We systematically study cornerstones that must be solved to define an air
traffic control benchmarking system based on a Data Envelopment Analysis.
Primarily, we examine the appropriate decision-making units, what to consider
and what to avoid when choosing inputs and outputs in the case that several
countries are included, and how we can identify and deal with outliers, like
the Maastricht Service Provider. We argue that Air Navigation Service Providers
would be a good choice of decision units within the European context. Based on
that, we discuss candidates for DEA inputs and outputs and emphasize that
monetary values should be excluded. We, further suggest to use super-efficiency
DEA for eliminating outliers. In this context, we compare different DEA
approaches and find that standard DEA is performing well.Comment: 14 Pages, to be published in JAT