We study a general screening model that encompasses a health insurance market in which consumers have multiple dimensions of private information and a price-setting insurer (e.g., a monopolist or a social planner) offers vertically differentiated contracts. We combine theory and empirics to...

We define and explore no‐upward‐crossing (NUC), a condition satisfied by every parameterized family of distributions commonly used in economic applications. Under smoothness assumptions, NUC is equivalent to log‐supermodularity of the negative of the derivative of the distribution with...

Consider an agent who can costlessly add mean‐preserving noise to his output. To deter such risk‐taking, the principal optimally offers a contract that makes the agent's utility concave in output. If the agent is risk‐neutral and protected by limited liability, this concavity constraint...

We study procurement auctions in which, as is common in practice, a group of sellers (incumbents, qualified bidders) is given an advantage, based, for example, on better reliability, quality, or incumbency status. We show conditions under which for any given first price handicap auction, there...

We provide a new class of counter-examples to existence in a simple moral hazard problem in which the first-order approach is valid. In contrast to the Mirrlees example, unbounded likelihood ratios on the signal technology are not central. Rather, our examples center around the behavior of the...

We show existence of equilibria in distributional strategies for a wide class of private value auctions, including the first general existence result for double auctions. The set of equilibria is invariant to the tie-breaking rule. The model incorporates multiple unit demands, all standard...