Experts Flashcards
Lay Opinions
if a witness is NOT testifying as an expert, testimony in the form of an opinion is limited to one that is: (1) rationally based on witnesses perception; (2) helpful to clearly understand the witness’ testimony or to determining a fact in issue; (3) not based on scientific, technical, or other specialized knowledge within the scope of Rule 702.
Expert Witnesses
A qualified expert who that testifies as a witness may testify in the form of knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:
(1) The expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue
(2) The testimony is based on sufficient facts or data
(3) The testimony is the product of reliable principles and methods; and,
(4) The expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.
Determining Reliability under No. 3
Frye: Reliable if the expert’s approach is “generally accepted evidence” within the field.
Daubert: Reliable if the scientific expert’s testimony must be “relevant and reliable”.
Daubert Factors: (non-exhaustive. Do not have to have all 5)
Whether the principle/method has been tested ‘
Whether principle/method has been subjected to peer review/publications
Whether there is known (low) error rate
Whether standards control application
General acceptance
Standard: abuse of discretion, No reasonable trial judge would have found what this trial judge did.
Basis of an Expert Opinion
General Rule: An expert may state an opinion and give reasons for it without testifying to the underlying facts or data. But the expert may be required to disclose those facts or data on cross-examination. QE’s can rely on both inadmissible/admissible evidence and do not need personal knowledge to testify.
→R/E: If experts in the particular field would reasonably rely on those kinds of facts or data in forming an opinion on the subject, they need not be admissible for the opinion to be admitted.
→ R/E: If Disclosure of those facts to the jury:
When inadmissible: admissible under reverse 403 (if their PV in helping jury evaluate the opinion substantially outweighs UP)
Even when admitted, not admitted for their truth.
When admissible: can come in
General Expert Questions
1) What topics are appropriate for ET?
A: Where expert opinion will help the fact-finder 702(a)
2) Who may testify as an expert?
A: Anyone who has special knowledge via training or experience (702)
3) Is testimony reliable?
A: Anyone who has special knowledge via training or experience (702)
4) What data may experts rely on in forming opinion?
A: Admissible facts + inadmissible facts that those in the field reasonably rely on 702(b) → 703
5) Should the jury hear facts on which expert bases opinion?
Admissible facts, yes
Inadmissible: then reverse 403
Doesn’t matter if you submit the basis for the opinion and then opinion or reverse. Just as long as you do it (705).
(6) Should the form of expert opinion testimony be restricted
A: Ultimate issue ok, except criminal defendant’s mental state (704)
Whether/when to disclose basis of evidence is up to the proponent/judge. Opponent can always ask about basis.
