A Global Model for Forecasting Political Instability

Examining onsets of political instability in countries worldwide from 1955 to 2003, we develop a model that distinguishes countries that experienced instability from those that remained stable with a two-year lead time and over 80% accuracy. Intriguingly, the model uses few variables and a simple specification. The model is accurate in forecasting the onsets of both violent civil wars and nonviolent democratic reversals, suggesting common factors in both types of change. Whereas regime type is typically measured using linear or binary indicators of democracy/autocracy derived from the 21-point Polity scale, the model uses a nonlinear five-category measure of regime type based on the Polity components. This new measure of regime type emerges as the most powerful predictor of instability onsets, leading us to conclude that political institutions, properly specified, and not economic conditions, demography, or geography, are the most important predictors of the onset of political instability.     

The Use of Race and Ethnicity in Medicine: Lessons from the African-American Heart Failure Trial

Race or ethnic identity, despite its imprecise categorization, is a useful means of identifying population differences in mechanisms of disease and treatment effects. Therefore, race and other arbitrary demographic and physiological variables have appropriately served as a helpful guide to clinical management and to clinical trial participation. The African-American Heart Failure Trial was carried out in African-Americans with heart failure because prior data had demonstrated a uniquely favorable effect in this subpopulation of the drug combination in BiDil. The remarkable effect of the drug in reducing mortality in this study has illuminated an important new mechanism of therapy for heart failure. Application of these findings need not be confined to the population studied, but the observation highlights the need for more precise ways to identify individual responsiveness to therapy.     

Strength and growth in a plantation economy

Conclusion Fogel and Engerman's self-conscious application of economic theory to historical data is extremely useful in clarifying the market relationships operative in the antebellum Southern economy. What is missing in their study is an appreciation of the explanatory limits of the theory they have employed. They have paid a high price in attempting to stretch the capabilities of neoclassical theory into domains beyond its scope. In particular this takes the form of an implicit assumption that if market efficiency is attained, modernization is within reach. There is, on the contrary, no necessary correlation between efficiency defined in this market sense, and long-term strength, growth, or prosperity. Precisely because of the means employed within the plantation economy to achieve viability, there are serious questions which can be raised with respect to both the longevity of the slave system and the consistency of that system with development, and hence an increasing standard of living for its population. In analyzing the internal mechanism by which the slave system worked, Fogel and Engerman interjected issues for which they offered neither testable hypotheses nor employed the relevant methodological framework.     

The debate on World Dynamics: A response to Nordhaus

In a recent paper published in the Economic Journal, Professor William D. Nordhaus of Yale University reviewed World Dynamics by Jay W. Forrester. In his criticism, Nordhaus signals three serious problems and several additional questionable assumptions of sufficient importance to undermine the usefulness of Forrester's book. However, a careful examination of his analysis shows that each point made by Nordhaus rests on a misunderstanding of World Dynamics, a misuse of empirical data, or an inability to analyze properly the dynamic behavior of the model by static equilibrium methods.The three serious problems raised by Nordhaus concern the assumptions that connect industrialization to net birth rates in World Dynamics, the representation of technology and production within the world model, and the impact of prices on global resource use. The analysis presented here refutes the Nordhaus arguments and shows that World Dynamics is consistent with his references to real-world data on population, production, and capital accumulation.This paper is a response to William D. Nordhaus, World Dynamics: Measurement Without Data, published in the Economic Journal, Royal Economic Society, December 1973. An earlier, unpublished, version of the Nordhaus paper, bearing the same title, was widely circulated hand-tohand within the United States, Canada, and Europe. A response to the original Nordhaus paper (System Dynamics Group Memorandum D-1736-4) was written in February 1973 and is available from Jay W. Forrester, Alfred P. Sloan School of Management, Massachusetts Institute of Technology, Cambridge, Mass. 02139. The present paper, a revised version of the earlier response, deals with several new or modified arguments contained in the Economic Journal article by Nordhaus.