I Don't Know

Experts with reputational concerns, even good ones, are averse to admitting what they don’t know. This diminishes our trust in experts and, in turn, the role of science in society. We model the strategic communication of uncertainty, allowing for the salient reality that some questions are ill-posed or unanswerable. Combined with a new use of Markov sequential equilibrium, our model sheds new light on old results about the challenge of getting experts to admit uncertainty – even when it is possible to check predictive success. Moreover, we identify a novel solution: checking features of the problem itself that only good experts will infer – in particular, whether the problem is answerable – allows for equilibria where uninformed experts do say “I Don’t Know.”