Monetary and time constraints have necessitated the continued use of traditional surveying techniques, despite the tendency of non-probabilistic surveys to yield unrepresentative and biased samples. Unfortunately the lack of information on the extent and nature of this sample bias has made it almost impossible to evaluate the results of such surveys. By examining the results of a traditional and a probabilistic survey of the same area of NE British Columbia, this report quantitatively measures the bias inherent in a traditional, boreal forest survey.