Mechanisms for belief elicitation without ground truth

This review article examines the challenge of eliciting truthful information from multiple individuals when such information cannot be verified against an objective truth, 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. The analysis finds that although many mechanisms theoretically ensure truthfulness as a Bayesian Nash Equilibrium, empirical evidence of such mechanisms working in practice is very limited and generally weak. Consequently, more empirical research is needed to validate mechanisms. Given that many mechanisms are very complex and cannot be easily conveyed to research subjects, this review suggests that simpler, more intuitive mechanisms may be easier to test and apply.