Slow firm entry over the business cycle causes measured TFP to vary endogenously because incumbent firms bear shocks. Our main theorem states that imperfect competition and dynamic firm entry are necessary and sufficient conditions for these endogenous productivity fluctuations. The result...

We apply a range of models to the U.K. data to obtain estimates of the output gap. A structural VAR with an appropriate identification strategy provides improved estimates of output gap with better real time properties and lower sensitivity to temporary shocks than the usual filtering...