A hierarchical procedure for multi-skilled sales force spatial planning

Marketing and sales comprise an important part of a company's core processes. We study this core component in a very large corporation in the process industry. This company has thousands of employees worldwide involved in sales and marketing activities. The optimal utilization of this large workforce is rigorously analyzed in this paper. We develop a hierarchical procedure including a sequence of mathematical models to address workload determination and sales force planning within the company. In particular, our sequence of models determines: (a) the optimal number of visits to each of the existing customers with the goal of retaining them; (b) the optimal number of employees with different kinds of skills for satisfying the workload obtained using model (a) including the time to hunt for new customers; and (c) the optimal way of providing the workforce calculated in part (b) (i.e., optimal strategies for hiring, relocation or dismissal of current workforce). Moreover, we face some nonlinear constrained integer programming problems in our sequence of mathematical models which are not easily solved by commercial software. We develop our own efficient methods for solving such problems optimally.