A popular view among economic commentators is that rich countries face a serious risk of deflation, and should adopt aggressive macroeconomic stimulus policies to ward it off. This column argues that despite similar headline inflation rates, the US, Europe, and Japan in fact face very different macroeconomic conditions. In the US, much of the recent disinflation is attributable to positive supply-side developments. In Europe, an aggressive round of quantitative easing might encourage policymakers to delay the reforms that are necessary to avoid a prolonged Japanese-style malaise.