Despite a broad consensus that infrastructure is essential for economic development, invest- ment in infrastructure is far below what is needed, even in developed countries. One of the main reasons is that it is difficult to assess with certainty the medium- and long-term bud- getary impacts (expenditure and revenue) generated by a project, as this assessment calls for a micro-economic analysis of the project (cost-benefit analysis) to be linked with budgetary macroeconomic impacts, through country-specific financial mechanisms. In general, the cost benefit analysis stops just before the budget impact assessment. As a result, evaluations predict an almost systematic deterioration in the debt-to-GDP ratio and thus slow down the invest- ment decision. However, some projects generate future direct and indirect revenue streams for the State, the discounted value of which is higher than the initial investment. In this paper, we propose a new evaluation method, the Global Project Assessment Method (GLOPRAM), which takes into account the complexe nature of investment assessment for public decision and better reflects the economic and budgetary reality. More specifically, the GLOPRAM makes it possible, for a given project, to reconcile the socio-economic assessment, the environmental impact study and the budgetary impact.

Jeanne Amar & Vincent Piron

December 2020