The cyclical and secular behaviour of the labour input: Comparing efficiency units and hours worked
构建了考虑劳动力质量差异的月度效率单位序列，并与未调整的工作时长比较，发现两者在周期性波动上差异不大，但长期趋势截然不同：人均工作时长显著上升，而人均效率单位无趋势。
Abstract A monthly labour input series designed to correct for the fact that all hours worked are not of the same quality is constructed and its properties compared with unadjusted hours worked. This efficiency units series is constructed from BLS data on hours worked and earnings by age and sex. The cyclical fluctuations displayed by the efficiency units series are smaller on average than those displayed by hours worked, although the difference is not large. However, the secular behaviour of the series is quite different: hours worked per capita displays a significant positive trend while efficiency units per capita does not.