Where Is the Natural Rate? Rational Policy Mistakes and Persistent Deviations of Inflation from Target

Empirical research has shown that there is large uncertainty concerning the value of the natural rate of unemployment at any point in time. I incorporate this feature in a model of monetary policy where the policymaker targets an inflation rate and the natural rate of unemployment and solve for the optimal policy. Two interesting results emerge. First, under a realistic shock profile, the model generates long-lasting deviations of inflation from target, providing an alternative (but also a complement) to the popular Barro-Gordon framework. Second, the economy exhibits large inflation persistence and can have very rich inflation dynamics. The model is able to account for approximately one third of the increase in inflation in the United States in the late 1970s, and suggests an explanation for the low inflation of the late 1990s. Moreover, I present empirical evidence for the United States and other countries that support the model including a new empirical finding: across countries there is a positive statistical relation between the persistence of unemployment and the persistence of inflation.