Further evaluation of probabilities in human scalp hair comparisons

Placing value on associative hair evidence is an integral part of court presentation. A modified repeat of the hair probability study by Gaudette and Keeping has been undertaken, with steps taken to remedy shortcomings of the original work. The results of this study demonstrate that, with the application of rigid selection criteria, the frequency of coincidental matches in forensic science hair comparisons is low. It also demonstrates that routine hair classification is not feasible, because of inconsistency in examiner discrimination. The macroscopic selection of 5 to 13 mutually dissimilar hairs has been shown to be frequently unrepresentative of the microscopic range of features present in a known hair sample.