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 New Mexico, as in many jurisdictions, the admissibility of expert witness testimony is governed by rules that require the expert to have specialized knowledge, skill, experience, training, or education that is pertinent to the case at hand. The expert's testimony should provide assistance to the judge or jury in understanding the evidence or in making a determination on a contested fact. The judge serves as a gatekeeper, ensuring that the expert's testimony is not only relevant but also reliable. There is no strict formula for qualifying an expert; instead, the judge must evaluate whether there is an appropriate match between the expert's qualifications and the subject matter of the dispute. This evaluation is based on the relevance of the expert's specific expertise to the issues in the case and the applicability of their methodology. The New Mexico Rules of Evidence, particularly Rule 11-702, guide these determinations, reflecting a flexible approach that allows the court to exercise discretion in admitting expert testimony.