Technological advance is often embodied in capital inputs. This paper develops a model where capital innovations occur on two margins: (1) vertically, where a capital input becomes more productive at a given task; and (2) horizontally, where a capital input replaces labor at a given task. These...

A unified growth theory is developed that accounts for the roughly constant living standards displayed by world economies prior to 1800 as well as the growing living standards exhibited by modern industrial economies. Our theory also explains the industrial revolution, which is the transition...

This paper develops a unified model of growth, population, and technological progress that is consistent with long-term historical evidence. The economy endogenously evolves through three phases. In the Malthusian regime, population growth is positively related to the level of income per capita....

Population growth has declined markedly in almost all major economies since the 1970s. We argue this trend has important consequences for the process of firm dynamics and aggregate growth. We study a rich semi-endogenous growth model of firm dynamics, and show analytically that a decline in...

Debt neutrality is said to occur if, given a program for public spending on current goods and services over time, the real equilibrium of the economy (private consumption, investment, relative prices, etc.) is independent of the pattern of government borrowing and lump-sum taxation over time....

For generations of scholars and observers, the "transportation revolution," especially the railroad, has loomed large as a dominant factor in the settlement and development of the United States in the nineteenth century. There has, however, been considerable debate as to whether transportation...

We develop a novel method for assessing the effect of constraints imposed by spatially-fixed natural resources on aggregate economic output. We apply it to estimate and compare the projected effects of climate change and population growth over the course of the 21st century, by country and...

We construct a model that combines elements of endogenous growth with the convergence implications of the neoclassical growth model. In the long run, the world growth rate is driven by discoveries in the technologically leading economies. Followers converge toward the leaders because copying is...

This paper discusses recent theoretical and empirical work on the interactions between growth and business cycles. One may distinguish two very different types of approaches to the problem of the influence of macroeconomic fluctuations on long-run growth. In the first type of approach, which...

The object of this paper is to show how population growth, through its interaction with recent technological and organizational developments, can account for many of the cross-country differences in economic outcome observed among industrialized countries over the last 20 years. In particular,...