Health, safe water and sanitation: a cross-sectional health production function for central Java, Indonesia.

The study describes the development of health production functions and their application in the evaluation of the health impacts of investments in safe water and sanitation. For this purpose, data on the morbidity of waterborne diseases and diarrhoea were collected from medical records in the province of Central Java, Indonesia. A reciprocal production function was found to fit the data best. The health production functions exhibit constant return to scale, i.e., a simultaneous m-fold increase in both safe water and sanitation coverage produces a 1-1/m decrease in morbidity. Safe water was found to be more important for health than the sanitary disposal of excreta.