Optimal nurse scheduling based on quantitative models of work-related fatigue

Previous nurse scheduling models have mainly focused on managerial constraints to minimize costs. Although some models incorporate nurse preferences and safety guidelines, human factors considerations related to performance of nurses (fatigue) have not been studied extensively. Fatigue has been linked to nursing injuries and medical errors, and shown to be impacted by schedule-related parameters (shift length). Thus, the objective of this article was to develop a nurse scheduling model incorporating quantitative models of fatigue. This model can help a nurse manager to make schedule-related decisions by highlighting trade-offs among many (conflicting) objectives including nurse shift preferences and nurse fatigue levels obtained from two different fatigue models, namely survey-based and circadian function-based fatigue models. The data used in the numerical experiments were obtained from real patient census data and various surveys of nurses working in different hospitals across the United States. Numerical results show that it is possible to obtain Pareto-optimal schedules where the nurse fatigue levels are significantly reduced for a slight decrement in nurse preferences.