Economic Growth Before 1860: Revised Conjectures

The current view of U.S. economic growth before 1860 is based on the conjectural estimates of output made by Paul David (1967). This paper sets forth new estimates of the farm labor force for the period 1800 to 1860 and uses them to revise those conjectures about growth of per capita output. An additional conjectural estimate is produced based on recent evidence about manufacturing productivity. The new estimates lower the farm labor forces in the years before 1830 by 10 to 15 percent, while raising the figures for 1840, 1850, and 1860 by 5 to 9 percent. As a consequence the farm work force grew more rapidly than was previously believed, and farm productivity grew more slowly. The impact of the revisions varied by subperiod, and is concentrated almost entirely in the middle 20 years. Because the advance in farm productivity was the major determinant of change in the conjectural estimates of per capita output, that series shows a slower rate of growth as well, especially over the period 1820 to 1840. A refined estimate, which incorporates the recent evidence on manufacturing productivity, alters the picture somewhat, but still shows slower growth and more gradual acceleration of output per capita than is revealed in the David series.

The Farm Labor Force by Region, 1820-1860: Revised Estimates and Implications for Growth

This paper sets forth new estimates of the farm labor force covering the period 1820 to 1860, for the United States and the major geographic regions. At the national level, the new figures are noticeably different from the previous estimates. In particular, the new estimates lower the 1820 farm labor force by about 8 percent, while raising the figures for 1840, 1850, and 1860 by 7 to 10 percent. As a consequence, the farm work force grew more rapidly than was previously believed, while farm productivity and per capita income grew more slowly. The impact of the revisions, of course, varied by subperiod. The new figures also alter our picture of variations in regional economic performance, the more so in some regions. In particular, the pace and timing of the shift out of farming in New England has been changed substantially. The paper also discusses the reasons for the discrepancies between the new and old series, and provides some assessment of the new evidence.

Reflected Brownian motions in the KPZ universality class

This book presents a detailed study of a system of interacting Brownian motions in one dimension. The interaction is point-like such that the $n$-th Brownian motion is reflected from the Brownian motion with label $n-1$. This model belongs to the Kardar-Parisi-Zhang (KPZ) universality class. In fact, because of the singular interaction, many universal properties can be established with rigor. They depend on the choice of initial conditions. Discussion addresses packed and periodic initial conditions, stationary initial conditions, and mixtures thereof. The suitably scaled spatial process will be proven to converge to an Airy process in the long time limit. A chapter on determinantal random fields and another one on Airy processes are added to have the notes self-contained. This book serves as an introduction to the KPZ universality class, illustrating the main concepts by means of a single model only. It will be of interest to readers from interacting diffusion processes and non-equilibrium statistical mechanics.Comment: arXiv admin note: text overlap with arXiv:1502.0146

Diffusion coefficients for multi-step persistent random walks on lattices

We calculate the diffusion coefficients of persistent random walks on lattices, where the direction of a walker at a given step depends on the memory of a certain number of previous steps. In particular, we describe a simple method which enables us to obtain explicit expressions for the diffusion coefficients of walks with two-step memory on different classes of one-, two- and higher-dimensional lattices.Comment: 27 pages, 2 figure

A Conceptual Framework for Studying the Sources of Variation in Program Effects

Evaluations of public programs in many fields reveal that (1) different types of programs (or different versions of the same program) vary in their effectiveness, (2) a program that is effective for one group of people might not be effective for other groups of people, and (3) a program that is effective in one set of circumstances may not be effective in other circumstances. This paper presents a conceptual framework for research on such variation in program effects and the sources of this variation. The framework is intended to help researchers -- both those who focus mainly on studying program implementation and those who focus mainly on estimating program effects -- see how their respective pieces fit together in a way that helps to identify factors that explain variation in program effects and thereby support more systematic data collection on these factors. The ultimate goal of the framework is to enable researchers to offer better guidance to policymakers and program operators on the conditions and practices that are associated with larger and more positive effects