Which type of evidence requires a comparison to establish its value?

The type of evidence that requires a comparison to establish its value is tire marks. This is because to determine whether a particular tire mark at a crime scene matches a specific vehicle, forensic experts will analyze various characteristics of the tire tread pattern, including size, shape, and unique features. This comparison can help establish a link between a vehicle and the crime scene, enhancing the evidence's value in an investigation.

Tire marks are often unique to specific makes and models of tires, with certain manufacturers producing distinctive tread designs. By matching a tire mark from the scene to those of a suspect's vehicle, investigators can gather significant evidence that supports or disputes a suspect's involvement in a crime. This emphasis on comparison is fundamental in forensic science, as it allows for objective evaluations based on observable characteristics.

In contrast, fingerprints and blood samples can provide direct identification or exclusion without the need for a comparative evaluation with an external sample. Witness testimonies are based on personal accounts and do not involve comparison in the same forensic sense; instead, their reliability is assessed through corroboration and consistency, not direct comparison to another piece of evidence.