Sometimes statistics don’t behave as predicted. Take the thorny issue of US-China trade and Donald Trump.

Earlier this year, the US president expressed fury about the size of America’s bilateral trade deficit with China and imposed escalating tariffs on $250bn worth of Chinese imports. The assumption inside the White House was that this would cause the deficit to shrink, since American companies would produce more goods at home and/or find ways to avoid costlier imports.

But that theory has not played out — or not yet. Far from it. Last week the US government released data showing that America’s deficit in traded goods with China jumped 4.3 per cent in September to a seasonally adjusted level of $37.4bn, a record high. This was due to a thumping 8 per cent rise in American imports from China. Exports, however, remained broadly flat.