Wrongful convictions and the Blackstone ratio: An empirical analysis of public attitudes

When deciding on the issue of guilt, a judge or jury can make two types of error: convicting an innocent person (false positive) or acquitting a guilty person (false negative). The Blackstone ratio addresses the relation between false positive and false negative verdicts. The ratio depends on how much certainty the judicial decision-maker requires before convicting an accused. This article describes an experimental study of Dutch community views about the Blackstone ratio. It was hypothesized that public views on this issue may depend on seriousness of the offence. Moreover, it is expected that providing balanced information on the consequences of both convicting an innocent and acquitting a guilty person would result in more deliberated and informed public judgement on the Blackstone ratio. We manipulated both the seriousness of the crime and information about the consequences of false positive and false negative verdicts. Findings reveal that public reactions to the criteria for deciding upon guilt or innocence are dynamic and vary with the seriousness of the crime. The provision of information relating to the two types of judicial error had no significant effect on public attitudes.