Witnesses Flashcards
Lay Opinion
An OPINION by a lay witness is usually inadmissible UNLESS:
* (i) it’s rationally based on witness’s perception
* (ii) it’s helpful to the trier of fact
* (iii) it’s not based on science/specialized knowledge
Expert Opinion
Expert witness can provide opinions IF:
* (i) witness is qualified as expert (has sufficient special knowledge, skill, experience, training, or education)
* (ii) witness is reasonably certain about the opinion
* (iii) subject matter is where scientific, technical, specialized knowledge would be helpful to the jury
* (iv) opinion is based on sufficient facts/data
* (v) opinion is based on expert’s reasonable application of reliable methods and principles
Opinion is based on sufficient facts IF:
* (i) facts were based on expert’s personal observation (ex. doc examined P)
* (ii) facts were presented in evidence at trial
* (ii) facts are of a type reasonably relied on by other experts in that field
Reliable methods and principles:
* FRE: Daubert standard - examines expert’s theory or methodology (scientific and non-scientific expert opinions)
* CEC: Frye standard - whether opinion is based on scientific principles that are generally accepted in the relevant field (scientific expert opinions only)
Opinion can refer to ultimate issue in civil case
Expert’s theory or methodology - can consider various factors, including:
* Whether it has been tested;
* Publication/peer review;
* Error rate; and
* Whether it is generally accepted in the relevant field.
