Why Has the Cyclicality of Productivity Changed? What Does It Mean?
研究发现美国全要素生产率在1980年代中期后周期性减弱，劳动生产率的周期性甚至反转，主要原因是要素利用率（资本工作周和劳动努力）的波动减小。
US labor and total factor productivity have historically been procyclical—rising in booms and falling in recessions. After the mid-1980s, however, total factor productivity became much less procyclical with respect to hours while labor productivity turned strongly countercyclical. We find that the key empirical “fact” driving these changes is reduced variation in factor utilization—conceptually, the workweek of capital and labor effort. We discuss a range of theories that seek to explain the changes in productivity's cyclicality. Increased flexibility, changes in the structure of the economy, and shifts in relative variances of technology and “demand” shocks all play key roles.