The use and misuse of statistical evidence in criminal proceedings

Abstract

This article explains how statistical analysis of evidence can be used by lawyers for interpreting data in criminal justice proceedings. It elucidates basic statistical terms which need to be understood by both prosecutors and defence lawyers in presenting their cases to the court. It also shows that such knowledge is essential in cross-examining an expert in court and how statistical argument should be used correctly to avoid arriving at fallacious deductions. It is impossible in a single article to fully explain the knowledge and technical skills required to become an expert in statistics, however, the legal professional needs to be able to interpret and evaluate statistical concepts and results which are commonly used in criminal law. The use of statistical evidence in the legal system is ever increasing and obligates lawyers as well as expert witnesses to obtain a strong background in the physical sciences including a basic understanding of statistics in order better to make expert testimony intelligible to the decision-maker.