Core Concepts
Designing incentive-compatible batching mechanisms can improve the efficiency of allocating scarce resources, such as organs, by balancing the planner's need to learn from agents' private information and the agents' strategic incentives.
Abstract
The paper considers the problem of offering a scarce object with a common unobserved quality to strategic agents in a priority queue. Each agent has a private signal about the quality of the object and observes the decisions made by other agents.
The key insights are:
Under the widely-used first-come-first-served sequential offering mechanism, herding behavior emerges: initial rejections create an information cascade resulting in inefficient waste.
To address this issue, the authors introduce a class of batching mechanisms. Agents in each batch report whether they would be willing to accept or reject the object based on their private signals and prior information. If the majority opts to accept, the object is randomly allocated within that batch.
The authors prove that suitable batching mechanisms are incentive-compatible and improve efficiency. A key property is the gradual increase of the batch size after each failed allocation, chosen to elicit as much information as possible without distorting the agents' incentives to report truthfully.
The authors show that there always exists an incentive-compatible batching mechanism that improves correctness (the probability of a correct allocation) compared to the sequential offering mechanism, as long as the private signals are more informative than the common prior belief.
Simulations illustrate that the correctness of the batching mechanisms increases with the number of batches and decreases as the prior becomes more optimistic, but improves as the signal precision increases.
The results can inform policy and decision-making in critical resource allocation domains, such as deceased donor kidney allocation, where herding behavior may lead to high discard rates.
Stats
More than 25% of kidneys recovered from deceased donors were discarded in 2023.
The Kidney Donor Risk Index (KDRI) is used in the US deceased donor kidney allocation process.
Quotes
"Herding occurs when refusals by preceding patients in the queue trigger a self-reinforcing chain of subsequent declines."
"Failing to allocate the object in a given batch results in a more pessimistic belief about the object quality. Therefore the mechanism increases the batch size to ensure that the object is allocated only if sufficiently many agents receive positive signals."