The process was first carried out in 2004, and led to additional funding allocated to HIV/AIDS projects, “which topped the economists’ “to do” list”. Similarly, biosand filters was the intervention with the lowest risk of a BCR below 1. In the final overall ranking, WSS interventions came in about 15th to 20th position (over a total of 30 interventions), whereas health interventions to address malnutrition (such as micronutrient supplements or community-based nutrition promotion) came towards the top, largely due to their comparatively low costs and fast payback periods. It does so by comparing the effectiveness of various health interventions based on the estimated cost per DALY averted (see Box 5.4).