W ITHIN recent years several lines of adI,/'VTvance in quantitative economic research have converged to focus attention upon the deflation of value added and, where the data relating to the desired social accounting concept are available, gross product originating by industry. The common proximate goal of such endeavors has been to secure measures of the contribution made by various industries or sectors of the economy to real national product. Estimates of real product on an industry basis are held to be useful on a number of counts. They may be aggregated to provide a check on the results of the deflation of gross national product by expenditures on goods and services in the major categories of final demand. Moreover, not only do they offer a means of analyzing the industrial composition of historical and contemporary changes in total real and aggregate productivity, but they form a basis for the incorporation of industrial detail into current economic projections.' Working toward these ends, the Canadian Dominion Bureau of Statistics has prepared annual and quarterly indices of industry net output by deflating census value added. The indices have been used to project estimates of gross domestic product by industry of origin available for bench-mark dates.2 The United States has not been inactive on this front. A cooperative governmental project, undertaken at the request of the Interagency Subcommittee on Production and Productivity (Office of Statistical Standards, Bureau of the Budget) has carried out exploratory work developing annual estimates of constant dollar gross product originating by industry.3 In still another quarter, American economic historians have recently been presented with estimates of major sector real commodity in the United States during the latter two-thirds of the nineteenth century. These were prepared by Robert Gallman through the deflation of (state and federal) census value added data.4 In the light of these developments wlhich not only portend, but seem certain to encourage, continued pursuit of the industry real product approach, it will perhaps be useful to consider the implications of the accepted statistical procedure for deflating value added and gross product originating. As it is usually defined, current dollar value added is the value of gross sales, at producers' prices, less the cost of raw materials (including fuel and energy) purchased from other industries (and/or firms within the same industry), at delivered prices. Gross product originating can be defined as the market value of the industry's output, less the expenditure on purchases of all intermediate goods and services.5 It is a direct step from the current value definition to the derivation of constant dollar value added, CDVA, by the ith industry in year t as