There is a joke among Hong Kong investors that the further away from Beijing a commentator may be, the more certain the opinion on China.

By that measure, Argentines should be the most definite in their views. But those in New York and London cannot be far behind, and they are almost unanimous in their negativity. Their view was only reinforced by the Federal Reserve’s apparent reference to China’s slowdown in its decision not to raise interest rates last week. A growing number also refuse to trust Chinese data and prefer their own estimates — resulting in still-lower numbers.

That China’s economy is slowing and its data-collection is in need of improvement is not disputed. Its previous over-reliance on industry is clear and its data analysis is still that of an emerging market. In particular, its consumer data are poor compared with simpler measures of factory output and power generation.