A typical factory can be operated for eight, sixteen, or twenty-four hours per day by making use of one, two, or three shifts of workers. The decisions with respect to the number of shifts are not made, we believe, entirely by accident but depend in large part on economic considerations. Only fairly recently have economists given serious attention to explanations of what these considerations are and how they affect shift-work behavior.

The topic is of considerable intellectual interest in its own right. Moreover, the theory of production is seriously incomplete without a thorough treatment of capital utilization. But the subject should also be of interest to a rather wide audience of economists and other social scientists for at least three reasons. First, the lives of workers engaged in permanent night-work or rotating shift-work are typically adversely affected either by the disruption of biological rhythms or by the reduction in contact with family and community. Second, and on the positive side, more intensive utilization of the capital stock normally increases the output available to the society, both in the present and in the future; the additional output makes possible increased consumption by capitalists or workers or both. Third, a preliminary view of the matter suggests that the distribution of the increased output would be especially favorable to the workers, in the form of higher wages or more jobs.