A witness who qualifies as an expert because of knowledge, skill, experience, training, or education may testify as an expert if scientific, technical, or other specialized knowledge will assist the judge, jury, or other factfinder to understand the evidence or determine a contested fact issue.

But there is no rigid formula for determining whether a particular witness is qualified to testify as an expert. Generally there must be a fit between the subject matter at issue and the expert witness’s familiarity with the subject matter. And this determination is made by the judge, who acts as a gatekeeper to only allow reliable expert witness testimony to be heard and considered by the judge or jury.

In Utah, as in many jurisdictions, the admissibility of expert witness testimony is governed by rules that are similar to the federal rules of evidence. Specifically, Utah Rule of Evidence 702 provides the framework for when an expert witness may testify in court. According to this rule, a witness who has specialized knowledge, skill, experience, training, or education may be permitted to testify as an expert if their expertise will help the court to understand the evidence or to determine a fact in issue. The determination of whether a witness qualifies as an expert is not based on a strict formula but rather on whether there is an appropriate fit between the witness's expertise and the subject matter of the dispute. The judge in the case serves as a gatekeeper, assessing the reliability of the expert's testimony and deciding whether it should be presented to the jury. This gatekeeping function is crucial to ensure that only relevant and reliable expert testimony is considered in the legal proceedings.