[2008.09.13] 经济聚焦：重新定义经济衰退

Economics focus
经济聚焦

Redefining recession
重新定义经济衰退

Sep 11th 2008
From The Economist print edition

A new yardstick for measuring slumps is long overdue
衡量经济衰退的新标准迟到了。

THERE has been a nasty outbreak of R-worditis. Newspapersare full of stories about which of the big economies will be first to dip intorecession as a result of the credit crunch. The answer depends largely on whatyou mean by “recession”. Most economists assume that it implies a fall in realGDP. But this has created a lot of confusion: the standard definition ofrecession needs rethinking.
那些令人讨厌的老话题又开始了。报纸上充斥着很多这样的故事：谁将成为受信贷危机影响而第一个进入衰退的主要经济体。答案很大程度上取决于对”经济衰退”的定义。大部分经济学家认为衰退意味着实际GDP的下降。但是这又产生了很多混乱：经济衰退的标准需要重新思考一下了。

In the second quarter of this year, America’s GDP rose at a surprisingly robustannualised rate of 3.3%, while output in the euro area and Japan fell, and Britain’s was flat. Many economistsreckon that both Japanand the euro area could see a second quarter of decline in the three months toSeptember. This, according to a widely used rule of thumb, would put them inrecession, a fate which Americahas so far avoided. But on measures other than GDP, America has been the economiclaggard over the past year.
今年二季度，美国GDP按年率计算惊人地上涨了3.3%，而同期欧元区和日本则出现了下降，英国则与一季度持平。很多经济学家预计日本和欧元区在三季度将会出现下降。根据历史经验，这意味着日本和欧元区经济进入了衰退，而美国迄今为止避免了这种厄运。但是考察GDP以外的指标发现，在过去的几年中，美国经济则要落后于欧元区和日本。

The chart looks at several different ways to judge theseverity of the economic slowdown since the start of the credit crunch inAugust 2007. On GDP growth, Americahas outperformed Europe and Japan.Unemployment, however, tells a very different tale. America’s jobless rate hit 6.1% inAugust, up from 4.7% a year earlier, and within spitting distance of its peakof 6.3% during the previous recession after the dotcom bust. Other countrieshave so far published figures only for July, but their jobless rates havebarely moved over the past year: Japan’shas risen by only 0.2%, the euro area’s has fallen slightly (though in absoluteterms it is still a bit higher than America’s). Another yardstick, GDPper head, takes account of the fact that America’spopulation is rising rapidly, whereas Japan’s has started to shrink.Since the third quarter of 2007 America’saverage income per person has barely increased; Japan’s has enjoyed the biggestgain.
下图以几种不同的形式显示并评判了自2007年8月信贷紧缩以来经济减速问题的严重性。在GDP增长方面，美国表现要好于欧元区和日本。而失业率方面则是另一番景象。8月美国的失业率从年初的4.7%上涨到了6.1%，这距离网络泡沫破灭后经济衰退时的最高值6.3%只差很小一段。其它一些国家到现在只公布了到七月份的数据，但是他们的失业率在去年几乎没有变动：日本仅仅上涨了0.2%，而欧元区是出现轻微的下跌（尽管就绝对数额来说他仍比美国要高很多）。另一个尺度–人均GDP则考虑到了美国人口数量迅速增长，而日本出现萎缩的事实。自2007年三季度以来美国的人均收入几乎没有增长；日本则是享有了最大的增幅。

To the average person, a large rise in unemployment meansa recession. By contrast, the economists’ rule that a recession is defined bytwo consecutive quarters of falling GDP is silly. If an economy grows by 2% inone quarter and then contracts by 0.5% in each of the next two quarters, it isdeemed to be in recession. But if GDP contracts by 2% in one quarter, rises by0.5% in the next, then falls by 2% in the third, it escapes, even though theeconomy is obviously weaker. In fact, America’s GDP did not decline fortwo consecutive quarters during the 2001 recession.
对普通人来说，失业率的大幅上升就意味着经济衰退。相比之下，经济学家关于衰退的标准是可笑的，他们定义GDP连续两个季度的下跌才是经济衰退。如果一个经济体在一个季度增长2%，而在接下来的而两个季度下跌0.5%，那么他应该被认为是进入衰退。但是如果GDP在一个季度下降了2%，而在下一季度增长了0.5%，接下来又下跌2%，那么他就从”经济衰退”的定义中逃脱了，尽管这个经济体明显乏力。事实上，美国的GDP在01年那次衰退中，就没有出现连续两个季度的下跌。

However, it is not just the “two-quarter” rule that isflawed; GDP figures themselves can be misleading. The first problem is thatthey are subject to large revisions. An analysis by Kevin Daly, an economist atGoldman Sachs, finds that since 1999, America’s quarterly GDP growth hason average been revised down by an annualised 0.4 percentage points between thefirst and final estimates. In contrast, figures in the euro area and Britain havebeen revised up by an average of 0.5 percentage points. Indeed, there is goodreason to believe that America’srecent growth will be revised down. An alternative measure, gross domesticincome (GDI), should, in theory, be identical to GDP. Yet real GDI has risen bya mere 0.1% since the third quarter of 2007, well below the 1% gain in GDP. Astudy by economists at the Federal Reserve found that GDI is often morereliable than GDP in spotting the start of a recession.
然而，并不只是”两个季度”法则是有缺陷的；GDP数字本身也具有误导性。第一个问题是GDP是可以被大幅修订的。高盛的一个经济学家凯文·戴利发现，自99年以来，美国从第一到第四季度的GDP增长按年率算被平均修低了0.4个百分点。相比之下，欧元区和英国的数据则被修订高了05个百分点。事实上也有足够理由相信美国最近的增长被修订低了。另一个可替代的测量标准–国内总收入（GDI）理论上是和GDP一致的。然而实际GDI自去年三季度以来上涨了仅仅0.1%，远低于GDP1%的增长。美联储一位经济学家研究表明，在测定经济进入衰退方面GDI通常要比GDP更可靠一些。

Tapping the slumpometer

These are good reasons not to place too much weight onGDP in trying to spot recessions or when comparing slowdowns across economies.The Business Cycle Dating Committee of the National Bureau of Economic Research(NBER), America’sofficial arbiter of recessions, instead makes its judgments based on monthlydata for industrial production, employment, real income, and wholesale andretail trade. It has not yet decided whether a recession has begun. But eventhe NBER’s more sophisticated approach is too simplistic in that it defines arecession as an absolute decline in economic activity. This can cause problemswhen trying to compare the depth of downturns in different cycles or acrossdifferent countries. Suppose country A has a long-term potential (trend) growthrate of 3% and country B one of only 1.5%, due to slower labour-force growth.Annual GDP growth of 2% will cause unemployment to rise in country A (making itfeel like a recession), but to fall in country B. Likewise, if fasterproductivity growth pushes up a country’s trend rate of growth, as it has inAmerica since the mid-1990s, an economic downturn is less likely to cause anabsolute drop in output.
在试图认定经济衰退或者对比各经济体经济下滑方面，我们有足够理由不必太倚重GDP。美国官方经济衰退的仲裁者–国家经济分析局经济周期测定委员会是基于工业产品、就业率、实际收入和批发零售贸易的月度数据来做出判断。他还没有确定美国是否进入经济衰退。但即使是NBER先进的算法在定义作为经济活动绝对下降的经济衰退方面也显得过于简单。在比较不同经济周期和国家间的经济低迷深度时，这种方法会产生一些问题。假定A国长期潜在经济增长率为3%，B国由于劳动力的缓慢增长，经济增长率只有1.5%。2%的GDP年增长率将会导致A国失业率的上升（这使它感觉像是进入衰退），而对B国来说则是使其失业率下降。同样的，如果生产力的快速发展推动了一国经济的增长（就像美国上个世纪90年代中期开启的经济繁荣），那么经济的低迷则不太可能导致GDP的绝对下降。

This suggests that it makes more sense to define arecession as a period when growth falls significantly below its potential rate.The IMF estimates that Americaand Britain have fastertrend growth rates than Japanor the euro area. The bottom-right chart shows that since the third quarter oflast year, growth has been below trend in all four economies, but Britain, closely followed by America, hasseen the biggest drop relative to potential.
这表明把经济衰退定义成一个时期内经济增长大幅下降并低于潜在增长率更为合理。国际货币基金组织估计美国和英国的潜在增长率要快于日本和欧元区。右下图表明自去年三季度以来，四个主要经济体的增长都低于潜在增长率，而英国，紧跟着是美国，则出现了相对于潜在增长率的最大下跌。

But even if this is a better definition of recession,potential growth rates are devilishly hard to measure and revisions to GDPstatistics are still a problem. One solution is to pay much more attention tounemployment numbers, which, though not perfect, are generally not subject torevision and are more timely. A rise in unemployment is a good signal thatgrowth has fallen below potential. Better still, it matches the definition ofrecession that ordinary people use. During the past half-century, whenever America’sunemployment rate has risen by half a percentage point or more the NBER haslater (often much later) declared it a recession. European firms are slower atshedding jobs, so unemployment may be a lagging indicator. Even so, the joblessrate has usually started to rise a few months after the start of a recession.
但是即使这是一个相对不错的经济衰退的定义，然而潜在增长率却非常难以测定，并且对GDP数据的修订也仍然是个问题。解决方法之一就是更多的关注失业人数，尽管这也不够完美，但它通常与修订无关且更加及时。失业率的上升是经济低于潜在增长率一个很好的信号。更重要的是它仍然满足普通人对经济衰退的定义。在过去的半个世纪，只要当美国的失业率上升0.5或者更多的百分点，NBER随后（经常要更久）就宣布美国经济进入衰退。欧洲公司在裁员方面比较缓慢，所以失业率作为指示器可能比较滞后。但即使是这样，失业率通常在经济进入衰退前的几个月就开始上升。

As the old joke goes: when your neighbour loses his job,it is called an economic slowdown. When you lose your job, it is a recession.But when an economist loses his job, it becomes a depression. Economists whoignore the recent rise in unemployment deserve to lose their jobs.
就像那个老笑话：当你的邻居失业了，那叫做经济低迷；当自己失业了，那就变成了经济衰退。但是当一个经济学家失业了，经济就进入萧条了。所以那些最近忽略失业率上升的经济学家们则应该下岗了。

译者：jyjnl   http://www.ecocn.org/forum/viewthread.php?tid=13967&extra=page%3D1