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—and to exclude such testimony when it is not reliable.

In Nevada, expert witness testimony is governed by rules that allow individuals with specialized knowledge, skill, experience, training, or education to provide their expert opinion in court if it can help the judge or jury understand the evidence or resolve a contested fact. The determination of whether a witness qualifies as an expert is not based on a strict formula but rather on the relevance and fit of the witness's expertise to the subject matter of the case. The judge serves as a gatekeeper, assessing the reliability of the expert's testimony and deciding whether it should be admitted for consideration. This gatekeeping role is crucial to ensure that only pertinent and reliable expert testimony is presented, thereby maintaining the integrity of the judicial process. Nevada's approach is consistent with the principles outlined in the Federal Rules of Evidence and is designed to prevent unreliable or irrelevant expert testimony from influencing the outcome of a trial.