CAMBRIDGE – Markets nowadays are fixated on how high the US Federal Reserve will raise interest rates in the next 12 months. This is dangerously shortsighted: the real concern ought to be how far it could cut rates in the next deep recession. Given that the Fed may struggle just to get its base interest rate up to 2% over the coming year, there will be very little room to cut if a recession hits.

Fed chair Janet Yellen tried to reassure markets in a speech at the end of August, suggesting that a combination of massive government bond purchases and forward guidance on interest-rate policy could achieve the same stimulus as cutting the overnight rate to minus 6%, were negative interest rates possible. She might be right, but most economists are skeptical that the Fed’s unconventional policy tools are nearly so effective.