Participation is open to all and particularly welcome from anyone attending the one-day R for cost-effectiveness analysis and modelling workshop in London on 9th July (details of the workshop here). http://www.statistica.it/gianluca/teaching/r-hta-workshop/2019/ Participants should email their code solutions, including a main.R or main.Rmd script, to [log in para visualizar] by 24th June 2019. Code will be judged on the grounds of speed, elegance, and transparency/readability. First, second, and third place ranked solutions will be given signed e-certificates confirming their achievement. However, this exercise aims to encourage a collaborative approach to the programming and there will be time for discussion of solutions and problems at the 9th July workshop. Participants will be encouraged to briefly talk through their solutions.