Does introducing lay people in criminal courts affect judicial decisions?

Abstract

What is the effect of introducing jury members in criminal courts? While surveys regularly point out a demand by citizens for harsher punishment, the differences between surveys’ and real decisions’ conditions are large enough to cast a doubt on the results. The introduction of two jurors into a court composed of three professional judges in two French regions and for a subsample of crimes during sixteen months offers a good natural experiment. Difference-in-differences or triple-difference methods do not permit me to identify any major change in the probability of being convicted or in sentences given by a court including jurors. If some characteristics of the reform could partly explain those null results, they clearly go against the hypothesis of a major disagreement between professional judges and citizens when they have to make real decisions in criminal cases.