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 An earlier, unpublished, version of the Nordhaus paper, bearing the same title, was widely circulated hand-tohand within the United States, Canada, and Europe.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.