Aggregate productivity and aggregate technology

Aggregate productivity and aggregate technology are meaningful but distinct concepts. We show that a slightly modified Solow productivity residual measures changes in economic welfare, even when productivity and technology differ because of distortions such as imperfect competition. Our results imply that aggregate data can be used to measure changes in welfare, even when disaggregated data are needed to measure technical change. We then present a general accounting framework that identifies several new non-technological gaps between productivity and technology, gaps reflecting imperfections and frictions in output and factor markets. Empirically, we find that these gaps are important, even though we abstract from variations in factor utilization and estimate only small average sectoral markups. The evidence suggests that the usual focus on one-sector DSGE models misses a rich class of important propagation mechanisms that are present only in multi-sector models. (C) 2002 Elsevier Science B.V. All rights reserved.