AFTE Store - How Unique Are Impressed Toolmarks? An Empirical Study of 20 Worn Hammer Faces

The validity of Rocky Stone’s previously published theories on the statistical uniqueness of impressed toolmarks is tested through the empirical examination of the defects observed on the faces of twenty hammers that had been subjected to various degrees of wear and abuse through normal use. These examinations were carried out under controlled conditions that would simulate those used in practical casework. The results of this study have led to a re-evaluation of Stone’s work and a modification of related formulae. The revised formulae are used to calculate practical but conservative probabilities associated with impressed toolmarks using the data collected from the hammers in this study.

Full Journal: AFTE Journal Vol 37 No 4 (2005)