Which statement best describes the basis of an expert's opinion?

Which statement best describes the basis of an expert's opinion?

• A. The facts or data in the case upon which an expert's opinion is based may come from sources in the hearing.
• B. The facts or data may come only from outside the case file.
• C. The basis of an expert opinion is irrelevant to admissibility.
• D. The expert's personal belief alone is sufficient.

Answer: (A)

An expert’s opinion must rest on data or facts the expert reasonably relies on to form the opinion. That data can come from sources presented at the hearing as well as from outside the case file, as long as it’s the type experts in the field would reasonably rely on. This captures why the statement is correct: it reflects that the basis for an expert’s conclusion isn’t limited to what’s already in the record, but can include information the expert has consulted or been exposed to. Why the other ideas don’t fit: opinions aren’t valid merely because they reflect the expert’s personal belief; there must be relevant data or facts the expert has relied upon. Also, the basis of the opinion matters for admissibility—you can rely on information outside the file if it’s the kind professionals in the field would rely on—so saying the basis is irrelevant would be wrong.

An expert’s opinion must rest on data or facts the expert reasonably relies on to form the opinion. That data can come from sources presented at the hearing as well as from outside the case file, as long as it’s the type experts in the field would reasonably rely on. This captures why the statement is correct: it reflects that the basis for an expert’s conclusion isn’t limited to what’s already in the record, but can include information the expert has consulted or been exposed to.

Why the other ideas don’t fit: opinions aren’t valid merely because they reflect the expert’s personal belief; there must be relevant data or facts the expert has relied upon. Also, the basis of the opinion matters for admissibility—you can rely on information outside the file if it’s the kind professionals in the field would rely on—so saying the basis is irrelevant would be wrong.