This volume brings together and expands on a body of research that I
began in the early 1960s and have continued up to the present. It deals
mainly with shiftwork-work that is performed during other than normal
daytime hours. Shiftwork is a characteristic of economic life in the
United States and abroad that has increased in importance over the
years; according to the Bureau of Labor Statistics, one out of five
full-time and part-time employees in the United States works on shifts.
My interest in this field concerns fixed capital, specifically, changes
in weekly hours worked by capital over long periods of time, and the
signifi- cance of those changes in the measurement oflong-run
productivity change. In studies of growth, the measurement of capital
input-by capital stocks or the services yielded by those
stocks-typically makes no allowance for the changing hours worked by
capital. Capital services are assumed to be propor- tional to the
stocks. Consequently, in analyses of output growth in a growth-
accounting framework, the effect of longer capital hours is a component
of multifactor or total factor productivity growth.