Estimating health impacts of interventions with a focus on small scale drinking water interventions

Having established a framework for identifying and costing interventions, we now move to the benefits side of economic assessment. In this chapter the focus will be on estimating the health impacts of small scale interventions giving improved access to safe drinking-water for a target group of people. The method could also be applied to other environmental health interventions such as new sanitation facilities or the introduction of educational or behavioural change programmes. Interventions can be conducted at the individual, household or community levels. They can include, for example, educating children about the importance of handwashing, digging pit latrines in people's homes or building small-scale water treatment plants collectively. Most of the discussion will be around how to estimate the likely change in disease prevalence and incidence that would follow a particular intervention. However, any environmental intervention is likely to have broader impacts than just those that impact on