We show that if policy-makers compute the optimal unconstrained interest-rate rule within a Taylor-type class, they may be led to rules that generate indeterminacy and/or instability under learning. This problem is compounded by uncertainty about structural parameters since an optimal rule that...

We examine global dynamics under infinite-horizon learning in New Keynesian models where the interest-rate rule is subject to the zero lower bound. The intended steady state is locally but not globally stable. Unstable deflationary paths emerge after large pessimistic shocks to expectations. For...

We study how the use of judgment or "add-factors" in forecasting may disturb the set of equilibrium outcomes when agents learn using recursive methods. We isolate conditions under which new phenomena, which we call exuberance equilibria, can exist in a standard self-referential environment....

We study how the use of judgment or "add-factors" in macroeconomic forecasting may disturb the set of equilibrium outcomes when agents learn using recursive methods. We examine the possibility of a new phenomenon, which we call exuberance equilibria, in the New Keynesian monetary policy...

The authors consider inflation and government debt dynamics when monetary policy employs a global interest rate rule and private agents forecast using adaptive learning. Because of the zero lower bound on interest rates, active interest rate rules are known to imply the existence of a second,...