A multi-period, multi-criteria model for dynamic performance assessment of the Portuguese water sector

We develop and apply a multi-period overall performance evaluation model, supported by multi-criteria decision aid methods, to assess the dynamic performance of Portuguese water service providers. Data from 2018 to 2021 provided by the regulation authority were used, and a preference elicitation procedure was applied to a pool of experts to determine the scale coefficients associated with the importance of the criteria and with each period under analysis. The results reveal peculiarities that would not be visible using a single-period evaluation process or a criterion-by-criterion evaluation model. For example, we identify service providers with unsatisfactory performance in areas critical to achieving the sector's strategic goals. We highlight the trend of stagnating performance in most indicators, even those that have shown unsatisfactory performance over the years, as is the case with the non-revenue water and major rehabilitation indicators. After applying the model, we can conclude that none of the water utilities is rated as providing “good quality service".