According to the Daubert standard the court requires independent judicial assessment of the reliability of expert witness testimony, which has to be based on a scientific technique and general acceptance in the scientific community.
Prior to the Daubert standard, the Frye standard, or general acceptance test, was in common use to determine the general admissibility of scientific evidence in United States Federal courts. According to the Frye standard, expert opinion based on scientific technique was admissible only when the technique could be proved to be generally accepted as reliable in the specific scientific community.
The Frye standard was rejected in Daubert v. Dow (1993) and the court finding required independent judicial assessment of reliability of expert witness testimony based on a scientific technique. Subsequently the Daubert standard superseded the Frye standard in 10 US states, while Frye remains the standard in 14 states and the remaining states substituted Frye with their own standards, mostly a “balanced test approach, consistent with Daubert” (State v. Goode, 1995, p. 1).
Providing empirically based evidence in court is important to ensure that experts present relevant opinions grounded in reliable methodology, resulting in a fair and rational resolution of scientific and technological issues presented in court, thereby setting higher barriers for expert testimony.
Two subsequent cases that applied and interpreted the Daubert standard were General Electric Company v. Joiner (1997) and Kumho Tire Company v. Carmichael (1999). In Electric Company v. Joiner (1997) the court held that the experts’ testimony for the plaintiff had failed to sufficiently prove the link between exposure to the chemicals in question and lung cancer and was therefore inadmissible because it did not rise above “subjective belief or unsupported speculation” (p. 1). In Kumho Tire v. Carmichael (1999) expert testimony from non-scientists were considered under the Daubert standard and the court conceded that the line between scientific and technical knowledge were not always clear. The tire failure expert’s testimony was based on tactile and visual inspection of a blown tire and Kumho Tire Company moved to exclude the testimony under the Daubert standard as non-scientific. The court granted the motion and acknowledged its role as gatekeeper of the Daubert standard by finding that the evidence did not fulfill the requirements thereof.
Specifically, the Daubert standard required experts to prove falsifiability of evidence or results, peer review and publication of the issue at hand, known or potential error rate of results, declaration of the standards of control in the application of the specific technique, and general acceptance in the scientific community.
The Daubert standard was amended in 2000 by Rule 702 (Giannelli, 2000), which specified that the testimony must be based on sufficient facts or data, is a product of reliable principles and methods, and finally, that the expert witness has applied the principles and methods reliably to the fact of the case. In addition, the witness must be appropriately qualified in the subject matter and the topic must be a proper subject for expert testimony.
Specific examples relating to forensic psychology that failed the Daubert test, for the most part, include eyewitness identification, hypnosis, polygraph evidence, battered woman syndrome, criminal profiling and crime classification. Similarly, psychiatric and other psychological evidence has had mixed results under Daubert. Techniques such as psychological or sociopsychological profiling were also found to lack logical foundation and weak methodology.
In conclusion, court application of the Daubert standard has a definite influence on how scientific evidence is handled in practice and research (Cheng & Yoon, 2005) and continued efforts are required in the field of forensic psychology to overcome reliability issues, bias, incompetence and scientific validity shortcomings in order to provide grounded and acceptable support in the courtroom (Neufeld, 2005).
Cheng, E.K. & Yoon, A.H. (2005). Does Frye or Daubert matter: A study of scientific admissibility standards. Virginia Law Review, 91(2), 471-513.
Daubert v. Merrell Dow Chemicals Inc. (1993). 509, U.S. 579, 589.
General Electric Company v. Joiner. (1997). 522, U.S. 136.
Giannelli, P. (1986). Scientific evidence. Western Reserve University. Retrieved on June 12, 2010 from http://www.goextranet.net/Seminars/Ohio06/Tab%2002-Scientific%20Evidence-Gianelli/Judicature%20-%20Scientific%20Evidence.pdf.
Kumho Tire Company v. Carmichael. (1999). 526, U.S. 137.
Neufeld, P.J. (2005). The (near) irrelevance of Daubert to criminal justice and some suggestions for reform. American Journal of Public Health, 95(S1), 107-113. doi:10.2105/AJPH.2004.056333
State v. Goode. (1995). 341 N.C. 513, 461 S.E. 2d 631.