Intro to the Federal Rules of Evidence - 37

2. Opinion testimony by experts (FRE 702)

a. Requirements
i) Subject matter must be appropriate for expert testimony: “assist the trier of fact”
1) The opinion must be relevant (i.e., it must fit the facts of the case)
2) The methodology underlying the opinion must be reliable (FRE 702)
a) The opinion is based on sufficient facts or data
b) The opinion is the product of reliable principles and methods
c) The expert has reliably applied the principles and methods to the facts of the case
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).
ii) Witness must be qualified as an expert (FRE 702)
iii) Opinion must be supported by proper factual basis (FRE 703, FRE 705)
1) Personal observation
Typical examples are the forensic chemist who analyzes and testifies about the nature of a controlled substance or the treating physician who testifies about the cause and extent of an injury.
2) Facts made known to expert at or before trial
An expert witness may testify about admitted evidence (record facts).
3) Facts made known to expert outside court
An expert may give an opinion based on information supplied to the expert outside the recorded facts, if of a type reasonable relied upon by experts in the particular field.

FRE 703 permits an expert to base an opinion on hearsay information, but it does not recognized a hearsay exception for this information (refer to the 3rd sentence of FRE 703).

b. Opinion may embrace ultimate issue (FRE 704)
Opinions on ultimate issues are allowed except when they relate to the mental state of a criminal defendant (FRE 704(b)).

c. Authoritative texts and treaties (FRE 803(18))
If admitted, the statements may be read into evidence but may not be received as exhibits (i.e., the jury never sees it.)
The treatise itself is not admissible as an exhibit under FRE 803(18).

EXAMPLE: (using treaties during the direct examination of experts)
Q: Dr. Spencer, as part of your evaluation of this case, did you rely on any treatise in your field?
A: Yes.
Q: Which one?
A; I relied in part on a standard treatise, Saunders on Obstetrics.
Q: Is Saunders on Obstetrics recognized as a reliable authority in your field?
A: Absolutely. It’s probably the most-used treatise in obstetrics today.
Q: Did you rely on any statement in Saunders on Obstetrics during your evaluation of this case?
A: Yes.
Q: Do you have that treatise with you?
A: Yes [holds up treatise], it’s been marked as Plaintiff’s Exhibit No. 3. I relied particularly on page 353, the section called “Disturbances in the Newborn – Asphyxia.” That’s the section I found particularly useful.
Q: Your honor, at this time we ask that Dr. Spence be allowed to read those statements from the treatise that he relied on in reaching his conclusions.
JUDGE: He may. Proceed.
Q: Dr. Spence, please read those statement.
A: On page 353 of the treaties, it says …