Truth-Bonding and other Truth-Revealing Mechanisms for Courts

Robert Cooter, UCB
Winand Emons, University of Bern, Switzerland

Abstract

In trials witnesses often gain by slanting their testimony. The law tries to elicit the truth from witnesses by cross-examination under threat of criminal prosecution for perjury. As a truth-revealing mechanism, perjury law is crude and ineffective. We develop the mathematical form of a perfect truth-revealing mechanism, which exactly offsets the gain from slanted testimony by the risk of a possible sanction. Implementing an effective truth-revealing mechanism requires a witness to certify accuracy by posting bond. If events subsequently prove that the testimony was inaccurate, the witness forfeits the bond. By providing superior incentives for telling the truth, truth-bonding could combat some distortions by factual witnesses and interested experts, including “junk science”.