This book offers quantitative insights to lawyers and teaches them to work with numbers. The ability to deal with quantitative data is becoming increasingly important for lawyers. Estimates, probabilities and the likelihood that something will or will not happen in relation to a legally relevant insight or legal consideration, has become an important skill. We can witness its relevance in a famous case in The Netherlands – the case of Lucia de Berk, an unfortunate nurse who had been present at (initially) thirty deaths. According to the Public Prosecution Service, it was statistically practically impossible that this was a coincidence and although the medical evidence was weak, the statistical evidence lead to her conviction. Was this a miscarriage of justice or can we rely on the statistics? This book offers quantitative insights to lawyers and teaches them to work with numbers. What is the context of those numbers? How can you make, interpret and evaluate probability judgements and predictions? As a lawyer, you do not need to know the exact technical details, but you do need to be able to ask the right questions and interpret the experts’ answers. 1 Basic math; 2 Basic concepts in statistics; 3 Simple probability distribution; 4 Two approaches in statistics; 5 Simple regression model; 6 Multiple regression model; 7 Creating and evaluating forecasts; 8 Learning from forecast errors; 9 Algorithms; Answers to selected exercises; Examples of multiple-choice questions: test yourself