Le multiplicateur d'investissement public

This article gives a summary of the results of the main studies of the impact assessment of public expenditure and in particular of public investment. This assessment is carried out in three successive points: (1) Since public investment is primarily a component of demand, we have f irst looked at its eff ectiveness in terms of general public spending. T he literature leads to a multiplier of public spending on GDP of 0.8 on average, with great variability in the results. (2) Secondly, the productive dimension of public investment is integrated. The economic literature manages to establish a superiority in the long run of the revival by investment in relation to classical expenditure. The contribution of public capital to growth, measured by elasticity, varies between 0.01 and 0.5. These elasticities are high if project selection is eff ective and public capital is properly used. On the other hand, the literature tends to underline the superiority in terms of short-term revival of public consumption over new public infrastructure projects whose implementation times would be ver y long. (3) Finally, the current debate on spending stimulus is in the middle of an economic crisis, the article shows that in the literature the multiplier increases in times of crisis to high values between 1.3 and 2.5. In addition, the result observed in normal times is reversed: the recovery by major public investment projects is stronger than by public consumption.