Sometimes a defendant wants to have multiple experts at trial. I oppose this practice. Repetitive and cumulative expert testimony is not helpful to a jury - it is unduly prejudicial to call redundant experts at trial to get a numbers advantage. But what's Missouri law say? A circuit court may allow an expert to testify if “scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue…” RSMo. § 490.065. In Shallow v. Follwell, 554 S.W.3d 878 (Mo. banc 2018), the Missouri Supreme Court approved a defendant calling four experts at a medical malpractice trial:1) a doctor in general surgery and critical care medicine to testify about the standard of care; 2) a cardiologist to testify solely in response to plaintiff’s expert; 3) a vascular surgeon, and 4) a colorectal surgeon. Id. at 884. The Court held the circuit court did not abuse its discretion by admitting the testimony, reasoning, “each one of the experts [has] a different specialty and they all added their own parts.” Id. at 884. One might argue it was only allowed because all were different specialties. But the Court said: [The] experts testified about the very root of the matter in controversy; the evidence therefore, was not cumulative. While the expert testimony overlapped at times, the experts testified about their own specialties and offered their own parts.... [T]he overlapping testimony went to the issue of the standard of care and causation—the “very root” of a wrongful death action arising from medical negligence. For this reason, the expert testimony was not cumulative under Missouri law. Further, “Even if evidence is cumulative, that alone is not sufficient to exclude its admission.” Well then is nothing cumulative? Maybe not, because the court then said: This does not mean the number of experts who may testify about the very root of the controversy on behalf of a party is limitless and always legally relevant. The probative value of logically relevant collective evidence going to the very root of the controversy must also ‘be weighed against the risks it poses of unfair prejudice.’ If the prejudicial effect substantially outweighs the probative value, the evidence is unfairly prejudicial, not legally relevant, and must be excluded. Excessive expert witnesses can create the risk the trier of fact will resolve differences in expert witness opinions by the number of experts called instead of giving due consideration to the quality and credibility of each expert opinion. While expert witnesses testifying about the very root of the controversy have purpose and are not needlessly repetitive, such evidence remains subject to exclusion if the prejudicial effect of the testimony substantially outweighs the probative value. Shallow v. Follwell, 554 S.W.3d at 885. So, what's the answer? (drum roll please) Come to our CLE to find out (Ha).