Is still more tightening in store? Most observers think the answer is “yes,” but the Fed is leaving its options open. Its most recent projections, released immediately after its December meeting, hint at the possibility of as many as ten more quarter-point increases over the next three years—or perhaps none at all. So what will actually happen?
The wonkiest number in all of economics
What actually happens will depend , in large part, on what may be the wonkiest number in all of economics—the Nairu. Nairu stands for Non-Accelerating Inflation Rate of Unemployment—such a mouthful that no one ever says it out loud. Often, it is spelled out as an acronym, NAIRU, but increasingly, it is written as an actual word, with only the first letter capitalized. In the 1960s, Milton Friedman used the more civilized term, natural rate of unemployment. Today, many economists treat “Nairu” and “natural rate” as synonyms.
The basic idea behind the Nairu is simple. It is widely accepted that as the economy moves through the business cycle from recession to expansion to boom, shortages develop in labor and product markets that put upward pressure on prices and wages. The Nairu is supposed to capture the sweet spot—the lowest level to which the unemployment rate can safely fall before inflation starts to accelerate.
The Nairu is a natural fit with the Fed’s statutory objectives for the conduct of monetary policy. Under its so-called dual mandate, the Fed is supposed to aim for “maximum employment and stable prices.” The Nairu captures both parts of the dual mandate, being the maximum employment (or minimum unemployment) that is consistent with prices that are stable in the sense that the inflation rate does not accelerate from month to month.
In order actually to implement its dual mandate, the Fed needs to fill in some numbers. In recent years, it has maintained an inflation target of 2 percent per year, as measured by the personal consumption expenditure (PCE) index published quarterly by the Bureau of Economic Analysis. Putting a number on the Nairu, however, has posed more of a challenge.
Why the Nairu is so hard to pin down
Back in the 1960s, things seemed simpler. Consider the following chart, which shows the pattern of unemployment and inflation that prevailed during the Kennedy-Johnson years, 1960-1969:
The points in this chart fit closely around a trendline that economists call a Phillips curve—a curve that shows an inverse relationship between inflation and unemployment over the course of the business cycle. Taken literally, the value of the Nairu would be 6.7 percent, the level at which inflation started to accelerate after reaching its low of 0.6 percent in the fourth quarter of 1961. If, instead, we interpret the Nairu as the value of unemployment beyond which inflation begins to rise above the 2 percent target, then the chart suggests an unemployment target of about 4.3 percent.