A Modified Integer Programming Model for Cleaning Service Scheduling

This paper analyzes the problem faced by a cleaning service company, which records and pays out a large amount of overtime each month. With only one shift per day, the labor force is required to work overtime in order to satisfy the daily work demand. The objective of this paper is to determine the optimum schedule to satisfy the labor requirements at a minimum cost. Tiberwala et al s (1972) single-shift integer programming model for scheduling workers with two consecutive days off per week has been used as the starting point for this research. This paper modifies the model to incorporate two and three shift schedules with one day off per week. Three alternative workforce schedules are then compared and evaluated. The first alternative maintains the traditional one-shift schedule, currently being practiced by the company. The second and third alternatives switch to a two-shift schedule and three-shift schedule, respectively, with overlapping working hours linking the shifts. In comparison to the existing one-shift schedule, the three-shift schedule is expected toproduce savings of 21.4 per cent equivalent to RM23,592 annually.