In the literature, comparisons between absolute levels of productivity in different industries occur frequently. This paper explores the meaning and possible significance of such measures. Prices must be used to permit the required comparison of the outputs of different industries. It is shown that base-year weights produce a valid measure of productivity growth but not of absolute productivity level. Current price weights do yield a valid index of absolute productivity but one that tends to be equal for all industries because of the general equilibrium mechanism that reallocates resources from low-productivity to high-productivity industries.

[Energy-production subsidies are, paradoxically, shown to be likely to increase U.S. dependence on imported oil. Standard studies of net energy yields are shown to be seriously biased upward for two reasons. First, many omit indirect energy inputs, which, our input-output calculation shows, probably causes large errors. Second, those studies all omit the energy opportunity costs of nonenergy inputs (e.g., the fuel substituted elsewhere for the labor used to produce energy). We prove that, absent externalities, any fuel-output subsidy which causes an otherwise unprofitable expansion must yield an incremental fuel output smaller than the increment in energy input plus the energy opportunity costs of other inputs.]

Puerto Rico's transformation from a preindustrial to an industralized economy in the period 1948-63 provides an opportunity to measure the impact of technological change on several basic parameters in a Marxian economic framework. The rate of surplus value (estimated using the Morishima-Seton transformation) remains relatively stable at 0.97 in 1948 and 0.93 in 1963, while the organic composition falls from 2.75 to 2.09. The stability in the rate of surplus value results from a 63 percent average fall in labor values counterbalanced by a 143 percent rise in labor's consumption. The rate of surplus value, when adjusted for trade flows, jumps to 1.31 in 1948 and 1.18 in 1963, due to Puerto Rico's large balance-of-trade deficit and the relative import intensity of labor's consumption.

In the literature, comparisons between absolute levels of productivity in different industries occur frequently. This paper explores the meaning and possible significance of such measures. Prices must be used to permit the required comparison of the outputs of different industries. It is shown that base-year weights produce a valid measure of productivity growth but not of absolute productivity level. Current price weights do yield a valid index of absolute productivity but one that tends to be equal for all industries because of the general equilibrium mechanism that reallocates resources from low-productivity to high-productivity industries.

Energy-production subsidies are, paradoxically, shown to be likely to increase U.S. dependence on imported oil. Standard studies of net energy yields are shown to be seriously biased upward for two reasons. First, many omit indirect energy inputs, which, our input-output calculation shows, probably causes large errors. Second, those studies all omit the energy opportunity costs of nonenergy inputs (e.g., the fuel substituted elsewhere for the labor used to produce energy). We prove that, absent externalities, any fuel-output subsidy which causes an otherwise unprofitable expansion must yield an incremental fuel output smaller than the increment in energy input plus the energy opportunity costs of other inputs.