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3D-ID: Geometric Morphometric Classification of Crania for Forensic Scientists

NCJ Number
Date Published
July 2009
27 pages
This paper describes the features, installation, and steps in using the software 3D-ID, which is a cross-platform package that allows forensic practitioners to use established geometric morphometrics (GM) in the determination of the sex and ancestry of unknown cranial remains.
The user provides the program with the Cartesian coordinates of a subset of anatomical points recorded from a cranium of interest. The program then extracts a comparable set of crania of known sex and ancestral classification from a reference database of over 1,000 individuals. It constructs optimized and landmark-specific classification functions based on this reference subset. It attempts to assign the unknown subject to one of the available classes for which there are sufficient reference individuals. Diagnostic values are provided in support of this assignment, along with sample-size-adjusted posterior probabilities of membership in all of the available reference groups, and typicality measures for the unknown with respect to each of the available reference groups. Investigators can then use this information, in addition to other sources, in order to inform their professional assessment of the sex and ancestry of the unknown subject. This report presents step-by-step procedures for program setup and system requirements. Definitions of landmarks are provided, along with details of the GM and statistical methods used in the program. 15 figures and 13 references

Date Published: July 1, 2009