MRE 702 provides the standard for admissibility of expert testimony. It provides: “A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the proponent demonstrates to the court that it is more likely than not that:
(a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;
(b) the testimony is based on sufficient facts or data;
(c) the testimony is the product of reliable principles and methods; and
(d) the expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.” MRE 702.
Whether a party has provided the proper foundation for admission of expert testimony is a question for the trial court. MRE 104(a). Whether a witness is qualified as an expert and whether expert testimony is admissible is a matter within the trial court’s discretion. People v Wood, 307 Mich App 485, 507 (2014).
“In determining the admissibility of scientific evidence, the court, as gatekeeper, must make a preliminary assessment of whether the testimony’s underlying reasoning or methodology is scientifically valid and properly can be applied to the facts at issue.” Daubert v Merrell Dow Pharmaceuticals, Inc, 509 US 579, 580 (1993). See also Wood, 307 Mich App at 507. Factors that a court may consider include:
•whether the scientific theory or technique can be tested and has been tested;
•whether the theory or technique has been subjected to peer review and publication;
•the known or potential error rate of the theory or technique and the existence and maintenance of standards controlling the theory or technique’s operation; and
•whether the theory or technique has attracted widespread acceptance within a relevant scientific community. Daubert, 509 US at 580; People v Kowalski, 492 Mich 106, 131 (2012).
This gatekeeper test, known as the Daubert Test, was extended to nonscientific expert testimony in Kumho Tire Co, Ltd v Carmichael, 526 US 137, 147-149 (1999). “Although the Daubert gatekeeping function applies to all experts, the list of factors in Daubert is flexible and nonexhaustive: ‘Daubert’s list of specific factors neither necessarily nor exclusively applies to all experts or in every case.’” Danhoff v Fahim, ___ Mich ___, ___ (2024), quoting Kumho Tire Co, 526 US at 141.
“A person does not have to have formal education to be an expert, but may acquire special knowledge of the subject by other means.” People v Towlen, 66 Mich App 577, 579 (1976). Moreover, “[a] witness need not possess specialized knowledge as a result of experience as well as training and eduction in order to be qualified as an expert.” Osner v Boughner, 180 Mich App 248, 261 (1989) (holding that the officer was qualified to provide expert testimony despite the fact that the accident he investigated was the officer’s first investigation). An expert also need not be a licensed professional. Mulholland v DEC Int’l Corp, 432 Mich 395, 403 (1989). While a proposed expert’s expertise may not be as extensive as the expert’s expertise on the opposing side, such consideration goes to the weight of the evidence rather than its admissibility. People v Whitfield, 425 Mich 116, 123-124 (1986). A trial court may properly consider other trial experience in determining whether a proposed expert should be allowed to testify, and the court may consider the fact that the witness has been qualified as an expert in other cases. People v Lewis, 160 Mich App 20, 28 (1987).
“[T]he guidepost for admissibility [of expert witness testimony] is reliability, and trial courts must consider MRE 702 as well as the statutory reliability factors presented in MCL 600.2955 when determining if an expert is reliable.” Danhoff, ___ Mich at ___ (holding that some conditions are so rare that there exists little to no published literature discussing them, and that the lack of published literature should not solely determine whether an expert witness’s testimony is reliable and admissible; even in the absence of supportive literature or other evidence, an expert witness’s opinion may be “otherwise sufficiently reliable under the factors provided by statute and MRE 702”). Opinions are not unreliable simply because there is no literature to support them. Id. at ___. In Danhoff, the Court held that “[t]he trial court abused its discretion by inadequately assessing [the expert witness’s] reliability as a standard-of-care expert without appropriately analyzing MRE 702 or the statutory reliability factors of MCL 600.2955.” Danhoff, ___ Mich at ___.