Concerns about deflation – falling prices of goods and services – are rooted in the view that it is very costly. This column tests the historical link between output growth and deflation in a sample covering 140 years for up to 38 economies. The evidence suggests that this link is weak and derives largely from the Great Depression. The authors find a stronger link between output growth and asset price deflations, particularly during postwar property price deflations. There is no evidence that high debt has so far raised the cost of goods and services price deflations, in so-called debt deflations. The most damaging interaction appears to be between property price deflations and private debt.