Exploring the reasons for efficiency in Spanish airports

In recent years the Spanish government has invested significantly in the infrastructure of airports. It is not clear if this investment has been efficiently applied. Airports operate as independent profit centres but are under the control of a central authority, AENA. We study Spanish airport efficiency using Data Envelopment Analysis (DEA). In standard studies, DEA summarises the efficiency of a unit by means of a single number. Here we go beyond the efficiency score by combining DEA with multivariate analysis techniques. In this way we are able to establish why a particular airport reaches a given efficiency level, and what is its approach to the use of resources and the achievement of results. The combined use of DEA and multivariate statistical analysis overcomes the well-known zero weights problem and permits the visualisation of the results and the addition of qualitative information to the interpretation of the results. On this basis, for each unit of assessment (airport), individual managerial recommendations are drawn. Additionally, the visualisation allows differentiating between units more efficient in certain operations compared to others (specialisation).