Public debt and welfare in a quantitative Schumpeterian growth model with incomplete markets

This paper quantifies the welfare effects of counterfactual public debt policies using an endogenous growth model with incomplete markets. The economy features public debt, Schumpeterian growth, infinitely-lived agents, uninsurable income risk, and discount factor heterogeneity. Two versions of the model are specified, one with households holding equity in the group of innovating firms. The model is calibrated to the U.S. economy to match the degree of wealth inequality, the share of R&D expenditure in GDP, the firms’ exit rate, the average growth rate, and other standard long-run targets. When comparing balanced growth paths, I find large welfare gains in equilibria characterized by governments accumulating public wealth. The result is robust to the mechanism used to generate a highly concentrated wealth (i.e., preference heterogeneity or “superstar” income shocks). Welfare effects decompositions show that level effects and growth effects reinforce each other. The responses of both the intermediate goods and their market conditions are key in explaining the large level effects. The version of the model without equity is computationally easier to solve, allowing to consider transitional dynamics. Taking into account the dynamic adjustment to the new long-run equilibrium, I show that the transitional welfare costs are not large enough to change the sign of the welfare effects stemming from a change in public debt. I find that eliminating public debt would lead to a 0.8% increase in welfare, while moving to a debt/GDP ratio of 100% would entail a welfare loss of 0.5%. A decomposition analysis shows that growth accounts for approximately 50% of the overall welfare effects.     

Model uncertainty,economic development,and welfare costs of business cycles

Some researchers argue that the welfare gains from eliminating consumption fluctuations for the United States are not small once model uncertainty is taken into account. This paper presents new evidence on the welfare gains from eliminating model uncertainty using a data set from a broad range of countries. It quantifies exactly the effect of model uncertainty on the welfare gains using an analytical formula. The results indicate that most countries derive much larger gains from the reduction of model uncertainty compared with the United States. Countries at higher stages of economic development tend to have lower welfare gains because their gains from eliminating model uncertainty become smaller. This relationship does not depend on country size or trade openness.