Demand expression varies by the kind of goods or services being delivered. Water supply and latrines are an example of essentially private goods, goods that are individually used and for which indi- vidual users can express and realize a willingness to pay. Public choices are more complicated with respect to public goods such as schools or rural roads; a differentiated strategy for eliciting demand, depending on the kind of subproject that is being produced, is needed. The second determinant of sustainability is the appropriateness of the technical choices presented to communities in light of their effec- tive demand for levels of service that the technology provides. Tech- nology choices must.
