@techreport{NBERw14566,
 title = "The Timing of Labor Demand",
 author = "Ana Rute Cardoso and Daniel S. Hamermesh and José Varejão",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "14566",
 year = "2008",
 month = "December",
 URL = "http://www.nber.org/papers/w14566",
 abstract = {We examine the timing of firms' operations in a formal model of labor demand.  Merging a variety of data sets from Portugal from 1995-2004, we describe temporal patterns of firms' demand for labor and estimate production-functions and relative labor-demand equations. The results demonstrate the existence of substitution of employment across times of the day/week and show that legislated penalties for work at irregular hours induce firms to alter their operating schedules.  The results suggest a role for such penalties in an unregulated labor market, such as the United States, in which unusually large fractions of work are performed at night and on weekends.},
}