The impact of reserve duties on the robustness of a personnel shift roster: An empirical investigation

In personnel scheduling, a duty roster is typically constructed under the assumption of a deterministic model. However, organisations operate in a stochastic environment and the conjectures made about the demand for staff and the availability of employees may prove to be insufficient to represent reality. In order to anticipate these unexpected events, we investigate the impact of introducing reserve duties in the medium-term personnel shift roster. Reserve duties are scheduled by enforcing specific staffing requirements and/or time-related constraints that consider reserve duties only. We propose a three-step methodology that imitates the workforce management process to evaluate the delivered robustness in terms of the actual performance. After a personnel roster is constructed, unexpected events are simulated and an optimisation model determines the required adjustments to balance supply and demand. Detailed computational experiments are presented to provide managerial insights into different strategies to schedule reserve duties.