Debt is the crux of advanced economies’ current policy debates. Some argue for fiscal expansion to avoid recession and deflation. Others claim that you can’t solve a debt-created problem with more debt. This column explains the core logic of a new model by Eggertsson and Krugman in which debt shocks and policy reactions can be examined. Relying on heterogeneous agents, the model naturally produces the paradox of thrift but also finds new supply-side paradoxes, those of toil and flexibility. The model suggests that most economists have been misthinking the issues and that actual policy in the US and EU is misguided.

The financial crisis has brought large fiscal deficits and soaring public debt. A switch to tight fiscal policy risks throttling the recovery, but continuing deficits are spooking markets. This column argues the obvious solution is to promise future fiscal rectitude and stick with the current expansionary policies in the near term. This requires independent fiscal policy committees to institutionalise fiscal transparency and restore credibility to governments’ long-term public finances.