The International Monetary Fund will mark down this year's anticipated growth by half a percentage point because of a change in the way national economies are measured.

Earlier this week, the World Bank, the IMF's sister institution, recalculated the way it computes economic-growth statistics based on a far more thorough analysis of prices in 146 nations. By revising so-called purchasing power parity statistics, the bank sought a better way to compare wealth and poverty among nations. The stats take into account the different cost of goods and services in different countries -- for instance, a haircut costs a lot less in Beijing than Boston.

The recalculations are the beginning of what is likely to be a makeover of the official portrait of the global economy. IMF rules require it to use World Bank purchasing-power statistics. As a result, Simon Johnson, the IMF's chief economist, said the IMF's October forecast that the world economy would grow 5.2% now translates into growth of 4.7% -- even though no individual country's economy has grown more slowly.

The final number likely will be lower still to reflect subprime-mortgage turmoil and the global credit crunch. The IMF will release its next formal forecast of global growth at the end of next month.

Mr. Johnson says the basic trends in global economic growth remain true despite the statistical change. China continues to be the single biggest driver of global growth, accounting for 27% of the growth this year. India's contribution is about 9%.

But the statistics temper somewhat the view of the economic power of big emerging economies, he said. 'China has been driving a lot of people's interpretation of how well the world economy is doing,' he said. 'We just haven't been doing as well as we thought.'

Based on the new statistics, the World Bank earlier this week said China's and India's economies were smaller than previously estimated, and their share of the world economic might diminished. Under the old purchasing power parity statistics, China accounted for 14.8% of global economic output and India 6.3%. Under the new figures, China's share for 2005 was reduced to 9.7% and India's to 4.3%. The U.S. share, meanwhile, jumped to 22.5% from 20.8%, suggesting a bigger gap than previously estimated between the world's economic powers and emerging economies.

The statistical changes will have real-life consequences. The IMF now is recalculating the voting shares of its members with an eye to awarding big developing nations a larger share. The outcome of that effort is more in doubt if some big developing nations have smaller economies than previously estimated.

IMF and World Bank loan programs also depend on accurate national counts of poverty to see how best to construct projects. The new statistics will scramble poverty counts. A World Bank spokesman said new poverty numbers will be released in a few months.
因对各国经济产出的计算方法发生调整，国际货币基金组织(IMF)对今年的全球增长预期将下调0.5个百分点。

本周早些时候，IMF的姊妹机构世界银行(World Bank)在对146个国家的物价进行了更透彻的分析之后决定，调整其对各国经济增长幅度的计算方式。该行修订了所谓的购买力平价统计方法，以求更合理地比较各国间的贫富程度。新的统计方法考虑到了不同国家各类商品和服务的不同价格，比如，在北京理发的价格就比在波士顿便宜很多。

这次重新计算之后，对全球经济的官方描述将有可能因此发生改变。该组织首席经济学家西蒙•约翰逊(Simon Johnson)表示，IMF的章程规定其要采用世行的购买力数据，因此，IMF十月份对全球经济增长作出的5.2%的预测值将调整为4.7%，虽然其中各个国家的增长率均未作向下调整。考虑到次贷风波及全球信贷危机的影响，最终数据可能会更低。新的正式预测数据将在下个月末公布。

约翰逊说，虽然预测统计数字有所调整，但全球经济增长的基本趋势并未改变。中国仍将是推动全球增长的最大的单一经济体，对今年全球增长的贡献率是27%，印度的贡献率在9%左右。

不过他说，从统计得到的部分新兴经济大国的经济实力状况将有所削弱。受中国高速发展的鼓舞，人们以为全球经济也同样一片大好。但实际情况并非如此。

根据新的统计数字，世界银行本周早些时候说，中国和印度的经济规模没有以前估计的那么大，它们在全球经济产出中所占的比例可能也要相应下调。根据以前的购买力平价统计数字，中国和印度的比例分别是14.8%和6.3%，而根据对2005年产出数据的最新统计结果，这组数字分别是9.7%和4.3%。美国所占的份额则从原来的20.8%上升到22.5%，显示世界经济强国与新兴经济体的差距比人们以前认为的要大。

统计数字的改变将对现实世界产生一定的影响。IMF原本正在重新计算成员国的投票权，以给予发展中国家更大的发言权，但如果新兴经济大国的经济规模并不像人们原来以为的那么大，则这一努力的意义将要打个问号。

IMF和世界银行的贷款项目也将取决于对一个国家贫困情况的精确计算，以确定如何制定最佳项目计划。新的统计数字将使贫困统计变得复杂化。世行一位发言人表示，新的贫困数字要到几个月后才能发布。