Forensic hair examinations are most frequently conducted to assist investigation and prosecution of crimes of violence such as murders and sexual assaults. Although the probative value of hair comparison is generally much lower than that of some other forms of forensic evidence such as fingerprints or DNA, it can still provide good corroborative evidence. Hair comparison can help establish associations between any combinations of the following: accused, victim, crime scene or weapon.

There is a consensus that hair examination can yield reliable information about class characteristics of hair strands. Experts can identify major as well as secondary characteristics. The former includes features such as colors, shaft form, and hair diameter.