Judging Expert Testimony: From Verbal Formalism to Practical Advice


  • Susan Haack University of Miami



Appraising the worth of others’ testimony is always complex; appraising the worth of expert testimony is even harder; appraising the worth of expert testimony in a legal context is harder yet. Legal efforts to assess the reliability of expert testimony—I’ll focus on evolving U.S. law governing the admissibility of such testimony—seem far from adequate, offering little effective practical guidance. My purpose in this paper is to think through what might be done to offer courts more real, operational help. The first step is to explain why the legal formulae that have evolved over the years may seem reassuring, but aren’t really of much practical use. The next is to suggest that we might do better not by amending evidentiary rules but by helping judges and attorneys understand what questions they should ask about expert evidence. I focus here on (i) epidemiological testimony, and (ii) the process of peer review.

Palabras clave

evidence law, expert testimony, reliability, epidemiology, peer review, the Daubert-Joiner-Kumbo régime


Armstrong, D., 2006, May 15: «How the New England Journal missed warning signs on Vioxx: Medical weekly waited years to report flaws in article that praised drug», in Wall Street Journal: https://www.wsj.com/articles/SB114765430315252591

Beecher-Monas, E., 2009: «Reality bites: The illusion of science in bite-mark evidence», in Cardozo Law Review, 30 (4): 1369-1410.

Capon, R., 2016: «The performance of the Italian civil justice system: An empirical assessment», in Italian Law Journal, 2 (1): 15-31.

Clifford, W.K., 1947: «The ethics of belief» (1877), in The ethics of belief and other essays (eds. Stephen, L., & Pollock, F). London: Watts & Co., 70-96.

Federal Judicial Center, 1994: Reference manual on scientific evidence. Washington, D.C.

— 2000: Reference manual on scientific evidence. Washington, D.C.

— 2011: Reference manual on scientific evidence. Washington, D.C.

Friedman, L. M., 2010: «Expert testimony, its abuse and reformation», in Yale Law Journal, 19 (4): 247-257.

Haack, S., 2005: «Trial and error: The Supreme Court’s philosophy of science», in American Journal of Public Health, 95 (Supplement 1): S66-73. Reprinted as «Trial and error: Two confusions in Daubert» in Haack, 2014a: 104-21.

— 2007: «Peer review and publication: Lessons for lawyers», in Stetson Law Review, 36 (3): 789-819. Reprinted in Haack, 2014a: 156-79.

— 2008: «What’s wrong with litigation-driven science? An essay in legal epistemology», in Seton Hall Law Review, 38 (3): 1053-83. Reprinted as «What’s wrong with litigation-driven science? » in Haack, 2014a: 180-207.

— 2010:«Federal philosophy of science: A deconstruction—and a reconstruction», in NYU Journal of Law and Liberty, 5 (2): 394-435. Reprinted in Haack, 2014a: 122-55.

— 2014a: «Credulity and circumspection: Epistemological character and the ethics of belief», in Proceedings of the American Catholic Philosophical Association, 88: 27-47, available at https://www.pdcnet.org/acpaproc/content/acpaproc_2015_0999_11_16_25.

— 2014b: «Correlation and causation: The “Bradford Hill Criteria” in epidemiological, legal, and epistemological perspective», in Haack, 2014a: 239-63.

— 2014c: Evidence matters: Science, truth, and proof in the law. New York: Cambridge University Press.

— 2016: «Mind the analytical gap! Tracing a fault line in Daubert», in Wayne Law Review, 61 (3): 653-90.

— 2018: «In the epistemological spotlight: Epidemiological evidence in toxic torts», in Memoria XV Congreso Panameño de Derecho Procesal: 361-78.

Hal, N., 2016, September 1: «Fla. high court weighs changes to expert witness standard», in Law360: https://www.law360.com/articles/790136/fla-high-court-weighs-changes-to-expert-witness-standard.

Haug, C., 2015, December 17: «Peer-Review fraud—hacking the scientific publication process», in New England Journal of Medicine, 373 (25): 2393-95.

Henneckens, C. H., et al., 1996: «Self-Reported breast implants and connective tissue diseases in female health professionals: A retrospective cohort study», in Journal of the American Medical Association, 275 (8): 616–21.

Hill, A.B., 1965: «The environment and disease: Association or causation? », in Proceedings of the Royal Society of Medicine, 58 (5): 295-300.

Himes, C. F., 1893, « The scientific expert in forensic procedure», in Journal of the Franklin Institute, 135 (6): 407-436.

McGinty, J. C., 2018, May 5: «Shifting standards cloud autism’s progress», in Wall Street Journal: https://www.wsj.com/articles/on-autism-shifting-u-s-standards-cloud-the-number-of-cases-1525446011.

National Research Council, 2009: Strengthening the forensic sciences in the United States. Washington, D.C.: National Academic Press.

Wakefield, A., et al., 1998, February 19: «Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children», in The Lancet, 351 (9103): 637-41.

Cases and Statutes Cited
2013 Fla. Laws 107 (codified as Fla. Stat. § 90.702 (2018)). Barefoot v. Estelle, 463 U.S. 880 (1983). Berry v. City of Detroit, 25 F.3d 1342 (6th Cir. 1994). Blum v. Merrell Dow Pharm., Inc., 33 Phila. Cnty. Rep. 193 (1996). Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993). Daubert v. Merrell Dow Pharm., Inc., 43 F.3d 1311 (9th Cir. 1995). Delisle v. Crane Co., 258 So. 3d 1219 (2018). Ferguson v. Hubbell, 97 N.Y. 507, 514 (1884). Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). Gen. Elec. Co. v. Joiner, 522 U.S. 136 (1997). In re: Amendments to the Florida Evidence Code, No.SC19-107 (Fla. May 23, 2019). Kaminski v. State, 63 So.2d 339 (1952). Kumho Tire v. Carmichael, 526 U.S. 137 (1999). Manko v. United States, 636 F. Supp. 1419 (W.D. Mo. 1986). N.Y. & Erie R.R. Co., 62 U.S. 88, 101 (1858). Ramirez v. State, 810 So. 2d 836 (Fla. 2001). United States v. Bonds, 12 F.3d 540 (6th Cir. 1993).

Biografía del autor/a

Susan Haack, University of Miami

Distinguished Professor in the Humanities, Cooper Senior Scholar in Arts and Sciences, Professor of Philosophy and Professor of Law at the University of Miami.





Cómo citar

Haack, S. (2020). Judging Expert Testimony: From Verbal Formalism to Practical Advice. Quaestio Facti. Revista Internacional Sobre Razonamiento Probatorio, (1), 13–30. https://doi.org/10.33115/udg_bib/qf.i0.22312