§ 18:3. ADMISSIBILITY OF EXPERT TESTIMONY
In recent times, concern has been expressed over the admission of “junk science” into the courts, with its seriously distorting effect on juries. The expert witnesses offered usually have credentials generally accepted by the courts to qualify the witness to express expert opinions. Although the unsoundness of their seemingly impressive evidence can be adequately countered in a case before a judge by a party with the very large resources needed to provide, present and explain the relevant and available studies,14 it cannot be met adequately in most jury cases without additional controls on admissibility.
In the case of Daubert v. Merrill Dow Pharmaceuticals,15 the United States Supreme Court, in interpreting Federal Rule of Evidence 702, changed the legal standard for determining the reliability of expert opinion evidence which had been in place for 100 years,16 and which had been used in Delaware (albeit not exclusively).17 Previously, expert evidence was deemed reliable if the basis for the opinion was “generally accepted” in the community of experts in the relevant field. In Daubert, the United States Supreme Court held that the test is now “whether the reasoning or methodology underlying the testimony is scientifically valid and…whether the reasoning and methodology properly can be applied to the facts in issue.”18 The United States Supreme Court identified several non-exclusive factors that trial courts should consider, including testing, peer review, error rates and acceptability in the relevant scientific community.19 In Kumho Tire Co., Ltd. v Carmichael, the U.S. Supreme Court extended Daubert beyond scientific expert opinion to include technical or other specialized knowledge,20 and Delaware has followed that rule.21
The Delaware Supreme Court has held that the methodology established in Daubert is the correct method to be applied under Delaware Rule of Evidence 702.22
The trial judge is considered the “gatekeeper,” and is required to determine the admissibility of expert evidence.23. In making that determination, trial courts are to decide whether (1) the witness is qualified as an expert by virtue of knowledge, training, education, skill and experience, (2) the evidence is relevant and reliable (incorporating the Daubert test), (3) the expert’s opinion is based on information reasonably relied upon by experts in the particular field, (4) the expert testimony will assist the trier of fact to understand the evidence in determining a fact in issue, and (5) the expert testimony will not create unfair prejudice or confuse or mislead the jury. This list is non-exhaustive. The party proffering the expert witness has the burden of meeting these criteria by a preponderance of the evidence.24
For scientific evidence to be deemed reliable, the testimony must be supported by scientific knowledge and derive from the scientific method. If there is a challenge to the data, principles or methodology underlying an opinion, the trial judge must determine whether the testimony is supported by the knowledge and experience of the relevant discipline. To make that determination, the judge must consider whether the information (i) has been or can be tested, (ii) has been subjected to peer review or publication, (iii) is a result of a technique with a known or potential rate of error, and what that rate of error is, and (iv) is generally accepted within the scientific community. This is not a definitive checklist, however.24.1 The test of reliability is flexible, and it is within the discretion and responsibility of the Court to devise how to measure reliability as well as to perform the measurement given the specifics and disciplines involved in the given case before it.24.2
Delaware courts generally recognize that challenges to the factual basis of an expert opinion go to the credibility, and not the admissibility, of the expert testimony, and it is for the opposing party to test on cross-examination. An expert’s testimony will be excluded on the ground of factual basis only in the narrow circumstance where the expert has completely neglected the core facts of the case.24.2
The trial judge has broad latitude to determine whether the proffered expert testimony is sufficiently reliable and relevant.25 Expert testimony is relevant if it assists the fact finder in understanding the evidence or determining a fact in issue. Expert testimony is reliable when it is grounded in reliable methods and procedures and supported by appropriate validation. At bottom, the Court’s examination of an expert’s opinion must be focused solely on principles and methodology, and not the conclusions they generate.25.1
The trial judge also has broad latitude to determine whether any or all of the Daubert factors are reasonable measures of reliability in a given case.26 Other factors, such as the source of funding of scientific research relied upon by an expert, may be considered.27
In a non-jury case, the judge may be more flexible in application of Daubert, on the theory that a judge is better suited to consider any shortcomings in the expert testimony that may be brought out on cross examination.28
A party seeking to challenge expert testimony must do so in a timely fashion. Failure to do so may be deemed waiver of any objections on Daubert grounds to the testimony of the expert.29
A full evidentiary hearing is not required to establish the admissibility of expert testimony. Absent special circumstances, it is sufficient for the court to rely on deposition testimony and affidavits.30 In the Court of Chancery, as there is no jury, the practice is not to engage in pre-trial Daubert hearings, but to allow the evidence to come in, subject to post trial briefing on its admissibility.30.1
The general rule has been that an expert reports are generally inadmissible as evidence on the ground that they contain hearsay.30.2 That rule is not without exceptions, however. In at least one non-jury case, the Court of Chancery found that, under the circumstances of that case, expert reports were admissible under an exception to the hearsay rule where admitting the hearsay “will best serve the purposes of these Rules and the interests of justice”30.3, where (i) the expert reports were exchanged sufficiently in advance of trial to allow counsel to digest them fully, (ii) the experts had been thoroughly deposed, (iii) the experts would be subject to cross-examination at trial, (iv) the experts addressed matters of material importance on matters uniquely susceptible to expert proof, (v) all parties had been given advance notice that the reports may be offered as evidence at trial, and (vi) the judge was certain that he would find the reports of use as he deliberated the evidence and reached his verdict in an expedited trial.30.4
14. See Johnston v. United States, 597 F. Supp. 374, 409, 415 (D. Kan. 1984).
15. Daubert v. Merrill Dow Pharmaceuticals, 509 U.S. 579 (1993).
16. Frye v. United States, 293 F. 1013 (D.C. App. 1923).
17. Fensterer v. State, 493 A.2d 959, 962 n.3 (Del.), rev’d on other grounds, 474 U.S. 15 (1985); Whalen v. State, 434 A.2d 1346, 1354 (Del. 1981). See also Minner v. Am. Mortgage & Guar. Co., 791 A.2d 826, 830 (Del. Super. 2000) (“[t]he Frye approach was never fully accepted nor rejected by the Delaware Courts”) (citing treatise).
18. Daubert v. Merrill Dow Pharmaceuticals, 509 U.S. 579, 592-93 (1993).
19. Daubert v. Merrill Dow Pharmaceuticals, 509 U.S. 579, 593-94 (1993).
20. Kumho Tire Co., Ltd. v Carmichael, 526 U.S. 137 (1999).
21. Farrell v. University of Delaware, C.A. No. 07C-09-175 PLA, Ableman, J. (Del. Super. Nov. 24, 2009).
22. Perry v. Berkley, 996 A.2d. 1262, 1267 (Del. 2010); Bowen v. E.I. du Pont de Nemours & Co., Inc., 906 A.2d 787, 794 (Del. 2006); Ward v. Shoney’s, Inc., 817 A.2d 799 (Del. 2003); Price v. Blood Bank of Delaware, Inc., 790 A.2d 1203, 1210 (Del. 2002); Bell Sports, Inc. v. Yarusso, 759 A.2d 582, 588 (Del. 2000).
23. Perry v. Berkley, 996 A.2d. 1262, 1267 (Del. 2010); General Motors Corp. v. Grenier, 981 A.2d 531, 536 (Del. 2009); McNally v. State, 980 A.2d 364, 368 (Del. 2009); Sturgis v. Bayside Health Ass’n Chartered, 942 A.2d 579, 584 (Del. 2007); Bowen v. E.I. du Pont de Nemours & Co., Inc., 906 A.2d 787, 795 (Del. 2006).
24. Tumlinson v. Advanced Micro Devices, Inc., 81 A.3d 1264, 1268, 1271 (Del. 2013); Sturgis v. Bayside Health Ass’n Chartered, 942 A.2d 579, 584 (Del. 2007); Spencer v. Wal-Mart Stores East, LP, 930 A.2d 881, 888 (Del. 2007); Bowen v. E.I. du Pont de Nemours & Co., Inc., 906 A.2d 787, 795 (Del. 2006); Tolson v. State, 900 A.2d 639, 645 (Del. 2006); Eskin v. Carder, 842 A.2de 1222, 1227 (Del. 2004).
24.1. Laugelle v. Bell Helicopter Textron, Inc., C.A. No. N10C-12-054 PRW, slip op. at 4, Wallace, J. (Oct. 6, 2014); Brown v. United Water Delaware, Inc., C.A. No. 07C-07-070-JAP, slip op. at 4-5, Parkins, J. (Del. Super. Oct. 7, 2011).
24.2. Henlopen Hotels, Inc. v. United National Insurance Company, C.A. No. N18C-09-212 PRW, slip op. at 3, Wallace, J. (Del. Super. Jan. 15, 2020).
24.3. State v. Dale, ID No. 1909010294, slip op. at 15-16, Wallace, J. (Del. Super. Nov. 10, 2021).
25. Perry v. Berkley, 996 A.2d. 1262, 1267 (Del. 2010).
25.1. Henlopen Hotels, Inc. v. United National Insurance Company, C.A. No. N18C-09-212 PRW, slip op. at 6, Wallace, J. (Del. Super. Jan. 15, 2020).
26. General Motors Corp. v. Grenier, 981 A.2d 531, 536 (Del. 2009).
27. General Motors Corp. v. Grenier, 981 A.2d 531, 540 (Del. 2009).
28. Beard Research, Inc. v. Kane, C.A. No. 1316-VCP, slip op. at 30, Parsons, V.C. (April 23, 2010).
29. Beard Research, Inc. v. Kane, C.A. No. 1316-VCP, slip op. at 29, Parsons, V.C. (April 23, 2010) (failure to raise issue in pretrial proceedings or during trial constitutes a waiver).
30. Minner v. Am. Mortgage & Guar. Co., 791 A.2d 826, 834-36 (Del. Super. 2000); Jones v. Astrazeneca, LP, C.A. No. 07C-01-420 SER, slip op. at 20, Slights, J. (Del. Super. Mar. 31, 2010).
30.1. Preferred Investment Services, Inc. v. T&H Bail Bonds, Inc., C.A. No. 5886-VCP (Del. Ch. Sept. 14, 2012) (transcript).
30.2. Bangs v. Follin, C.A. No. k15C-05-008 JJC, slip op. at 5, Clark, J. (Del. Super. Jan. 13, 2017); Gerstley v. Mayer, C.A. No. N12C-10-126 EMD, slip op. at 18 n.48 (Del. Super. Feb. 11, 2015).
30.3. D.R.E. 807(a)(4).
30.4. In re Comtech/Gilat Merger Litigation, C.A. No. 2020-0605 (JRS), slip op. at 3-7 (Del. Ch. Oct. 2, 2020).
© 2022 David L. Finger