The NAIRU in Theory and Practice
讨论自然失业率（NAIRU）的概念，分析其在商业周期理论中的作用、测量困难以及为何在1990年代美国下降，最可能的解释是生产率增长加速。
This paper discusses the NAIRU—the non-accelerating inflation rate of unemployment. It first considers the role of the NAIRU concept in business cycle theory, arguing that this concept is implicit in any model in which monetary policy influences both inflation and unemployment. The exact value of the NAIRU is hard to measure, however, in part because it changes over time. The paper then discusses why the NAIRU changes and, in particular, why it fell in the United States during the 1990s. The most promising hypothesis is that the decline in the NAIRU is attributable to the acceleration in productivity growth.