240   The Global HIV Epidemics among Sex Workers
they work, and the principles of a community-empowerment based intervention as defined in this report. To generate cost estimates for Kenya, Thailand, and Ukraine we used the base case cost analysis from the Brazilian micro-costing exercise to establish model program implementation parameters, and adapted the values to each country. To do this we first adjusted the Brazilian values to current 2011 U.S. Dollars, and weighted the results by the Purchasing Power Parity (PPP) index (UN Statistics Division Millennium Development Indicators Unit 2012) for each country. The resulting values were then reviewed and adjusted as needed by comparison results to available labor statistics (International Labor Organization 2012), comparisons to other available micro-costing results conducted previously by the study team, and expert consultation with colleagues who have implemented field projects in these settings. Once reasonable estimated base-case scenarios were established for each country we then incorporated other required adjustments to the cost data, including discounting, annuitization and distribution of startup costs over the life of project, and calculation of net program costs for a separate analysis which subtracts the estimated lifetime treatment costs from total program costs. We also developed a model to convert HIV infections averted (from the Goals model) to Disability Adjusted Life Years (DALY) saved, and conducted sensitivity analyses on the cost data from Brazil with a stochastic model. These are described below. Time Preference An important consideration in any cost-effectiveness analysis is the value given to present versus distant benefits of the interventions being considered. Even with zero inflation there is a societal preference for intervention benefits incurred sooner over those realized later in time. To account for this it is necessary to discount the future costs and benefits of the interventions under consideration. Following recommendations set by the U.S. Panel on Cost-Effectiveness in Health and Medicine (Gold 1996) we harmonized the discount rate used for costs with those used for benefits, and utilize a 3% discount rate, with sensitivity analysis conducted with a 0%, 3%, and 6% discount rate. We also utilized these same discount rates in the annuity function for one-time capital expenditures, and to discount the future health benefits. Startup costs were distributed over the life of the intervention (3 years) using an annuity function with results discounted at 0%, 3% and 6%. For calculation of Disability Adjusted Life Years saved per HIV infection averted, and lifetime ART treatment costs we utilized a 3% discount rate.