Standards for Engineer Witnesses

The article about the Supreme Court's pending case involving standards for expert witnesses, “Should engineer witnesses meet same standards as scientists?” by Jocelyn Kaiser (News of the Week, 11 Sept., p. [1578][1]), suggests that the issue in that case, Kumho Tire Co. v . Carmichael , is whether the standards for admitting scientific expert witness testimony that the Court set forth in Daubert v. Merrill Dow Pharmaceuticals, Inc. ([1][2]) are applicable to engineering experts. ![Figure][3] CREDIT: ANNE ELLIOT CUTTING While the expert witness in the Kumho case was an engineer, he eschewed reliance on any engineering methods in forming his opinion. Rather, the expert, who had worked in the tire industry, relied on his experience in examining and analyzing tires that had failed. As the lower court in Kumho observed ([2][4]): > [The expert] makes no pretense of basing his opinion on any scientific theory of physics or chemistry. Instead [he] rests his opinion on his experience in analyzing tires. After years of looking at the mangled carcasses of blow-out tires, [the expert] claims that he can identify telltale markings revealing whether a tire failed because of abuse or defect…. [The expert] maintains that his experiences in analyzing tires have taught him what “bead grooves” and “sidewalk deterioration” indicate as to the cause of a tire's failure. Thus, the Kumho case presents the question of whether a witness claiming expertise based on experience is to be evaluated by the criteria set forth in Daubert. Kumho does not address the question of whether a witness, relying on engineering principles, who testifies to an opinion, say, about how an automobile accident occurred, should be screened on the basis of the dictates of Daubert . The challenge in Kumho will be whether the Supreme Court can identify certain areas of human endeavor in which valuable understanding is obtained through experience. This experience provides knowledge through a process quite different from rigorous empirical scientific investigation, but may nevertheless be of value in court, because it involves phenomena that scientists do not study because of cost, lack of interest, or their mundane nature. If the experience provides greater accuracy than we might otherwise obtain, it may, although unscientific, still be of considerable legal value. 1. [↵][5]13 S. Ct. 2786(1989). 2. [↵][6] Carmichaelv. Samyang Tire, Inc ., 131 F. 3d 1433 (11th Cir., 1997). # {#article-title-2} Kaiser's News article features the brief filed by the National Academy of Engineering (NAE) in support of the Kumho Tire Co. in Kumho v. Carmichael . Although I agree with the NAE's position regarding this particular expert's testimony, extending the criteria enunciated in Daubert v. Merrill Dow Pharmaceuticals, Inc. to all engineering expert testimony would be a serious mistake. Engineering, like medicine, is based on science, but both fields transcend science. In products liability cases, such as Kumho , one must determine whether a defect caused the failure that resulted in injury, loss of life, or damage to property. Although Daubert criteria work reasonably well for manufacturing defects, they are inadequate for design defects. In design defect cases, judgment and experience, as well as science, determine feasibility, factors of safety, acceptable failure rates, and appropriate computer simulations. Daubert provides little guidance. Reliance on experience and judgment in decisions that affect lives of others sets engineering and medicine apart from science. For this reason engineers and physicians are licensed to practice their professions, while scientists require no such license to practice their science. Historically, physicians, and later engineers, were licensed by the state to protect the public by limiting certain activities (such as cutting into people and designing and manufacturing pressure vessels) to holders of those licenses. In return for the state's granting licenses, the profession certifies qualified individuals and requires them to hold certain values paramount. For engineers, these values are life, health, welfare, and property of the public. Perhaps the Supreme Court will restrict engineering and medical testimony to licensed engineers and physicians, while anyone with a scientific education (including engineers and physicians) can testify about science, subject to Daubert criteria for that part of their testimony. # {#article-title-3} Kaiser does not point out the vital point that the Supreme Court made in the Daubert v. Merrill Dow Pharmaceutical, Inc. : “in order to qualify as ‘scientific knowledge’ an inference or assertion must be derived by the scientific method.” The scientific method is a general method applicable to all fields that seek reliable knowledge. Thus, all expert witnesses should be obligated to show that they have used the scientific method in arriving at the conclusions they provide in their testimony and assertions. [1]: /lookup/doi/10.1126/science.281.5383.1578a [2]: #ref-1 [3]: pending:yes [4]: #ref-2 [5]: #xref-ref-1-1 "View reference 1 in text" [6]: #xref-ref-2-1 "View reference 2 in text"