Which description best defines an expert witness?

• A. A witness who tests scientific methods.
• B. A witness who has knowledge not normally possessed by the average person.
• C. A witness who testifies about facts only.
• D. A lay witness.

Answer: (B)

An expert witness is defined by having specialized knowledge or training beyond what the average person possesses, which allows them to interpret complex evidence and provide informed opinions to help the court understand technical issues. This matches the idea of a witness who has knowledge not normally possessed by the average person. Experts can explain methodologies, evaluate results, and discuss limitations, offering conclusions grounded in their expertise rather than just recounting observations. In contrast, a lay witness testifies about facts only, describing what they directly perceived. Merely testing scientific methods doesn’t by itself define someone as an expert, and describing facts aligns more with a non-expert witness.