Lee Li :股市最容易受到題材的影響，尤其是有心人或組織炒作不確實際、道貌岸然的題材，引發股市裏投資群眾的羊群效應與漣漪效應。今年以來，市場有心人依附於中國國家統計局公佈的中國相關經濟數據，把「中國經濟回暖」論調這塊石頭有背後動機地丟入股海裏產生漣漪效應--- 中國可以帶動全球經濟復甦，甚至可以拯救台灣經濟大衰敗的說法，進而產生羊群效應。與中國有關的概念股與基金等趁勢被炒熱，現在已經騙得全球許多人把資金往股海裡丟。
我曾在台灣的經濟部參與過工業產銷存、外銷訂單等調查、統計及分析等工作，據於理論與實務的瞭解：真實的母體數據 ≒ 樣本數據 × R，R：擴大率，所以樣本數據與R很容易被有動機的篡改，以迎合時勢需要。
具有馬克思列寧思想主義特色的中國國家統計局發布的經濟統計資料，是很容易用數理統計檢定判斷其是造假的，以下數字與案例可供檢定、判斷真假之參考：
1.中國經濟資料經調查統計到發佈所需的工時短少的不得令人懷疑：中國是人口眾多、地域廣大的經濟體，其全國性的經濟資料經調查統計到發佈的工作時間竟然比美國等主要經濟體短少很多，美國等大多以一個月為主，中國竟然只用1~2週之工作時間就完成。
2.中國經濟成長變動與用電量變動呈現矛盾相關：根據經驗法則，中國是粗放、高耗能源的經濟體，其ＧＤＰ走勢和電力生產消耗理論上應該亦步亦趨，但今年以來這兩項數據的差距，卻比過去任何時期都來得大。
3.中國經濟成長變動與政府稅收變動呈現矛盾相關：2008年整年稅收年減少10％，相較於2008年初的驟升35％，顯示經濟活動的銷售收入和生產均大幅衰落。
4.檢定中國5月份的出口數字：由於中國商品出口的主要經濟體的經濟狀況目前仍然處衰退風暴中，所以中國未來出口將持續下降的趨勢。可以推測得到，將於6月份公佈的今年的5月份出口數據將會比4月份還要低，拭目以待中國國家統計局將如何操縱此一數據。
以下分析文章是經濟學人最近一期對中國政府公佈的統計資料數據的檢定與懷疑：
The art of Chinese massage
May 21st 2009
From The Economist print edition
Is China overstating its true rate of growth?
PART of the recent optimism in world markets rests on the belief that China’s fiscal-stimulus package is boosting its economy and that GDP growth could come close to the government’s target of 8% this year. Some economists, however, suspect that the figures overstate the economy’s true growth rate and that Beijing would report 8% regardless of the truth. Is China cheating?
Economists have long doubted the credibility of Chinese data and it is widely accepted that GDP growth was overstated during the previous two downturns. In 1998-99, during the Asian financial crisis, China’s GDP grew by an average of 7.7%, according to official figures. However, using alternative measures of activity, such as energy production, air travel and imports, Thomas Rawski of the University of Pittsburgh calculated that the growth rate was at best 2%. Other economists reckon that Mr Rawski was too pessimistic. Arthur Kroeber of Dragonomics, a research firm in Beijing, estimates GDP growth was around 5% in 1998-99, for example. The top chart, plotting the official growth rate against estimates by Dragonomics, clearly suggests that some massaging of the government statistics may have gone on. The biggest adjustment seems to have been made in 1989, the year of political protests in Tiananmen Square. Officially, GDP grew by over 4%; Dragonomics reckons it actually declined by 1.5%.
China’s growth in the first quarter of this year has led some to conclude that the government is up to the same old tricks. According to official figures, GDP was 6.1% higher than a year earlier. Yet electricity production in the first quarter was 4% lower than it had been a year earlier; in comparison, production grew by 16% in the year to the first quarter of 2008. In the past, GDP and electricity output have moved broadly together, although it is not a one-to-one relationship (see bottom chart). But the gap between the two lines is now wider than it has ever been. Given that power statistics are less likely to have been tampered with than politically sensitive GDP figures, is this evidence that the latter have been fiddled?Probably not. Paul Cavey, an economist at Macquarie Securities, argues that the discrepancy is explained by the fact that energy-guzzling heavy industries, such as steel and aluminium, bore the brunt of the slowdown last year. Mr Cavey calculates that the metals industry accounted for 40% of the growth in electricity consumption in 2001-07, but only 16% of the increase in industrial production. Steel output fell by more than 10% in the year to the fourth quarter, so it is hardly surprising that energy use dropped.
Distrust of the GDP numbers has prompted Capital Economics, a research firm based in London, to create its own proxy of economic activity, which includes electricity output, domestic freight volumes, cargo traffic at ports, passenger transport and floor area under construction. It suggests that GDP growth slowed to only 4% in the year to the first quarter. However, it tracks mostly industrial activity, and thus excludes two-fifths of the economy, most notably services, which are growing faster.
Then there are government tax revenues. These have fallen by 10% over the past year, compared with a surge of 35% in early 2008, suggesting that incomes and output have tumbled. But Stephen Green, an economist at Standard Chartered, says that revenues were inflated in early 2008 by a sharp rise in taxes from the boom in land sales, which has since subsided. Another possible distortion is that local officials may be hiding tax revenue to make their finances appear worse, in order to get more money from Beijing to finance infrastructure projects.
Overall, Dragonomics’s Mr Kroeber thinks that GDP growth in the year to the first quarter of 2009 was not significantly overstated. One reason why others are more suspicious is the fact that the National Bureau of Statistics (NBS) does not publish quarterly GDP figures as developed economies do; its year-on-year changes give it more scope to smooth growth rates (for example, output probably did stall over the past two quarters). To be fair, many developing countries do this as well. One reason is that seasonal adjustment is tricky in such countries where the shift from agriculture to industry changes the pattern of seasonality over time, says Mr Kroeber.
Cutting the fudge
And for all today’s misgivings, Beijing’s growth estimates consistently proved to be too low until recently. One of the quirks of Chinese data has long been that the provinces reported higher numbers than the central government did—a phenomenon that was put down to the fact that local officials inflated growth rates in order to get promoted. Yet the NBS GDP figures have almost always been revised upwards. For example, growth in 2007 was first reported as 11.4%, but in January it was marked up to 13%.
The NBS has improved its data-gathering methods in recent years, by extending its coverage of services, for example. This month Beijing also introduced new penalties for officials who falsify statistics. But the real test is whether the government itself is prepared to publish politically embarrassing bad news. There are encouraging signs that it is becoming more open. On May 14th an essay on the NBS website by Xu Xianchun, the bureau’s deputy director, was surprisingly frank about some of the flaws in Chinese statistics. Mr Xu admitted, for example, that the retail-sales numbers include some purchases by companies and the government, which should not be counted as consumption. He estimated that consumer spending in the first quarter grew by 9%, compared with the 15% increase reported for retail sales.
Andy Rothman, an economist at CLSA, a regional broker, believes that Chinese statistics are much more trustworthy than they used to be. This is partly because there are alternative numbers to go on; CLSA, for example, produces its own purchasing-managers’ index. There are also more private-sector economists keeping tabs on China than there were a decade ago. The more eyes there are on China, and the more crucial its economic performance becomes for the rest of the world, the harder it is for officials to tamper with the speedometer.
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