hysteresis

Bend a piece of metal too far and it does not spring all the way back — it keeps some of the bend permanently. The economy's labour market can behave the same way. After a deep, long recession pushes unemployment up, the rate sometimes refuses to fall back to where it started even after the recession ends. The damage gets baked in. This stubborn failure to return to the old level — where a temporary shock leaves a permanent scar — is called hysteresis.

Hysteresis in unemployment is the idea that a spell of high unemployment can raise the natural rate itself, so that joblessness stays elevated long after the original cause is gone. The mechanisms are concrete. Workers who are unemployed for a long time lose skills, confidence, and professional networks, and employers grow wary of hiring them, so they become structurally unemployable. The long-term unemployed also stop competing actively for jobs, exerting less downward pressure on wages. And firms that close during a slump take their accumulated know-how and equipment with them, which is not rebuilt overnight. A cyclical shock, in other words, can turn into structural damage.

Hysteresis is a powerful and unsettling idea because it overturns a comforting assumption: that recessions are temporary dips the economy automatically recovers from. If hysteresis is real, then letting unemployment stay high — say, by being too slow to stimulate — does lasting harm, not just temporary pain, which strengthens the case for fast, forceful action in downturns. How strong hysteresis is, and in which countries, remains debated, and it is hard to disentangle from a genuinely rising natural rate. But the core warning is taken seriously: do not assume a deep recession leaves no scars.