Universidad Autónoma de Madrid. Department of Economic Structure and Development Economics, C/ Francisco Tomás y Valiente, 5, PC: 28049, Madrid, Spain.
J Environ Manage. 2020 May 1;261:109921. doi: 10.1016/j.jenvman.2019.109921. Epub 2020 Mar 2.
Most estimations of residential water demand are based on single-equation models that rely on assumptions that are most often not compatible with the fundamental principles of consumer theory. In this paper, we relax these assumptions by using a more flexible system of demand estimation, the Quadratic Almost Ideal Demand System (QUAIDS) (Banks et al., 1997) and reveal the existence in our sample of substitution and complementary patterns as well as non-linearities in Engel curves for water consumption. Water demand would not be, therefore, linear in income and separable from other goods consumed within the household. In this context the QUAIDS functional specification is expected to be more consistent with observed consumer behavior. Our results seem to confirm this expectation; when compared to the linear, log-linear and double-log models commonly used in water demand estimation, QUAIDS seems to produce a better overall fit and a better fit to the asymmetric shape of the real distribution of water consumption. This has important implications in terms of public policy, as it allows to explore how water policies interact with other goods consumed within the household (e.g. water-energy nexus or efficient household appliances). Furthermore, differential responses to pricing policies and taxes across the income distribution can be considered, thus contributing to avoid undesired redistributive effects and water poverty.
大多数住宅水需求估计都是基于单方程模型，这些模型依赖于最常见的与消费者理论基本原则不兼容的假设。在本文中，我们通过使用更灵活的需求估计系统——二次近似理想需求系统（QUAIDS）（Banks 等人，1997 年）来放松这些假设，并揭示了我们的样本中存在替代和互补模式以及水消费恩格尔曲线的非线性。因此，水需求不会与收入呈线性关系，也不会与家庭内消费的其他商品分离。在这种情况下，QUAIDS 功能规范预计将与观察到的消费者行为更一致。我们的结果似乎证实了这一预期；与在水需求估计中常用的线性、对数线性和双对数模型相比，QUAIDS 似乎产生了更好的整体拟合度，并且更符合实际水消费分布的不对称形状。这在公共政策方面具有重要意义，因为它允许探索水政策如何与家庭内消费的其他商品相互作用（例如，水-能源关系或高效家用电器）。此外，可以考虑对不同收入分布的定价政策和税收的差异反应，从而有助于避免不必要的再分配效应和水贫困。
