The use of ex post Cost-Benefit Analysis to assess the long-term effects of Major Infrastructure Projects

This paper draws and expands from a recent ex-post evaluation carried out for the European Commission aimed at assessing the long term effects produced by a sample of ten major infrastructures in the Transport and Environment sectors and interpreting the key determinants of the observed performance. This evaluation study offered a unique opportunity to draw conclusions on the value of performing ex-post evaluations and to test an innovative evaluation design combining cost-benefit analysis (CBA) with qualitative assessment and adopting a long-run perspective (30 years), which extends into both the past and the future, and requires a mix of retrospective and prospective analysis. This paper presents the potential of ex-post CBA to assess long term impacts of major infrastructure projects and discusses some methodological and institutional implications related to its use.