Every Federal Reserve press conference follows the same pattern — in growth and stagnation, in low and high inflation. Reporters ask when the Fed will be satisfied that its tools are working. The poor Fed chair does not really have an answer and says that the central bank is watching carefully, reminding the media that monetary policy has a “long and variable lag” or words to that effect.

This was the format this week when chair Jay Powell talked to the press after another 0.75 percentage point rate rise as the Fed waits for inflation to drop. But it could have just as easily been Janet Yellen or Ben Bernanke. That exquisite phrase “long and variable lag” is a technical-sounding way of saying “we don’t know and we don’t know when we will know”.

Monetary policymakers have been saying this for so long that we have allowed them to launder it into a kind of privilege. They do not have to adapt. They do not have to be creative. Their tools do not have to work. Central bankers remain forever in lag. It is not working now — but it could.