Consider a mechanism design setting in which agents acquire costly information about an unknown, payoff-relevant state of nature. Information gathering is covert. We investigate conditions under which (i) efficient implementation and (ii) full surplus extraction are Bayesian incentive compatible...

It is well known that when agents' types are correlated, the mechanism designer can extract the entire surplus. This creates an incentive for agents to acquire information about other agents' types. Robust lotteries (are payment schemes that) support full extraction and partially robust...