The Aroma of Tacoma: Time-Varying Average Derivatives and the Effect of a Superfund Site on House Prices.

A variant of the average derivative estimator is developed to construct an index measuring the effects of a copper smelter on house prices in Tacoma, Washington. The estimated average derivative index is smooth and has lower standard errors than regression coefficients estimated separately across discrete time periods. The dataset spans the time of initial rumors of Superfund site designation, the closing of the smelter, Superfund site designation, and the start of cleanup operations. The addition of the smelter to the Superfund site and the subsequent plant closing converted the price discount associated with smelter proximity to a premium.