Lay & Expert Testimony

Question 1

Lay Opinion - General Rule

Answer 1

If a witness is not testifying as an expert, testimony in the form of an opinion is limited to one that is:

• Rationally based on the witness’ perception
• Helpful to clearly understand the witness’ testimony or to determine a fact in issue; and
• Not based on scientific, technical, or other specialized knowledge

Question 2

Sample areas lay opinion okay

Answer 2

Usually see handwriting or voice

• Identity
• Handwriting
• Value, weight, measure, quantity
• Time, distance, velocity
• Size, age, strength
• Can estimate a car’s speed
• Heat, cold
• Sickness, health
• Disposition
• Anger, fear, calm, excitement
• Intoxication – alcohol, smell of marijuana, but not whether you think someone is under influence of a certain drug

Question 3

Expert Opinion

Answer 3

(what makes you so smart - ex. Marisa Tomei clip)

A witness is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion of otherwise if:

(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) Testimony is based on sufficient facts or data
(c) Testimony is product of reliable principles and methods; and
(d) The expert has reliably applied the principles and methods to the facts of the case

Question 4

When can expert testify

Answer 4

If what the expert says will assist the trier of fact to understand the evidence or to determine a fact in issue

Question 5

What is basis for expert opinion:

Answer 5

An expert may base on opinion on facts/data in case that expert has been made aware of or personally observed

o Learns by listening at trial

• Expert can sit in on trial and learn facts while listening to testimony
• Information made known to an expert

o Rely on data by experts within the field, regardless of facts mentioned at trial

o Can rely on hearsay data – statements made by other people/witnesses

• Subject to judge’s discretion

Question 6

Expert Opinion - Opinion on ultimate issue

Answer 6

General Rule: not automatically objectionable

• An opinion is not objectionable just because it embraces an ultimate issue

• Cannot speak to whether person criminally insane at the time committed offense. Can speak to person lacking ability to know difference between right/wrong, and jury can infer that person was insane.

Question 7

Expert Opinion Presentation

Answer 7

Ask expert to explain background, training, experience. Give opinion relevant to case. How did you form that opinion, base it on?

Question 8

Scientific Evidence (Daubert v. Merrell Dow Pharmaceuticals)

Answer 8

2 requirements for scientific evidence

(1) Reliability: Considered reliable within the community

o 1. Can it be tested
o 2. Publication, peer review
o 3. Known or potential rate of error
o 4. Standards governing the technique’s operation 
o 5. General acceptance

• Want solid foundational principles that people in industry rely on

(2) Evidence must fit the case

• Relevant
• Must bear sufficiently on the points in issue to aid the jury in its fact finding task

Question 9

Modern science in the courtroom

Answer 9

Allow:

o Battered child syndrome

o Child sexual abuse accommodation syndrome

o Rape trauma syndrome

o Battered woman syndrome

o DNA