Compensation Plans for Single- and Multi-Product Salesforces: An Application of the Holmstrom-Milgrom Model

The agency theory approach to understanding salesforce compensation plans is modified to incorporate the intratemporal nature of the salesperson's effort-rate decision, i.e., the decision about the effort-rate at any given point in time potentially depends upon the sales performance up to that point in time in the accounting period. Under the assumptions considered in this paper, Holmstrom and Milgrom (1987) have shown that the optimal compensation plan is linear in total sales over the accounting period. The comparative statics results obtained here corroborate most of the corresponding results in the salesforce compensation literature; moreover, we derive many additional results not available in the literature. It is demonstrated that the commission income as a fraction of total compensation goes up with an increase in the effectiveness of the sales-effort or an increase in base sales. On the other hand, the salary component of the total compensation goes up with increases in uncertainty, absolute risk aversion, marginal cost of production, perceived cost of effort, and/or alternative job opportunities for the salesperson. We provide a discussion of different selling situations where our results may be more or less applicable. An examination of empirical studies already available in the literature reveals support for our findings regarding the relative emphasis of salary and incentive pay in the compensation plan. We also extend the agency theory approach to compare commission rates across products for a multiproduct salesperson. Here it is shown that commission rates are higher for products with higher sales-effort effectiveness, lower levels of uncertainty, and/or lower marginal costs.