Two case studies will be described.  DOTS has been widely used and promoted by the WHO to enhance adherence to TB medication yet evidence for its effectiveness remains equivocal. This case study will illustrate the challenges encountered when evidence contradicts standard practices.  For the second case study of male circumcision for preventing HIV/AIDS acquisition, we will reflect on some successful strategies for engaging with global policy-makers and the importance of looking beyond the evidence when diverse cultural and behavioural implications exist.