Optimal Contract Under Asymmetric Information About Fairness

Problem definition: To improve the poor performance of supply chains caused by misaligned incentives under the wholesale price contract, theory proposes coordinating contracts. However, a common finding of experimental studies testing such contracts is that they tend to yield only a marginal, if any, performance improvement over wholesale pricing. These studies identify several behavioral factors that are at play but none accounted for by the theory proposing coordinating contracts. Among them, identified as the single most detrimental for the supply chain performance, is incomplete information about preferences for fairness causing contract rejections. Can the supply chain performance be improved with a contract designed allowing for this type of information asymmetry? What does this contract (mechanism) look like? Academic/practical relevance: The extant research characterized the optimal contracting mechanisms for such important practical cases as the suppliers’ private information about production cost or the retailers’ private information about the end customer demand. The present study addresses the gap in another important practical case: when the source of information asymmetry is the private information about preferences for fairness. Methodology: The underlying research method is mechanism design. Results: We prove that the optimal mechanism consists of a single contract positioned on the Pareto frontier and characterize the optimal profit split between the supplier and the retailer. We show that, under a wide range of preferences for fairness, the efficiency loss because of private information is strictly positive, but exceptions are possible. We also show that the optimal mechanism can be implemented with a variety of commonly used in practice and widely studied in academic literature contracts, including the minimum order quantity and the two-part tariff ones. Managerial implications: We establish a direct link between a large volume of theoretical and empirical literature on social preferences with the research on supply chain contracts. Because rejections that are because of incomplete information are an important cause of contract inefficiency observed in the laboratory, managers should avoid take it or leave it offers when they negotiate contracts. Instead, the bargaining process should be geared toward discovering the extent of the fairness preferences of the contracting parties.