THE SLOWDOWN in productivity growth in the U.S. economy that has
occurred in the past ten years has been the subject of several careful
studies accounting for growth.' Although these studies differ in methodology
and emphasis, their overall conclusion is clear. They attribute most
of the slowdown in the growth of average labor productivity to a decline
in the growth rate of total factor productivity-that is, to developments
other than changes in the quantities of capital and labor used in production.