In models in which convergence in income levels across closed countries is driven by faster accumulation of a productive factor in the poorer countries, opening these countries to trade can stop convergence and even cause divergence. We make this point using a dynamic Heckscher-Ohlin model — a combination of a static two-good, two-factor Heckscher-Ohlin trade model and a two-sector growth model — with infinitely lived consumers where international borrowing and lending are not permitted. We obtain two main results: First, countries that differ only in their initial endowments of capital per worker may converge or diverge in income levels over time, depending on the elasticity of substitution between traded goods. Divergence can occur for parameter values that would imply convergence in a world of closed economies and vice versa. Second, factor price equalization in a given period does not imply factor price equalization in future periods.

We examine the quantitative impact of policy-induced changes in innovative investment by firms on growth in aggregate productivity and output in a model that nests several of the canonical models in the literature. We isolate two statistics, the impact elasticity of aggregate productivity growth with respect to an increase in aggregate innovative investment and the degree of intertemporal knowledge spillovers in research, that play a key role in shaping the model’s predicted dynamic response of aggregate productivity, output, and welfare to a policy-induced change in the innovation intensity of the economy. Given estimates of these statistics, we find that there is only modest scope for increasing aggregate productivity and output over a 20-year horizon with uniform subsidies to firms’ investments in innovation of a reasonable magnitude, but the welfare gains from such a subsidy may be substantial.

Innovative activities have public good characteristics in the sense that the cost of producing the innovation is high compared to the cost of producing subsequent units. Moreover, knowledge of how to produce subsequent units is widely known once the innovation has occurred and is, therefore, non-rivalrous. The main question of this paper is whether mechanisms can be found which exploit market information to provide appropriate incentives for innovation. The ability of the mechanism designer to exploit such information depends crucially on the ability of the innovator to manipulate market signals. We show that if the innovator cannot manipulate market signals, then the efficient levels of innovation can be implemented without deadweight losses–for example, by using appropriately designed prizes. If the innovator can use bribes, buybacks, or other ways of manipulating market signals, patents are necessary.

In 1950 Mexico entered an economic takeoff and grew rapidly for more than 30 years. Growth stopped during the crises of 1982–1995, despite major reforms, including liberalization of foreign trade and investment. Since then growth has been modest. We analyze the economic history of Mexico 1877–2010. We conclude that the growth 1950–1981 was driven by urbanization, industrialization, and education and that Mexico would have grown even more rapidly if trade and investment had been liberalized sooner. If Mexico is to resume rapid growth — so that it can approach U.S. levels of income — it needs further reforms.

I develop an idea flows theory of firm and worker dynamics in order to assess the consequences of population aging. Older people are less likely to attempt entrepreneurship and switch employers because they have found better jobs. Consequently, aging reduces entry and worker mobility through a composition effect. In equilibrium, the lower entry rate implies fewer new, better job opportunities for workers, while the better matched labor market dissuades job creation and entry. Aging accounts for a large share of substantial declines in firm and worker dynamics since the 1980s, primarily due to equilibrium forces. Cross-state evidence supports these predictions.