Admissibility versus Sufficiency: Controlling the Quality of Expert Witness Testimony in the United States

44 Pages Posted: 6 Mar 2012 Last revised: 23 Jan 2014

See all articles by Michael D. Green

Michael D. Green

Wake Forest University - School of Law

Joseph Sanders

University of Houston Law Center

Date Written: March 5, 2012


Daubert v. Merrell Dow Pharmaceuticals, established a new method of assessing the admissibility of expert testimony in federal courts. The opinion and two subsequent opinions,General Electric v. Joiner and Kumho Tire v. Carmichael, have had a profound impact on civil litigation in the United States. Parties now routinely challenge the admissibility of the opposing expert’s testimony. This has lead to the exclusion of experts in hundreds, perhaps thousands of cases. Given this substantial impact, it is perhaps surprising that considerable confusion still persists concerning exactly how trial courts should think about the decision to admit or exclude expert testimony. In this paper, we argue that much of the confusion exists because of the four factors provided in Daubert for assessing the reliability of an expert’s methodology. Reading lower court cases that address admissibility reveals that those factors are largely unhelpful in resolving the admissibility question. Rather than conceiving of the issue as one involving admissibility, we argue that the best way to clarify the Daubert inquiry is to appreciate that most admissibility decisions are best thought of as sufficiency judgements. By that, we mean that the court should consider the scientific evidence proffered by the expert and engage in what courts have long done–assess the sufficiency of that evidence to permit the fact finder to reasonably infer causation (or whatever other issue the expert’s opinion addresses). Courts have, since the advent of juries, made the determination of whether a party’s evidence is sufficient for an inference or would, on the other hand, only leave the jury to impermissible speculation about the issue in dispute. We not only believe this is a better approach, we also believe that a close reading of opinions indicates that in fact many courts do adopt a sufficiency approach when making Daubert admissibility rulings.

Suggested Citation

Green, Michael D. and Sanders, Joseph, Admissibility versus Sufficiency: Controlling the Quality of Expert Witness Testimony in the United States (March 5, 2012). Wake Forest Univ. Legal Studies Paper No. 2016468, U of Houston Law Center Paper No. 2016468, Available at SSRN: or

Michael D. Green (Contact Author)

Wake Forest University - School of Law ( email )

P.O. Box 7206
Winston-Salem, NC 27109
United States

Joseph Sanders

University of Houston Law Center ( email )

4604 Calhoun Road
Houston, TX 77204-6060
United States
713-743-2125 (Phone)
713-743-2299 (Fax)

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