One HIV infection could be prevented for every five to 15 men circumcised in settings with high levels of HIV and low rates of male circumcision — at a cost of US $150 to $900 per HIV infection averted over 10 years — concluded an expert review of six simulation models that estimated the impact of the scale-up of male circumcision on HIV. In this video Dr. Catherine Hankins of the Joint United Nations Programme on HIV/AIDS (UNAIDS) discusses the findings of the review, which was conducted by experts convened by UNAIDS, the World Health Organization, and the South African Centre for Epidemiological Modelling and published in PLoS Medicine. Dr. Hankins explains that these modelling results guided the development of the Male Circumcision Decision-makers’ Program Planning Tool.