Expert Testimony

Question 1

Why Is It Useful for a Witness to be Deemed an Expert?

Answer 1

• Their testimony is bound by FRE 702, not FRE 701.
  
  • This allows them to offer their opinions on the matter as it relates to their field of expertise and means that they aren’t limited to first-hand knowledge.
• Jurors tend to trust expert witnesses more than other witnesses.
• They aren’t bound by hearsay rules.
• The proponent of the expert witness will appear to be well-prepared.

Question 2

Who Can Be an Expert?

Answer 2

• Advisory Committee note to FRE 702 says that “within the scope of this rule are not only experts in the strictest sense of the word, e.g., physicians, physicists, and architects, but also the large group sometimes called ‘skilled’ witnesses, such as bankers or landowners testifying to land values.”
• A prisoner could be an expert about prison slang and a drug dealer could be an expert about drug packaging.
• Key question is whether the judge, following FRE 702, will certify a particular witness as an expert on a particular subject.
• The proponent must lay a foundation by showing that the witness:
  1. Has particular knowledge, skill, expertise, training, education, etc.
  2. Is relying on valid principles or techniques that have been applied appropriately in this case
  3. Has something to offer that is useful for the jury
• Once designated an expert, a witness is only an expert when the witness is testifying on those subjects within their expertise.
• Be aware that “professional expert witnesses” exist and can be impeached for bias based on their fees, general loyalty to one side, or other reasons.

Question 3

Daubert Test

Answer 3

• Daubert v. Merrell Dow Pharmaceuticals (1993) threw out Frye’s “general acceptance” test.

Daubert Factors:

1) Can the expert’s technique or theory be tested?

2) Has the technique or theory been subject to peer review and publication?

3) What is the known or potential rate of error of the technique or theory when it was applied?
- It’s better to have a 40% error rate than to have no known error.

4) Are there existence and maintenance of standards and controls?

5) Has the technique or theory been generally accepted in the scientific community?

Question 4

FRE 702: Testimony by Expert Witness

Answer 4

• “A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the proponent demonstrates to the court that it is more likely than not that:

(a) 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;

(b) the testimony is based on sufficient facts or data;

(c) the testimony is the product of reliable principles and methods; and

(d) the expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.

• Expert witnesses aren’t limited to their personal knowledge when testifying and thus are permitted to offer opinions, but their opinions are limited to their field of expertise and the techniques and theories used to arrive at these opinions must pass a factor test listed above.
• 2023 Amendments to FRE 702:
  • Clarified that proponent of expert testimony bears burden of demonstrating by preponderance of evidence that proposed testimony meets all the reliability requirements set forth in FRE 702. The judge, not the jury, determines whether proponent’s showing is sufficient for admission of expert testimony.
  • Another amendment required the proponent of expert testimony to demonstrate that “the expert’s opinion reflects a reliable application of the principles and methods” the expert has used. This requirement would extend the current language, which only requires that the expert reliably applied the principles and methods (e.g., through out-of-court testing), but not that of the opinion itself is a reliable application of those principles and methods.

Question 5

FRE 701: Opinion Testimony by Lay Witnesses

Answer 5

• If a witness is not testifying as an expert, testimony in the form an opines limited to one that is:
  (a) rationally based on the witness’s perception;
  (b) helpful to clearly understanding the witness’s testimony or to determining a fact in issue; and
  (c) not based on scientific, technical, or other specialized knowledge within the scope of Rule 702.
• In sum, lay witnesses cannot testify about anything other than what they have rationally perceived.

Question 6

FRE 703: Bases of an Expert

Answer 6

• Experts can base their opinion on facts or data in the case that they’re aware of or personally observed if other experts in their field would base their opinions on those facts, but these facts can’t be disclosed to the jury unless the probative value of these facts substantially outweighs their prejudicial effect (read: Reverse 403 Balancing Test).
• Note: the opponent has no trouble inquiring about underlying facts, even if they are inadmissible.

Question 7

FRE 704: Opinion on an Ultimate Issue

Answer 7

• FRE 704(a): An expert witness can testify about an element of a tort claim, element of an affirmative defense, element of a crime, etc., but this testimony is still subject to the Rule 403 Balancing Test.
• FRE 704(b) (the “Hinckley Rule”): An expert witness cannot testify about the mental state of a criminal defendant as it relates to the mens rea element of a crime; they could discuss that people with similar mental illnesses often experience delusions or similar statements, but they cannot make definitive statements about a defendant’s intent, knowledge, etc. or lack thereof.

Question 8

FRE 705: Disclosing the Facts or Data Underlying an Expert

Answer 8

• An expert doesn’t have to disclose the specific facts or data that give reason to their testimony, but they do have to give reason to their testimony and can be cross-examined for the specifics.

Question 9

FRE 706: Court-Appointed Expert Witnesses

Answer 9

• On a party’s motion or on its own, the court may appoint an expert witness, but they must be a willing expert and they must be justly compensated; they can then be deposed by any party, be called to testify, cross-examined, etc. and the parties will bear the costs of the appointment unless it’s a criminal case or a civil case involving just compensation under the Fifth Amendment.