We investigate the coexistence of formal and informal markets. In formal markets, we assume sellers can publicly advertise their prices and locations, whereas in informal markets, sellers need to trade through bilateral bargaining so as to remain anonymous from the taxing authority. We consider...

`Relative Utilitarianism' (RU) is a version of classical utilitarianism, where each person's utility function is rescaled to range from zero to one. As a voting system, RU is vulnerable to preference exaggeration by strategic voters. The Groves-Clarke Pivotal Mechanism elicits truthful...

The Clarke Pivotal Voting Mechanism (CPVM) elicits truthful revelation of utility functions by requiring any `pivotal' voter to pay a monetary `Clarke tax'. This neglects wealth effects and gives disproportionate power to rich voters. We propose to replace the `Clarke tax' with a lottery,...

We adopt an `epistemic' interpretation of social decisions: there is an objectively correct choice, each voter receives a `noisy signal' of the correct choice, and the social objective is to aggregate these signals to make the best possible guess about the correct choice. One epistemic method is...

Let X be a set of social alternatives, and let V be a set of `votes' or `signals'. (We do not assume any structure on X or V). A `variable population voting rule' F takes any number of anonymous votes drawn from V as input, and produces a nonempty subset of X as output. The rule F satisfies...

Judgement aggregation is a model of social choice where the space of social alternatives is the set of consistent evaluations (`views') on a family of logically interconnected propositions, or yes/no-issues. Unfortunately, simply complying with the majority opinion in each issue often yields a...

The Clarke pivotal mechanism is inappropriate for nonpecuniary public goods, because the assumption of quasilinear utility is invalid, and because the mechanism gives disproportionate influence to wealthier voters. But by introducing a `stochastic' Clarke tax, we can convert any separable...

We develop a model of social choice over lotteries, where people's psychological characteristics are mutable, their preferences may be incomplete, and approximate interpersonal comparisons of well-being are possible. Formally, we suppose individual preferences are described by a...

We propose a mathematical model of `approximate' interpersonal comparisons of well-being, in terms of an incomplete preorder over a space of `psychophysical states'. We argue that this model is consistent with people's intuitions about interpersonal comparisons, intertemporal preferences, and...

We develop a model of preference aggregation where people's psychological characteristics are mutable (hence, potential objects of individual or social choice), their preferences may be incomplete, and approximate interpersonal comparisons of well-being are possible. Formally, we consider...