RESOURCE AND OUTPUT TRENDS IN THE UNITED STATES SINCE 1870 By MosES ABRAMOVITZ Stanford University I. Introduction <u This paper is a very brief treatment of three questions relating to ne history of our economic growth since the Civil War:(1)How large has been the net increase of aggregate output per capita, and to what extent has this increase been obtained as a result of greater labor or capital input on the one hand and of a rise in productivity on the other? (2)Is there evidence of retardation, or conceivably acceleration, in the growth of per capita output?(3)Have there been fluctuations in the rate of growth of output, apart from the short-term fluctuations of business cycles, and, if so, what is the significance of these swings? The answers to these three questions, to the extent that they can be given, represent, of course, only a tiny fraction of the historical ex perience relevant to the problems of growth. Even so, anyone ac quainted with their complexity will realize that no one of them, much all three, can be treated satisfactorily in a short space. I shall have to pronounce upon them somewhat arbitrarily. My ability to deal with them at all is a reflection of one of the more important, though one of the less obvious, of the many aspects of our growing wealth; namely, the accumulation of historical statistics in this country during the last generation. For the most part, the figures which i present or which unde erle n qualitative statements are taken directly from tables of estimates of national product, labor force, productivity, and the like compiled by others. In a few cases i have ventured to compute ratios or extend the tables forward or backward by combining estimates. But no original estimates depending on the compilation or reworking of primary data are included * I should like to thank Professor Sir It is to be reprinted as no. 52 in the National Bureau s series of Occasional Papers