Difference-in-Differences Hedonics

Cross-sectional estimates of hedonic price functions theoretically recover marginal values for characteristics but face endogeneity problems. Consequently, economists have introduced difference-in-differences and other quasi-experimental econometric methods into hedonic models. Unfortunately, the welfare interpretation of these estimands has not been clear. This paper shows that quasi-experimental hedonics can identify the movement along the ex post price function. It further shows that this effect is a lower bound on general equilibrium welfare. Thus, nonmarginal welfare can be recovered using transparent designs without Rosen's second stage or more structural models. The paper illustrates these results with an application to toxic facilities and housing prices.