What is the difference between class evidence and individual evidence, and give an example of each?

What is the difference between class evidence and individual evidence, and give an example of each?

• A. Class evidence narrows to a single source; fingerprint is individual evidence
• B. Class evidence narrows to a group (e.g., blood type); fingerprint is individual evidence
• C. Class evidence narrows to a group (e.g., blood type); hair is class
• D. Class evidence and individual evidence refer to the same concept

Answer: (B)

Class evidence narrows the search to a group of sources that share a common property, rather than pinpointing a single source. Blood type is a classic example of class evidence because many people have the same ABO/Rh type, so finding that blood type at a crime scene can limit the pool to those who share that group characteristic, but it cannot identify one person by itself.

Individual evidence, on the other hand, has a unique attribute that can link to a single source. Fingerprints are a prime example because the pattern of ridges on a finger is highly distinctive to an individual, making it possible to tie a specific print to one person with a strong degree of certainty (aside from exceptional coincidences).

So the difference is that blood type narrows to a group, while a fingerprint can point to a specific person.