This paper presents an aggregate demand-driven model of business cycles that provides a new explanation for the procyclicality of productivity and simultaneously predicts large welfare losses from monetary nonneutrality. The key features of the model are an input-output production structure, imperfect competition, countercyclical markups, and for some results, state-dependent price rigidity. True technical efficiency is procyclical even though production takes place with constant returns, without technology shocks or technological externalities. The paper has observable implications that distinguish it empirically from related work. These implications are generally supported by data from U.S. manufacturing industries.

Yes. We construct a measure of aggregate technology change, controlling for aggregation effects, varying utilization of capital and labor, nonconstant returns, and imperfect competition. On impact, when technology improves, input use and nonresidential investment fall sharply. Output changes little. With a lag of several years, inputs and investment return to normal and output rises strongly. The standard one-sector real-business-cycle model is not consistent with this evidence. The evidence is consistent, however, with simple sticky-price models, which predict the results we find: when technology improves, inputs and investment generally fall in the short run, and output itself may also fall.