Every extra point of unemployment costs an economy roughly two points of output

In 1962, economist Arthur Okun spotted a stable pattern in US data: when unemployment rises by one percentage point, GDP tends to fall by about two percentage points below its potential. The relationship, now called Okun's law, gives policymakers a rough rule of thumb for how much growth a drop in joblessness is worth. The exact ratio drifts across decades and countries, but the direction never has.

— Arthur M. Okun, Potential GNP: Its Measurement and Significance — Proceedings of the Business and Economics Statistics Section, American Statistical Association, 1962