Learning about fiscal policy and the effects of policy uncertainty

In this paper we ask how uncertainty about fiscal policy affects the impact of fiscal policy changes on the economy when the government tries to counteract a deep recession. The agents in our model are uncertain about the conduct of fiscal policy and act as econometricians by estimating fiscal policy rules that might change over time.We find that assuming that agents are not instantaneously aware of the new fiscal policy regime in place leads to substantially more volatility in the short run and persistent differences in average outcomes. We highlight issues that can arise when a policymaker wants to announce a policy change. From a methodological perspective, we introduce a novel way to model learning in the face of discrete policy changes.