We investigate the evolution of common law under overruling, a system of precedent change in which appellate courts replace existing legal rules with new ones. We use a legal realist model, in which judges change the law to reflect their own preferences or attitudes, but changing the law is...

Does it matter for the outcome of a trial who the judge is? Legal practitioners typically believe that the answer is yes, yet legal scholarship sees trial judges as predictably enforcing established law. Following Frank (1951), we suggest here that trial judges exercise considerable discretion...