سیاست پولی نامتقارن و مرز مؤثر پایین

We use the canonical New Keynesian model to study optimal discretionary policy when the nominal interest rate is constrained by the effective lower bound (ELB). We show that policymakers who seek to minimize a (symmetric) quadratic loss function involving deviations of inflation and output from targets will achieve an average inflation rate below target due to the contractionary effects associated with hitting the ELB. We also characterize optimal discretionary policy for policymakers who view output losses as asymmetric: they place weight on the output gap when output is below potential but place little or no weight on the gap when output is above potential. In comparison to optimal policy using the symmetric loss function, the average inflation rate is higher and closer to the central banks target. Moreover, in response to contractionary demand shocks that push the nominal interest rate to the effective lower bound, policymakers with an asymmetric loss function adopt a policy rate path that remains at the ELB longer but eventually rises more quickly than the path adopted by a policymaker with a symmetric loss function.