Ofwat publishes the indicators annually in a public report. These simple performance scorecards have helped measure the efficiency of service provision and pressure the “worst in the class” (Kingdom and Jagannathan, 2001). Such tools need to be used with caution, however, as differences in performance can be due to a variety of factors aside from relative efficiency, such as differences in physical conditions, population density, nature of the terrain, age of the network, etc. For this reason, Ofwat has developed sophisticated econometric models to assess comparative efficiency of regulated companies while controlling for exogenous factors that can affect performance. In OECD countries, the regulatory regime in place can influence the selection of investment options, linked to the set of incentives that they introduce.