Methodologies to assess the impact of infrastructure projects in international development evaluation

Ex-post evaluation of infrastructure projects is attempted by international and national organisations in different ways. Qualitative case studies, relying on documentary analysis, interviews and surveys, are regularly carried out, for example, by the European Commission, the World Bank, the European Investment Bank and Regional Development Banks. The aim of case studies is to provide an in-depth understanding of the project context and performance. The World Bank has also put in place a rating system to assess the performance of all investment operations financed, allowing for immediate comparability of results across sectors, countries, macro-regions, programmes and lending instruments. Some institutions and countries (e.g. the European Commission, the World Bank and the United Kingdom) make use of quantitative methods to measure infrastructure projects effects, like ex-post CBA. This method is mostly used to re-assess ex-ante appraisal results with more up-to-date data. An innovative way of integrating ex-post CBA and qualitative evidence is offered by the recent Commission’s evaluation of major projects financed in the 1994-1999 period. Such research project allowed to study in a structured way not only project effects, but also determinant mechanisms of success or failure, leading to meaningful and generalised lessons about infrastructure project performance. The evaluation design and specificities characterising this approach are described and the main advantages highlighted.