So the big story of the day is that China has overtaken Japan, moving up to become the world's second biggest economy.
Please forgive me if I manage to contain my excitement. You see, the media stories about China's economy leap-frogging Japan's are based on the latest quarterly figures for gross domestic product. And GDP figures are slippery things at the best of times.
Sure, according to numbers released yesterday, Japanese growth all but stalled over the three months to the end of June. As a result, Japan's GDP - its total output of goods and services - for the quarter came to 119 trillion yen (HK$10.72 trillion). At the average exchange rate for the quarter, that equals 8.8 trillion yuan, which is clearly lower than China's economic output of 9.1 trillion yuan (HK$10.39 trillion) over the same three-month period.
Hooray! China has surpassed Japan at last.
Except that the story is hardly big news. A quick look back at the past data shows that this is not the first time China's quarterly output has overtaken Japan's. According to the raw numbers, China's GDP also topped Japan's in the fourth quarter of last year (see the first chart below). Then in the first quarter of this year, China's output slipped back, and Japan regained its second place.
The trouble is that raw quarterly GDP numbers are a terribly unreliable indicator of relative economic development. For one thing, they are massively distorted by seasonal variations. In China, for example, the lunar new year holiday drags down first quarter data, while quirks in the local business environment tend to exaggerate output in the last three months of the year. As a result, the raw numbers frequently show fourth quarter GDP exceeding first quarter output by 50 per cent or more.
And for another thing, the latest quarterly numbers are little more than rough preliminary estimates. Although China's number-crunchers have traditionally avoided admissions of fallibility, rarely making revisions to their initial announcements, Japan's statisticians have no such hang-ups. Their revisions are frequent and often large, so that final GDP numbers often bear little resemblance to the preliminary figures announced six weeks after the end of each quarter.