Witnesses

Question 1

General rule

Witness

Answer 1

A witness must have knowledge of the matter she testifies about.

Question 2

Lay Witness

Answer 2

A lay witness must have personal knowledge. Her opinion must be:
1. rationally based on the witnesses perception,
2. helpful to clearly understanding the witness’s testimony or to determining a fact in issue AND
3. NOT based on scientific, technical, or other specialized knowledge within the scope of an expert witness.

Question 3

Exeprt Witness

Answer 3

Does not need personal knowledge but can instead testify based on facts he has been made aware of at trial or through some other means.
may form an opinion of otherwise if:
1. qualified by possessing sufficient knowledge, skill, experience, training, or education
2. the testimony is based on sufficient facts or data
3. the testimony is the product of reliable principles and methods
4. AND the expert has reliably applied the principles and methods to the facts of the case.

Question 4

Expert Witness’ Opinion

Answer 4

An expert may give an opinion regarding an ultimate issue; however, an expert CANNOT give an opinion as to whether a criminal defendant has the requisite mental state for the crime charged (i.e., an expert cannot make decisions intended for the jury).