Obvious belief elicitation

Abstract

An investigator is interested in arbitrarily approximating a subject's latent beliefs in obviously dominant strategies (Li, 2017). We prove that Karni's ascending mechanism (Karni, 2009) does not have an obviously dominant strategy. Thus, we introduce the novel descending Karni mechanism which always has obviously dominant strategies. Furthermore, under the assumption that the subject chooses an obviously dominant strategy, the true beliefs can be approximated with arbitrary precision with our mechanism. All our results hold for a very broad class of likelihood relations, going well beyond those that are represented by probabilistic beliefs.