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When Is an Expert Witness Necessary in Civil Litigation in Colorado and Denver Courts

Generally speaking an expert witness is a witness that has special knowledge, skill, experience, training, or education that allows him or her to give opinion testimony for facts at issue in a case. See Colorado Rule of Evidence (“C.R.E.”) 702; C.R.E. (703).

Examples of areas where expert testimony is frequently used to help clarify or render an opinion on facts at issue in the case are medical experts for physical injuries; scientific experts for things such as DNA analysis and accident reconstruction; and economic experts to establish damages a plaintiff or defendant has suffered.

Importantly, expert testimony is not necessary in all cases. Indeed, C.R.E. 702 provides that an expert may testify where “scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or determine a fact in issue.” That is, the rule does not require expert testimony in all cases, but instead a party may provide expert testimony if it will assist the trier of fact. Accordingly, expert testimony is generally used where highly technical subject matter is at issue that a lay person or somebody who doesn’t have specific training in a particular field would have difficulty understanding the facts at issue.

However, despite C.R.E. 702 indicating that expert testimony is generally optional, there are some specific cases where expert testimony is necessary in order to prove a claim or defense. A specific example of this is malpractice claims asserting negligence against a professional. In particular, in order to establish negligence, the party asserting it needs to demonstrate that the defendant owed the plaintiff a standard of care and breached that standard of care.

For example, in medical malpractice and attorney malpractice cases an expert witness is necessary to establish what the standard of care is and whether the defendant breached that standard. Additionally, since lay witnesses can only testify to as to their own perceptions and inferences based on those perceptions – and cannot testify to opinions based on scientific, technical, or other specialized knowledge – expert witnesses will also be necessary where scientific or technical opinions need to be admitted in order to prove a claim or defense. See C.R.E. 701; Your First Expert Witness-Part I, 40 Colo.Law. 93 (2011); Your First Expert Witness-Part II, 40 Colo.Law. 93 (2011).


The Line between Lay Witness Testimony and Expert Witness Testimony

The line between lay witness and expert witness testimony can often be hard to discern. There is little doubt that where an opinion is based on highly scientific or technical subject matter – for example, DNA tests, medical injuries, etc., that opinion may only be given by a witness qualified as an expert. However, where an opinion is based on specialized knowledge acquired over time that is not necessarily scientific or technical in nature, the line becomes less clear.

As an example, police officers frequently give opinion testimony that is based off of their training and experience as law enforcement officers yet they do not have to be qualified as expert witnesses. Examples of this type of testimony are giving an opinion as to the speed of an observed car and giving an opinion as to a person’s sobriety. Courts have found that police officers may give opinion testimony in these areas without being qualified as an expert witness. Seemingly, this is because observations of speed and sobriety are common enough to everyday life that “ordinary citizens can be expected to have known the information or have had the experiences that form the basis of the opinion.” People v. Ramos, 2012 COA 191 at ¶12 (Colo. 2012).

Accordingly, at its most basic, the line between whether a witness needs to be qualified as an expert or can testify as a lay person arises where the witness is going to give opinion testimony based on specialized knowledge that is not common to the average person. See Rules 701 and 702 : Boundary Between Lay and Expert Opinion Testimony, 34 Colo. Law. 53 (July 2005). If the opinion testimony is outside the scope of what people commonly experience or are familiar with, then the witness needs to be qualified as an expert before giving that testimony.

Other factors to consider, which are by no means exhaustive, are: (1) whether the testimony is based on first-hand knowledge or relies upon prior experience, (2) whether technical terms need to be defined during the testimony, and (3) the extent to which the witness relies upon training and experience to come up with her opinion. People v. Ramos, 2012 COA 191 at ¶18-22 (Colo. 2012).

© 2016 J.D. Porter, LLC; Jordan Porter. Denver, Colorado.

Disclaimer: The information on this website is intended to be general information only and not legal advice. Laws change frequently and the information on this website may not be up to date, nor is the information intended to be fully comprehensive. For legal advice specific to your case please contact J.D. Porter, LLC or another licensed attorney.