Statistical evaluation of morphological data of Japanese head hair and the screening of evidential hair samples by cluster analysis.
Intra-individual and inter-individual variations in Japanese head hair morphology were reevaluated and the screening of evidential hair samples using a statistical method was investigated. A quantification of the morphological data was used as a system in which morphological features obtained by macroscopic and microscopic observations can be objectively processed in the form of numerical information. For confirming the availability of morphological features for hair comparison, the inter-individual comparison of ten male Japanese was investigated by discrimination analysis using 18 variables including five original numerical morphological features (variables) and 13 variables obtained from six morphological features by quantification. The majority of the comparisons showed a high level of discrimination between two individuals. For morphologically narrowing down the number of evidential hair samples collected from a crime scene, a screening method was investigated by cluster analysis using 18 variables. In an experimental model of evidential hair samples derived from 20 individuals, hair samples from 13 individuals were successfully discriminated using the cluster analysis described in the present investigation.
Sato
Hajime
H
National Research Institute of Police Science, Kashiwanoha 6-3-1, Kashiwa, Chiba 277-0882, Japan.