Average Inflation Targeting and the Interest Rate Lower Bound

Assigning a discretionary central bank a mandate to stabilize an average inflation rate - rather than a period-by-period inflation rate - increases welfare in a New Keynesian model with an occasionally binding lower bound on nominal interest rates. Under rational expectations, the welfare-maximizing averaging window is infinitely long, which means that optimal average inflation targeting (AIT) is equivalent to price level targeting (PLT). However, AIT with a finite, but sufficiently long, averaging window can attain most of the welfare gain from PLT. Under boundedly-rational expectations, if cognitive limitations are sufficiently strong, the optimal averaging window is finite, and the welfare gain of adopting AIT can be small