Incentive Contracts in Serial Stochastic Projects

In this paper we propose an incentive payment contract for stochastic projects defined by a series of stages or tasks that are outsourced to independent subcontractors. Projects defined by sequentially completed independent stages are common in new product development and other high-risk projects. Our goal is to maximize the client's expected discounted profit. Our proposed contract reflects the convex time-cost trade-off that is well known in the project scheduling literature. We show that this type of contract dominates a fixed price contract with respect to expected client's profit and schedule performance, regardless of payment timing considerations. Using a piecewise linear approximation, we show that our contract is a generalization of an incentive/disincentive contract that is frequently used in practice. We show how our contract can be used to find the optimal due date and penalties/bonuses in an incentive/disincentive contract. We compare this contract with several variations and discuss implications for both the client and subcontractors.