This chapter reviews and synthesizes our current understanding of the shocks that drive economic fluctuations. The chapter begins with an illustration of the problem of identifying macroeconomic shocks, followed by an overview of the many recent innovations for identifying shocks. It then...

Structural vector autoregressions give conflicting results on the effects of technology shocks on hours. The results depend crucially on the assumed data generating process for hours per capita. We show that the standard measure of hours per capita has significant low frequency movements that...

This paper investigates the source of historical fluctuations in annual US data extending back to the late 19th century. Long-run identifying restrictions are used to decompose productivity, hours, and output into technology shocks and non-technology shocks. A variety of models with differing...