This paper aims to focus on assessing the effect which factors that cannot be controlled by the public administrator on the efficiency of municipalities on rendering sewerage services.
The analyses performed to date focus mainly on technical efficiency due to the low importance of public outputs value. For it, a four‐stage process was followed in order to observe the overall effect produced by operation size and environmental conditions on efficiency index estimated by data envelopment analysis.
The results obtained show that operation size and environmental conditions have a significant impact on efficiency indices and on reducing the variability between indices; however, the type of management proprietorship, public vs private, does not impact the degree of efficiency.
As regards decisions stemming from intermunicipal comparison, it can be seen that a drastic decrease occurs in input reduction and output increase percentages geared towards making the municipality under observation efficient in relation to those initially detected, without taking into consideration factors which cannot be controlled by the administrator.
This paper is pioneering in knowing the intensity of the effect of certain factors on the benchmarking process.
