The (a)social exam invigilator assignment problem

The invigilator assignment problem provides an assignment of invigilators, also called proctors, to a predetermined exam timetable with given invigilator demand. We provide three problem variants with a focus on invigilator-timeslot preferences and socialization aspects. We prove that the variant with timeslot preferences is polynomially solvable, whereas incorporating socialization aspects makes the problem $$\mathcal{N}\mathcal{P}$$ -hard. Hence, we also provide a heuristic approach and show its effectiveness based on real-life benchmark instances, arising from a case study conducted at Ghent University. Furthermore, we introduce and evaluate artificial instances based on well-known exam timetabling instances from the literature. Finally, we discuss the practical implications and key insights derived from the case study.