


Could the Depression Happen Again?
大萧条还会再次发生吗?

Economistsstudy the Depression both because of its intrinsic interest as a majoreconomic event and to provide guidance to policymakers so that it willnot happen again. To state with confidence whether this event couldrecur, we would need to know why it happened. Because there is not yetagreement on the causes of the Great Depression, it is impossible torule out with certainty another depression of this magnitude.
经济学家研究萧条,既是对这个经济事件本身抱有兴趣,也是想给政策制定者支支招,免得重蹈覆辙。想要满怀信心地判断这种事还会不会再次发生,我们还需要知道它为什么会发生。对于大萧条发生的原因意见不一,我们就没法确切无疑地排除,可能再来一次大规模的萧条。


Yetmost economists believe that the mistakes that led to the GreatDepression are unlikely to be repeated. The Fed seems unlikely to allowthe money supply to fall by one-fourth. Many economists believe thatthe deflation of the early 1930s was responsible for the depth andlength of the Depression. And it seems likely that such a prolongeddeflation was possible only in the presence of a falling money supply.
然而,大部分经济学家都相信,导致大萧条的错误不会重演。美联储似乎不会让货币供应量下降1/4。许多经济学家相信,正是1930年代早期的通缩,才使得大萧条如此深重、如此长久。而且,好像只有在货币供应下降的情况下,通货紧缩才会拖得这么久。

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