Membership design involves allocating an economic good whose value to any individual depends on who else receives it. We introduce a framework for optimal membership design by combining an otherwise standard mechanism-design model with allocative externalities that depend flexibly on agents' observable and unobservable characteristics. Our main technical result demonstrates that the optimal mechanism offers distinct membership tiers—differing in prices and level of access—and that the number of membership tiers is increasing in the complexity of the externalities. This insight may help explain a number of mechanisms used in practice to sell membership goods, including musical artists charging below-market-clearing prices for concert tickets, certain admission procedures used by colleges concerned about the diversity of the student body, heterogeneous pricing tiers for access to digital communities, and the use of vesting and free allocation in the distribution of network tokens.

The assignment of property rights has important implications for both economic efficiency and the distribution of surplus within society. Consequently, there are trade-offs associated with the design of these rights. Awarding a full property right over an economic resource incentivizes the owner to make efficient investment decisions related to its use. However, when transaction costs are present, strong property rights may inhibit the future reallocation of economic resources to agents who can utilize them most efficiently. Moreover, the assignment of property rights may give rise to market power or conflict with society's distributive objectives. This raises a natural question: How should property rights be optimally designed?

Public agencies are often tasked with allocating scarce resources (such as public housing or financial aid) to a target population. In many such cases, the goal is to maximize social welfare, which requires identifying agents who have the highest social value for the resource. The challenge is that while public agencies may be able to access some data about potential beneficiaries (for example, through means testing), they generally lack information necessary to achieve perfect targeting. When monetary transfers are unavailable or ineffective in targeting, public agencies often rely on "ordeals" instead. Natural examples include standing in line, filing out complicated forms, dealing with "red tape," waiting, visiting an office at an inconvenient time, or traveling to a registration site. But what makes one costly screening device better than another?

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.

We study the design of mechanisms involving agents that have limited strategic sophistication. We define a mechanism to be simple if—given the assumed level of strategic sophistication—agents can determine their optimal strategy. We examine whether it is optimal for the mechanism designer who faces strategically unsophisticated agents to offer a simple mechanism. We show that when the designer uses a mechanism that is not simple, while she loses the ability to predict play, she may nevertheless be better off no matter how agents resolve their strategic confusion.

Even when global income redistribution is not feasible, market designers can seek to mitigate inequality within individual markets. If sellers are systematically poorer than buyers, for example, they will be willing to sell at relatively low prices. Yet a designer who cares about inequality might prefer to set higher prices precisely when sellers are poor -- effectively, using the market as a redistributive tool. In this paper, we seek to understand how to design goods markets optimally in the presence of persistent inequality. Using a mechanism design approach, we find that redistribution through markets can indeed be optimal. When there is substantial inequality across sides of the market, the designer uses a tax-like mechanism, introducing a wedge between the buyer and seller prices, and redistributing the resulting surplus to the poorer side of the market via lump-sum payments. When there is significant within-side inequality, meanwhile, the designer imposes price controls even though doing so induces rationing.

No abstract available.