Robust monetary policy under model uncertainty and inflation persistence

In this paper, we examine the inflation persistence puzzle by applying the robust control approach of Hansen and Sargent (2008). In line with the literature suggesting that inflation persistence may be affected by the monetary policy design and its institutional characteristics, we find that inflation persistence is positively related to the central bank's preference for model robustness. In effect, model uncertainty and robust decision making may be considered as a mechanism generating inflation persistence, for a given non-zero degree of autocorrelation in supply-side shocks. Further, the policy implication is that the central bank's monetary policy under model uncertainty renders, in terms of the sacrifice ratio, the output-cost of inflation stabilization more important.

► We revisit the optimal monetary policy in a framework of inflation persistence. ► A robust monetary policy is adopted to incorporate model uncertainty. ► A stronger preference for model robustness increases inflation persistence. ► Policymakers should gauge high degrees of inflation persistence when designing policy.