主题：【原创】经济学读书心得 -- 科大胡不归

One reason to be suspicious of GDP figures is that China is always one of the first countries to report them, usually only two weeks after the end of each quarter. Most developed economies take between four and six weeks to produce them.

For instance, the figures first published for 2004 showed that the sum of the provincial GDPs was 19% bigger than the reported national figure. Lo and behold, in 2005, after a national economic census picked up more services, the NBS revised its GDP up by 17%; it also lifted the annual growth rate over the previous decade.

But just as local officials have an incentive to inflate numbers, so Beijing has had reason recently to understate them: it wants to slow the red-hot economy.

For instance, despite severe snow storms and weaker net exports, first-quarter GDP growth slowed by less than expected and by much less than did industrial production. The government may well have made the figures look stronger to avoid criticism of its tighter credit policy.

The closely watched figures for fixed-asset investment are among the least reliable. They include purchases of land, which only reflect changes in ownership, not an increase in capacity or value added.

In contrast, consumer spending is almost certainly much higher and growing faster than official figures suggest. Retail sales are often used as a proxy for private consumption, but they exclude services, the fastest-growing slice of households' budgets.

Data for 36 cities collected by the National Development and Reform Commission show that inflation for medical care and education has been running at 5-10% since 2001, well above the 1-2% reported in the CPI.

The prize for the dodgiest figures goes to the labour market. The quarterly urban unemployment rate is meaningless because it excludes workers laid off by state-owned firms as well as large numbers of migrant workers, who normally live in urban areas but are not registered. Wage figures are also lousy. There has recently been much concern about the faster pace of increase in average urban earnings. But this series does not cover private firms, which are where most jobs have been created in recent years.

Now that China is such an engine of global growth, it urgently needs to improve its economic data. Only a madman would drive a juggernaut at full speed with a faulty speedometer, a cracked rear-view mirror and a misty windscreen.