Qualifying as an Expert Witness in California

Individuals can be qualified as an expert witness in California courts, just as they can in federal and other states’ courts as well. Expert testimony is provided by one or both of the parties to a lawsuit and, as a general rule, the evidence offered by the expert’s testimony must be reliable and relevant, and must assist the trier of fact in order to be admissible.

Under the federal Rules of Evidence, Rule 702, expert witnesses in court must have “knowledge, skill, experience, training, or education” that will “help the trier of fact to understand the evidence or to determine a fact in issue.”

As a result, Rule of Evidence 702 requires that an expert be qualified as an expert, that his or her testimony address a subject that the finder of fact (court or jury) can be assisted by through the testimony of the expert, and that the expert’ testimony is reliable.

California Evidence Code Section 720 provides the following:

(a) A person is qualified to testify as an expert if he has special knowledge, skill, experience, training, or education sufficient to qualify him as an expert on the subject to which his testimony relates. Against the objection of a party, such special knowledge, skill, experience, training, or education must be shown before the witness may testify as an expert.

(b) A witness’ special knowledge, skill, experience, training, or education may be shown by any otherwise admissible evidence, including his own testimony.

So, the expert witness in a California court of law is required to have “special knowledge, skill, experience, training, or education,” just like under federal law. In order to qualify as an expert witness, that person is asked about their specialize knowledge, training and education in that specialty area, any research or publications, or licenses, for example, that the expert may possess.

What is the purpose of qualifying as an expert witness? Again, it is to assist the trier of fact in understanding an aspect of the case. In other words, the particular subject matter to which the expert will testify is not a subject matter of common experience or understanding to the average person. In those instances of technical or specialized subject matters, a layperson would not be qualified to testify about that subject matter.

In general, witnesses called to testify at a bench (before a judge) or jury trial are limited to testifying about what they heard or saw. On the other hand, an expert witness can draw a conclusion and give their opinion in their testimony. The expert is not limited in their testimony to what they heard or saw.

As a result, an expert draws upon their experience, training, education, expertise, etc. to give their opinion. That expert opinion assists the judge or jury in making its decision.