Date:
Location:
The Growth Lab's Research Seminar series is a weekly seminar that brings together researchers from across the academic spectrum who share an interest in growth and development.
Speaker: Timo Välilä, Honorary Professor, The Bartlett School of Sustainable Construction, UCL
Location: HYBRID: WEXNER W-434 A.B. / Zoom
Whether attending in person or virtually, please register in advance.
Abstract.
This article undertakes a comparison of quantitative meta-studies at project level and at aggregate level to assess how well the economic impact of transport infrastructure is understood. Project-level analyses, based on the so-called Flyvbjerg database, have documented systematic cost overruns and, less conclusively, traffic demand shortfalls, and they have interpreted these findings as being indicative of negative social welfare consequences of transport infrastructure investment projects. In contrast, aggregate-level meta-analyses find consistently that there is a positive relationship between transport infrastructure and measured economic activity at the level of regions or countries, especially in the long run and at higher levels of geographical aggregation. This seeming tension between the meta-results at different levels has been considered a paradox. However, neither the project-level meta-results, nor the available ex post evaluations of larger samples of transport infrastructure projects provide any conclusive evidence of their social welfare consequences, and even if they did, changes in social welfare and economic activity do not need to point in the same direction. There is therefore no paradox about the economic impact of transport infrastructure – we just do not understand its social welfare consequences at the meta-level as well as we understand its relationship with measured aggregate output.