IMPACT OF PRICING STRUCTURE SELECTIVITY ON URBAN WATER DEMAND

Interest in demand management policies has intensified as residential water demand has grown in the United States. Using data from the 1984 American Water Works Association (AWWA) survey, the study here provides an empirical analysis of the differences in price elasticities of demand across water pricing block structures and examines these structures' ''conservation-orientedness.'' However, a potential sample selection bias exists. That is, in cities where people are more interested in conservation, utility managers may be more likely to select a rate structure that they believe is conservation-oriented-an increasing block structure, for example. Managers' selectivity bias may cause research results either to understate or to overstate a particular block structure's impact on water conservation. The analysis here corrects for this selectivity bias in estimating water demand and tests whether consumers respond to average prices or to marginal prices. Correcting for selectivity bias involves an explicit analysis of the factors that influence utility managers' selection of rate structures. Estimating water demand under increasing and decreasing block structures suggests that sample selection bias remains a problem worthy of further investigation.