Optimised break scheduling vs. rest breaks in collective agreements under fatigue and non preemption

Abstract

Collective agreements provide all workers with identical break schedules, irrespective of their individual differences in susceptibility to fatigue and recovery speed. In addition, companies tend to limit breaks which is also detrimental to productivity. We consider workers performing a repetitive task, each endowed with an individual fatigue and recovery function. Fatigue slows down the unit processing time which can be restored by appropriate breaks, therefore allowing for the daily production amount to be optimised. The optimised production of each worker can actually be reached for a multitude of break schedules. We therefore develop an algorithm that lists all possible break schedules (enumeration), and selects those leading to the maximum daily output, and the maximum welfare. Welfare is defined by the break duration and their timing flexibility, since we allow breaks to be also taken at the beginning or end of the workday, enabling workers to spend less time in the workplace. Having a variety of schedules would help in meeting at best the workers’ preferences and facilitate a consensus on a specific schedule between managers and workers. The resulting optimised break schedules are compared with common break practices in collective agreements so as to assess their impact on productivity and on worker’s welfare. None of the break scheduling models in the literature considers the option of leaving the workplace earlier, which is nevertheless highly appreciated by workers, nor do these models provide a variety of optimised break schedules to best accommodate workers’ preferences.