The use of performance enhancing drugs is the dark side of sport, and there are stringent measures in place to try to screen athletes. But what's the likelihood that an athlete who fails a drug test has actually taken the banned drug? What do you think is the fairest way to construct a drug-testing regime? This activity, aimed at A-level students (Key Stage 5), explores some of the mathematics involved, inviting students to work with conditional probabilities and introducing the payoff matrix, an important representation in Game Theory.

Detailed teachers' notes for this activity are available on our NRICH website.



Further information and related resources

Detailed teachers' notes for this activity are available on our NRICH website.

Our article The logic of drug testing by John Haigh and Mike Pearson examines conditional probability in sports doping tests, and includes an animated illustration.

Our article Blast it like Beckham by John Haigh also examines payoff matrices, looking at what Game Theory can tell us about how to take a penalty kick in football.