When is the weighted sum of quasi-concave functions quasi-concave? We answer this, extending an analogous preservation of the single-crossing property in QS: Quah and Strulovici (2012). Our approach develops a general preservation of n-crossing properties, applying the variation diminishing...

We introduce a simple new model of sequential search among finitely many options that fits many economic applications. Each payoff is the sum of a random “known factor” and a “hidden factor”, learned at cost. Weitzman (1979) solved the ex post Pandora's box problem, given known factors....

We explore costly sequential search among finitely many risky options, and an outside option. Payoffs are the sum of a known and hidden random factor.(a) We resolve a long open question about how riskier payoffs impact search duration: expected search time is higher for more dispersed...

We formalize a decentralized market where consumers with privately-known preferences meet bilaterally with firms. The latter acquire information to raise their degree of price discrimination from second to first. In a dynamic setting where outside options are endogenous, information choices are...

We analyze dynamic general equilibrium models with more-or-less directed search by informed buyers and random search by uninformed buyers. This nests existing specifications and generates new insights. A quantitative application concerns the welfare cost of inflation, which is known to be quite...

This note uses monotone methods to derive two sets of comparative statics results for monetary directed search models. First, it characterizes the impact of a higher inflation rate or a higher cost of using credit on market outcomes, regardless of the choice of matching function. Second, the...

This paper studies asset markets where buyers of assets do not inherit private information from previous owners and must learn asset quality over time. Imperfect information transmission reduces asymmetric information, but also reduces the trading volume, prices and efficiency. This result is...