Math in Trials

In Great Britain, November 1999, the respected lawyer Sally Clark has been wrongly accused of and imprisoned for the murder of her children. Clark came under suspicion of murder after her two sons (*1996, *1997) died within a short period of time after their birth.
People’s intuitive feel for statistical reasoning is often biased and/or incorrect, which can have large detrimental consequences. During this activity the courtcase of Sally Clark is used to raise students.

Lesson activities:
Introduction: Texts or videos about the case of Sally Clark. Activities for students:

• Try to understand the statistical reasoning behind both the conviction and the (three year later) acquittal of Sally Clark.
• Explore the difference between dependent and independent events with dice and a marble-draw. What are the similarities with the case of Sally Clark?
• Organize a (large) lottery in which there is one winner. Discuss with the group why the winning feels like luck instead of coincidence. Draw similarities with the case of Sally Clark.
• Debate with the class whether mathematics should really play an important role in the mediation and evidence of a crime, because of the risk of misinterpretation.
• Role-play court case: With your fellows take on the role of offense and defence in the case of Sally Clark. Make sure you statistically ground your arguments.