Tabu search in audit scheduling

The problem of audit staff scheduling normally involves auditors with varying efficiencies, and several audit engagements with varying requirements and at different locations. The task of scheduling auditors to the audit tasks becomes more complicated if the scheduler has to accommodate the many real life considerations. The problem, regardless of its size or complexity, has been formulated as a (0–1) integer program. However, the large number of variables and constraints in such a formulation makes the use of exact optimization methods impractical. In this paper, we present a heuristic procedure based on tabu search (TS) and intelligent memory structures for solving this problem. The TS method starts with a feasible schedule generated by a greedy forward dispatching procedure, then through a series of intensification and diversification steps it improves on the initial schedule. The improvement in the value of the objective function is observed interactively. The search can be terminated as the improvement in the value of the objective function stabilizes. Application of the TS method to different audit scheduling problems has led to a consistent and significant improvement in the value of the cost minimization objective function.