What is a forensic 'comparison analysis' of physical evidence?

What is a forensic 'comparison analysis' of physical evidence?

Richard Saferstein (Former Chief Forensic Scientist) gives expert video advice on: What is forensic science?; What is forensic 'physical evidence'?; What is forensic 'identification' of physical evidence? and more...

Comparison is quite different than the "what is it" identification. The purpose of the comparison is to make a determination as to the common origin of items of evidence. Did the hair in the crime scene come from the head of a particular suspect? Did a fingerprint found at a crime scene come off the fingers of a certain person who was suspected of being the perpetrator? We undertake comparisons for the purposes of determining common origin.