This paper develops a dynamic general equilibrium model of economic growth. The model has a steady state equilibrium in which some firms devote resources to discovering qualitatively improved products and other firms devote resources to copying these products. Rates of both innovation and imitation are endogenously determined based on the outcomes of R&D races between firms. Innovation subsidies are shown to unambiguously promote economic growth. Welfare is only enhanced however if the steady state intensity of innovative effort exceeds a critical level.

Technology change is modeled as the result of decisions of individuals and groups of individuals to adopt more advanced technologies. The structure is calibrated to the U.S. and postwar Japan growth experiences. Using this calibrated structure we explore how large the disparity in the effective tax rates on the returns to adopting technologies must be to account for the huge observed disparity in per capita income across countries. We find that this disparity is not implausibly large.

This paper proposes a model of diversifiable uncertainty, irreversible investment decisions, and endogenous growth. The detailed microeconomic structure of the model makes it possible to study the. general equilibrium effects of obstacles to labor mobility, due to institutional as well as technological features of the economy. Labor mobility costs reduce private returns to investment, and the resulting slower rate of endogenous growth unambiguously lowers a representative individual's welfare. Turnover costs can have positive effects on full employment equilibrium wages when all external effects are disregarded: this may help explain why policy and institutions often tend to decrease labor mobility in reality, rather than to enhance it. Lower flexibility, however, reduces the growth rate of wages in endogenous growth equilibrium, with negative welfare effects even for agents who own only labor.

In this paper we study the relationship between wealth, income distribution and growth in a game-theoretic context in which property rights are not completely enforcable. We consider equilibrium paths of accumulation which yield players utilities that are at least as high as those that they could obtain by appropriating higher consumption at the present and suffering retaliation later on. We focus on those subgame perfect equilibria which are constrained Pareto-efficient (second best). In this set of equilibria we study how the level of wealth affects growth. In particular we consider cases which produce classical traps (with standard concave technologies): growth may not be possible from low levels of wealth because of incentive constraints while policies (sometimes even first-best policies) that lead to growth are sustainable as equilibria from high levels of wealth. We also study cases which we classify as the "Mancur Olson" type: first best policies are used at low levels of wealth along these constrained Pareto efficient equilibria, but first best policies are not sustainable at higher levels of wealth where growth slows down. We also consider the unequal weighting of players to ace the subgame perfect equiliria on the constrained Pareto frontier. We explore the relation between sustainable growth rates and the level of inequality in the distribution of income.