I analyze two opposing effects of firm dynamics on productivity over the business cycle. Consider net exit, on the one hand it reallocates resources to incumbents whose productivity improves through scale economies, on the other hand it reduces the competitive pressure incumbents face which...

I develop a model of dynamic firm entry, oligopolistic competition and returns to scale in order to decompose TFP fluctuations into technical change, economic profit and markup fluctuations. I show that economic profits cause short-run upward bias in measured TFP, but this subsides to upward...

We develop a model of sluggish firm entry to explain short-run labor responses to technology shocks. We show that the labor response to technology and its persistence depend on the degree of returns to labor and the rate of firm entry. Existing empirical results support our theory based on...

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...