I would also suggest that the optimal inflation rate is not likely to remain constant over time. An alternative, which would recognize that the inflation target should not necessarily be constant, is an inflation range with an adjustable inflation target. Within this framework, one could think of our inflation goal as defined by two components: A range of inflation rates that policymakers would find acceptable across many economic circumstances, and a medium-term goal within that range that policymakers would set, perhaps year by year, depending on specific economic circumstances.
In my view, adopting an inflation range that allows for movement in the effective medium-run inflation goal might be a helpful addition to the Fed’s monetary policy framework. An inflation range that allows some movement in the inflation target, depending on economic fundamentals, would be treating the Fed’s inflation goal more like the natural rate of unemployment, where we recognize that the natural rate will shift over time with demographic and other workforce characteristics.
Of course, the advantages of greater inflation target flexibility would likely be partly offset by some costs. For instance, it is likely that such flexibility would generate more uncertainty about inflation in the medium to long run, since we cannot know for sure how long productivity and demographic trends would persist.7 However, if we set the range to – for example – 1.5 to 3.0 percent, and were successful in keeping inflation mostly in that range, this would represent a set of inflation outcomes that are similar to those the U.S. has experienced over the past 20 years.
One way to avoid periods of prolonged low interest rates would be to alter the inflation target in response to changes in our estimates of real interest rates – estimates that have been changing of late. This would make inflation, like the natural unemployment rate, a target that could vary over time. If, for example, the monetary policy framework set an inflation range of, say 1.5 to 3.0 percent, the FOMC could vary its medium-term inflation target to be high, low, or in the middle of the range depending on economic factors that the Committee could determine at the beginning of each year. For example, in the current environment, with low population growth and low productivity growth, policy could move even more gradually to remove accommodation, and allow inflation to be somewhat higher in its range. Should the labor force or productivity grow more quickly, the Committee could seek to gradually reduce the inflation target within its range.
An inflation range with an adjustable medium-run inflation goal is one way to address such concerns, but there are a variety of alternative frameworks also worth considering.18 In my view, we are approaching a time when a comprehensive reconsideration of the monetary policy framework is likely warranted, given the experience of the past 10 years. Any change we make should be designed to provide policymakers with the flexibility to set monetary policy appropriately as key features of the economy change, as they have repeatedly over U.S. economic history.