It is shown in this letter that the measured velocity‐electric field (v‐E) characteristic ofn‐type GaAs differes substantially from the intrinsicv‐Echaracteristic if the doping density of the sample is nonuniform. A simple analysis of the effect is given which compares favorably with a more complete calculation and with experimental results. The heretofore unexplained large variation in measuredv‐Echaracteristics is readily predicted by the present theory if reasonable assumptions are made regarding sample inhomogeneity.