I study a model of strategic communication between an uninformed Receiver and an informed but upwardly biased Sender. The Sender bears a cost of lying, or more broadly, of misrepresenting his private information. The main results show that inflated language naturally arises in this environment, where the Sender (almost) always claims to be of a higher type than he would with complete information. Regardless of the intensity of lying cost, there is incomplete separation, with some pooling on the highest messages. The degree of language inflation and how much information is revealed depend upon the intensity of lying cost. The analysis delivers a framework to span a class of cheap-talk and verifiable disclosure games, unifying the polar predictions they make under large conflicts of interest. I use the model to discuss how the degree of manipulability of information can affect the trade-off between delegation and communication.

Why do office-motivated politicians sometimes espouse views that are non-congruent with their electorate’s? Can non-congruent statements convey any information about what a politician will do if elected, and if so, why would voters elect a politician who makes such statements? Furthermore, can electoral campaigns also directly affect an elected official’s behaviour? We develop a model of credible “cheap talk”—costless and non-binding communication—in elections. The foundation is an endogenous voter preference for a politician who is known to be non-congruent over one whose congruence is sufficiently uncertain. This preference arises because uncertainty about an elected official’s policy preferences generates policymaking distortions due to reputation/career concerns. We show that cheap talk can alter the electorate’s beliefs about a politician’s policy preferences and thereby affect the elected official’s behaviour. Informative cheap talk can increase or decrease voter welfare, with a greater scope for welfare benefits when reputation concerns are more important.

This paper studies a model of long-term contracting for experimentation. We consider a principal–agent relationship with adverse selection on the agent’s ability, dynamic moral hazard, and private learning about project quality. We find that each of these elements plays an essential role in structuring dynamic incentives, and it is only their interaction that generally precludes efficiency. Our model permits an explicit characterization of optimal contracts.

An agent’s preferences depend on an ordered parameter or type. We characterize the set of utility functions with single-crossing differences (SCD) in convex environments. These include preferences over lotteries, both in expected utility and rank-dependent utility frameworks, and preferences over bundles of goods and over consumption streams. Our notion of SCD does not presume an order on the choice space. This unordered SCD is necessary and sufficient for “interval choice” comparative statics. We present applications to cheap talk, observational learning, and collective choice, showing how convex environments arise in these problems and how SCD/interval choice are useful. Methodologically, our main characterization stems from a result on linear aggregations of single-crossing functions.