The impact of overtime as a time-based proactive scheduling and reactive allocation strategy on the robustness of a personnel shift roster

Abstract

The workforce size and the overtime budget have an important impact on the total personnel costs of an organisation. Since the personnel costs represent a significant fraction of the operating costs, it is important to define an appropriate hiring and overtime policy. Overtime is defined as an extension of the daily working time or the total working time over the planning period. In this paper, we make the distinction between scheduled and unscheduled overtime when we define the overtime policy. Scheduled overtime is proactively assigned in the baseline personnel roster whereas unscheduled overtime is allocated as a reactive strategy to overcome operational disruptions. The hiring and overtime policy undoubtedly influence the robustness included in a personnel roster, i.e., the capability of an organisation to deal with roster disruptions at an acceptable cost. In this paper, we investigate the trade-off between the hiring budget and the overtime budget and the way overtime should be allocated in the personnel management process. The latter comprehends a trade-off between the proactive scheduling of overtime and the reservation of overtime to balance supply and demand in response to operational variability. Insights are obtained by exploring three different strategies to compose a personnel shift baseline roster. We verify the robustness of each of these strategies by applying a three-step methodology that thrives on optimisation and simulation and we formulate some managerial guidelines to define an appropriate hiring and overtime policy

Quantifying and enforcing robustness in staff rostering

“…Two general approaches currently exist for introducing robustness in staff rosters: those focusing on horizontal robustness and those focusing on vertical robustness. Horizontal robustness may be obtained by extending shift durations or by permitting overtime to compensate for employee shortages (Ingels and Maenhout, 2018). Vertical robustness is introduced through different types of buffers which manage uncertainty of demand and capacity through the use of surplus resources.…”

Competence-oriented project team planning – university case study

“…For example, Ingels and Maenhout (2015) define capacity buffers by setting a percentage above the expected staffing requirements that accounts for specific time constraints. Another type of buffer is overtime, which increases efficiency in specific time intervals (Ingels & Maenhout, 2018). Ionescu and Kliewer (2011) and Shebalov and Klabjan (2006) have focused on maximizing the number of crew swapping options for aircraft crew planning (Dück et al, 2012).…”

“…Reactive strategies can also be improved by extending daily work hours and total work hours in the entire planning horizon (Easton & Rossin, 1997;Ingels & Maenhout, 2018).…”

Preface

“…In "A list-scheduling heuristic for the short-term planning of assessment centers" (Zimmermann and Trautmann 2017), the authors investigate a novel planning problem that utilises a multi-pass list-scheduling heuristic for scheduling candidates to undertake a set of tasks so that they can be evaluated. The paper "The impact of overtime as a time-based proactive scheduling and reactive allocation strategy on the robustness of a personnel shift roster" (Ingels and Maenhout 2017) investigates the trade-off between a hiring budget and an overtime budget and the way overtime should be allocated in the personnel management process. The authors apply a three-step methodology, resulting in the formulation of managerial guidelines for hiring and overtime policy.…”