The equivalence of robustly optimal targeting rules and robust control targeting rules: an extension

Walsh (2004) demonstrated that the robustly optimal targeting rule of Giannoni and Woodford (2003a, 2003b) and the targeting rule of a policy maker concerned with robustness in the sense of Hansen and Sargent (2004) were identical in a purely forward-looking new Keynesian model. In this note, I first show that the equivalence result extends to a new Keynesian model with inflation inertia (Woodford 2003). Then, this equivalence is shown to apply in a wide class of models.