Glossary · approach
Fatigue Constraint
A scheduling rule that limits worker fatigue in safety-critical roles — minimum rest, max consecutive nights, weekly hours, weekend balance.
Fatigue RuleRest ConstraintConsecutive Night LimitPatient-Safety Constraint
Fatigue constraints are the family of hard or soft scheduling rules designed to limit worker fatigue in healthcare or other safety-critical roles. They include minimum rest between consecutive shifts (typically 11 hours from night to morning), maximum consecutive night shifts (typically 3 or 4), maximum weekly working hours, weekend distribution balance, and minimum recovery days after night runs. The European Working Time Directive provides one regulatory baseline; collective agreements often tighten the rules. Violations of fatigue constraints are correlated with medical errors, workplace accidents and staff turnover. In the Nurse Rostering Problem (NRP) literature (Burke, De Causmaecker, Vanden Berghe and Van Landeghem 2004; Burke, Curtois, Qu and Vanden Berghe 2010), fatigue constraints are typically modelled as hard constraints — a schedule that breaches them is infeasible. Generic shift-scheduling engines often treat only the weekly hour cap; healthcare-grade engines must enforce the full family.
Örnek
An ICU nurse cannot work a 4th consecutive night shift; after 3 consecutive nights, at least one rest day is required before the next shift. The shift-to-shift gap must be 11 hours minimum. These rules are hard constraints in the rostering MIP.