Next Friday China will publish economic growth data for the second quarter of the year.
The key number is likely to show that gross domestic product was up by around 7.5 per cent from the same period in 2011. Compared with a figure of 8.1 per cent in the first quarter, the number will indicate a significant, although gentle, slowing in China's rate of economic growth.
But lots of people will question the figure's accuracy, especially following a New York Times story last month alleging that 'local and provincial officials are falsifying economic statistics' to disguise the true depth of China's slowdown.
Doubts about China's economic data are nothing new, of course. One good reason for questioning their accuracy is the sheer speed with which they are published. In an economy as large and diverse as China, the National Bureau of Statistics manages to collect, collate and release GDP data within two weeks of the end of the quarter.
In Hong Kong, where the economy is smaller and data collection easier, it takes a full six weeks.
What's more, local officials in China have powerful political incentives to exaggerate the output figures for their districts. This produces big distortions. In 2009, for example, all but one of China's 31 provinces announced a growth rate higher than the national average. In 2010, China's GDP was 40 trillion yuan (HK$49.1 trillion). But if you add up the numbers declared by each province, you get a total of 44 trillion; a discrepancy of 10 per cent.
As a result, investors have long looked to hard, real world indicators like electricity production as a more accurate guide to levels of activity. When he was party boss of Liaoning, Li Keqiang, strongly tipped as China's next premier, famously said he regarded official output figures as fabrications, and that he relied instead on hard data for power consumption, rail shipments and bank loans as a better guide to the health of the provincial economy.