brand dummy variables in hedonic regressions a study using stereo receiver scanner data teague ruder and ted to us bureau of labor statistics april 2004 abstract time are typically used as controls for omitted vari ables the operating assumption made is that dummies control unobserved factors affecting price quality we investigate validity latter by explicitly controlling forsupplyanddemandfactorsinhedonicregressionsforstereoreceiverscannerdata find characteristic coefficients remain roughly unchanged if dustry level supply demand place interact industry with produce manufacturer although physical product char acteristics not significantly changed become quite unstable conclude poorly specified their use adjustment may introduce errors into index calculations keywords measurement market structure jel classification codes l1 d1 l6 thank dan sichel mick silver seminar participants from 2003 nber criw summer insti tute views opinions contained herein be construed
