A mixed-integer programming model for a single shift hierarchical employee scheduling problem

This paper presents a mixed integer-programming model for single shift and work center scheduling of hierarchical workforce, where employees are arranged into a hierarchy of categories having downward substitutability. An employee that belongs to a category may perform the duties of an employee of a lower category, but not vice versa. A higher category employee has more work qualification and experience than a lower category employee and therefore the former receives a higher compensation than the latter. The weekday and weekend demands of employees for each category are known a priori. The primary objective is to determine an optimal mix of categories of employees that meet the specified demand requirements of employees of the different categories. The secondary objective is to meet, to the extent possible, the selected employee preference on off-days. We use CPLEX (version 9.0) to solve the developed model based on a set of ten test problems representing various work scenarios