The productive contribution of infrastructure: positive and normative analyses.

Summary The thesis proposes both a positive and normative analysis of the productive contribution of infrastructure. The first chapter is devoted to the definition of infrastructure. This study shows that the notions of public capital and infrastructure capital are often confused and that most OECD countries have experienced a sharp decline in their infrastructure investments since the mid-1970s. The second chapter provides a synthesis of the literature on the evaluation of returns to public capital. This summary highlights the sensitivity of the econometric results to the specification of the models and to the inclusion of stochastic non-stationarity. The third chapter is devoted to an evaluation of the production function approach, carried out conditionally on a stochastic dynamic general equilibrium model. This chapter specifies the nature of the biases in the estimation of the contribution of public capital when it is understood through a production function. The fourth chapter evaluates the stabilizing properties of public investment. In an endogenous growth model, different public decision rules are evaluated. The spectral analysis of the shock response functions indicates that the more productive the expenditures are, the better their stabilizing properties. The fifth chapter identifies a set of rules for setting the optimal public investment rate. This study shows that the influence of the tax structure. It also shows how the level of infrastructure congestion affects the optimal rate of investment. The sixth chapter proposes a study of the discount rate of public projects in a growth model with tax distortions. The analysis shows that the discount rate is highly dependent on the nature of growth. The link between the discount rate and tax distortions is then examined.