Economic Inefficiency Levels of Urban Solid Waste Management Services in Portugal

Key performance indicators (KPI) are widely used tools to evaluate the economic (in)efficiency of services, including the ones devoted to urban solid waste management. Regulatory exercises are, then, mostly based on the outputs from KPIs, raising some questions about their validity. In theory, other more appropriate tools could be used to estimate those efficiency levels. This study evaluates the economic inefficiency level of urban solid waste management services in Portugal (2010–2017) through the adoption of partial frontier benchmarking models (order-m) coupled with weight restrictions. That way, the constructed model can evaluate the performance of those services under some regulatory and sustainability requirements. Then, estimated efficiency levels and some common KPIs are compared in order to understand if the latter are sufficient to explain the economic efficiency. The novelty of this research lies in two main aspects: (a) the utilization of a robust order-α model coupled with weight restrictions linked to regulatory and sustainability impositions to estimate efficiency, and (b) the comparison of economic efficiency and some commonly used KPIs, including waste fractions and recycling rate. Results point towards efficiency distributions that follow Weibull functions, with the average close to 50%; thus, nearly half of the resources have been well spent in municipal solid waste management services since 2010 onwards. Nonetheless, in an efficient system, that average would be close to 100%. Additionally, the considered management related KPIs do not exhibit any relationship with economic efficiency, which means that their interpretation and usefulness for regulatory issues are both limited and should be used carefully. In other words, those KPIs are not good performance drivers and carry no capacity to explain economic (in)efficiency in urban solid waste management services.