Cost efficiency in municipal solid waste service delivery. Alternative management forms in relation to local population size

•Metafrontier approach to compare the cost efficiency of service delivery forms.•Application of order-m frontiers.•Cost efficiency of delivery forms depends on the size of municipalities.•Contracting out is more suitable in municipalities of over 20,000 inhabitants.

Considerable research has been devoted to the analysis of efficiency and of management forms for municipal waste collection, but widely varying results have been reported. In this paper, the metafrontier approach, by means of order-m frontiers, is used to analyse the efficiency of different ways of managing waste collection services, in order to determine which form is more appropriate. We compare the results obtained with this approach against those of previous theories. The advantage of applying this methodology is that unlike traditional nonparametric frontier analysis, we can compare the efficiency of different groups of municipalities according to their population size and to the management form adopted to supply the service. The results obtained suggest that, in general, cooperation formulas are the most suitable for the waste collection service. Thus, intermunicipal cooperation performs best in smaller municipalities (up to 20,000 inhabitants). However, we find that contracting out the service is associated with higher levels of efficiency in municipalities with more than 20,000 inhabitants.