Only a few studies have estimated the overall benefits from WSS investments at the level of a given country on the economy as a whole (using economic indicators such as percentage of GDP). Taking a comprehensive view of benefits is important as certain economic sectors can benefit from combined actions at different steps of the WSS value chain. For example, the agricultural or the tourism sectors can benefit from investment in both up-stream and down-stream activities of the value chain. In a first phase, the ESI carried out comprehensive assessment of the impact of poor sanitation on the economies of five South East Asian countries (see Box 5.1).