We examine the expectational stability (E-stability) of the rational expectations equilibrium (REE) in a simple New Keynesian model in which private agents engage in adaptive learning by referring to the central bank's forecast. In this environment, to satisfy the E-stability condition, the central bank must respond more strongly to the expected inflation rate than the so-called Taylor principle suggests. On the other hand, the central bank's strong reaction to the expected inflation rate raises the possibility of indeterminacy of the REE. In considering these problems, a robust policy is to respond to the current inflation rate to a certain degree.
Keywords: Adaptive Learning; E-stability; New Keynesian Model; Monetary Policy; Taylor principle
Views expressed in the paper are those of the authors and do not necessarily reflect those of the Bank of Japan or Institute for Monetary and Economic Studies.