Using the restrictions implied by the heteroskedasticity of stock returns, we identify four factors in the U.S. industry returns. The first correlates highly with the market portfolio; the second is a portfolio of stocks that produce investment goods minus stocks that produce consumption goods;...

This note provides a simple exposition of what IV can and cannot estimate in a model with a binary treatment variable and heterogeneous treatment effects. It shows how linear IV is a misspecification of functional form and the reason why linear IV estimates for this model will always depend on...

Assortative Matching between workers and firms provides evidence of the complementarities or substitutes in production. The presence of complementarities is important for policies that aim to achieve the optimal allocation of resources, for example unemployment insurance. We argue that using...

Bajari, Benkard and Levin (2007) propose an estimation methodology for a broad class of dynamic optimization problems. To carry out their procedure, one needs to select a set of alternative policy functions and compare the implied expected payoffs with that from the data. We show that this can...

There is much evidence that price-adjustment frequencies vary widely across industries. This paper shows that inflation persistence is lower with heterogeneity in price stickiness than without it, taking as given the degree of persistence in variables affecting inflation. Differences in the...

It is often argued that the New Keynesian Phillips curve is at odds with the data because it cannot explain inflation persistence — the difficulty of returning inflation immediately to target after a shock without any loss of output. This paper explains how a model where newer prices are...