An uninformed sender publicly commits to an informative experiment about an uncertain state, privately observes its outcome, and sends a cheap-talk message to a receiver. We provide an algorithm valid for arbitrary state-dependent preferences that will determine the sender's optimal experiment,...

A sender who wants to influence a decision maker has no incentive to collect information if he has to reveal all evidence so obtained, because the expected value of posterior belief is equal to the prior. If he can conceal his evidence at a cost, he invests more in obtaining information when...