Mechanisms for belief elicitation without ground truth

Abstract: This review article examines the challenge of eliciting truthful information from multiple individuals when such information cannot be verified, a problem known as information elicitation without verification (IEWV). This article reviews over 25 mechanisms designed to incentivize truth-telling in such scenarios and their effectiveness in empirical studies. Although many mechanisms theoretically ensure truthfulness as a Bayesian Nash Equilibrium, empirical evidence regarding the effects of mechanisms on truth-telling is limited and generally weak. Consequently, more empirical research is needed to validate mechanisms. However, empirical validaton is difficult because most mechanisms are very complex and cannot be easily conveyed to research subjects. This review suggests that simple and intuitive mechanisms may be easier to empirically test and apply.