Judges in the Lab: No Precedent Effects, No Common/Civil Law Differences
Harvard Law School John M. Olin Center Discussion Paper No. 1044 (2020)
127 Pages Posted: 5 Dec 2020 Last revised: 29 Jul 2021
Date Written: October 11, 2020
In our lab, 299 real judges from seven major jurisdictions (Argentina, Brazil, China, France, Germany, India, USA) spend up to 55 minutes to judge an international criminal appeals case and determine the appropriate prison sentence. The lab computer (1) logs their use of the documents (briefs, statement of facts, trial judgment, statute, precedent), and (2) randomly assigns each judge (i) a horizontal precedent disfavoring, favoring, or strongly favoring defendant, (ii) a sympathetic or an unsympathetic defendant, and (iii) a short, medium, or long sentence anchor. Document use and written reasons differ between countries but not between common and civil law. Precedent effect is barely detectable and estimated to be less, and bounded to be not much greater, than that of legally irrelevant defendant attributes and sentence anchors.
Keywords: Common/civil law, judicial decision-making, experiment, comparative law, bias, anchoring, precedent, methodology
JEL Classification: K14, K15, K40
Suggested Citation: Suggested Citation