Many scarce public resources are allocated at below-market-clearing prices and sometimes for free. Such “nonmarket” mechanisms sacrifice some surplus, yet they can potentially improve equity. We develop a model of mechanism design with redistributive concerns. Agents are characterized by a privately observed willingness to pay for quality, a publicly observed label, and a social welfare weight. A market designer controls allocation and pricing of a set of objects of heterogeneous quality and maximizes the expectation of a welfare function. The designer does not directly observe individuals’ social welfare weights. We derive structural insights about the form of the optimal mechanism, leading to a framework for determining how and when to use nonmarket mechanisms.

We propose an economic framework for determining the optimal allocation of a scarce supply of vaccines that become gradually available during a public health crisis, such as the COVID-19 pandemic. Agents differ in observable and unobservable characteristics, and the designer maximizes a social welfare function over all feasible mechanisms—accounting for agents’ characteristics, as well as their endogenous behavior in the face of the pandemic. The framework emphasizes the role of externalities and incorporates equity as well as efficiency concerns. Our results provide an economic justification for providing vaccines immediately and for free to some groups of agents, while at the same time showing that a carefully constructed pricing mechanism can improve outcomes by screening for individuals with the highest private and social benefits of receiving the vaccine. The solution casts light on the classic question of whether prices or priorities should be used to allocate scarce public resources under externalities and equity concerns.