Source: https://cyber.harvard.edu/daubert/ca.htm
Timestamp: 2019-04-18 15:35:59+00:00

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Expert witnesses have become fixtures in today's courts. From fiber comparisons to economic projections to psychiatric evaluations, the range of offered expertise covers the span of human knowledge. Hardly a case of any consequence goes to trial without expert testimony of some kind. With such widespread use of expert testimony comes the inevitable question: "what is the trial judge's role in overseeing the testimony of expert witnesses?" Unlike lay witnesses, whose testimony a jury can evaluate based on their own common sense and experience, expert witnesses offer conclusions based on practices and knowledge beyond the ken of the average juror. As a consequence, testimony by unpoliced expert witnesses can have a potentially prejudicial effect on jurors, who may be inclined to believe the experts solely because of their "expert status." How is the trial judge to know whether the expert is merely speculating, or whether the evidence on which the expert bases his or her conclusions is sufficient to support the conclusion? Judges certainly prevent lay witnesses from speculating and are expected to exclude the testimony of a witness offering wholly speculative evidence. Why should this mandate be any different when the witness purports to be an expert?
If one accepts the proposition that the trial judge has a duty to exclude unreliable experts, a host of concerns inevitably follows. How is a trial judge to assess the scientific or technical adequacy of expert testimony if even a cursory understanding of the issues requires specialized training? Can anyone without such training fully understand the issues and come to a rational conclusion as to their validity? To what degree can the trial judge rely on the expert's own assertions about his or her qualifications? All of these concerns carry heavy weight for in many cases the trial judge is hardly a more qualified assessor of scientific credibility than the jury itself. In this introduction and the papers which follow it, we have laid out some possible answers to the myriad questions raised by judicial gatekeeping. This first paper attempts to establish a historical perspective on gatekeeping in California. The papers which follow it give a more generalized picture of the gatekeeping debate. Ultimately we hope that you find these materials helpful in formulating or fine tuning your own approach to science in the courts.
In 1923, the D.C. Circuit announced its landmark decision regarding the admissibility of expert opinion testimony on novel scientific procedures in Frye v. United States.(1) In Frye, the defendant attempted to show his innocence by proffering the results of a lie detector test that purportedly demonstrated that he was telling the truth when he denied killing the victim. The court ruled that the evidence was inadmissible because the scientific principles upon which the procedure was based were not, "sufficiently established to have gained general acceptance in the particular field in which it belongs."(2) This so-called Frye general acceptance test remained the standard employed in both federal courts and state courts around the country for years to come.
With the adoption of the Federal Rules of Evidence in 1975, courts, scholars and practitioners alike began to question whether Fryewould survive as the sole admissibility standard for expert testimony. Under the Federal Rules, judges were seemingly afforded more discretion in making admissibility determinations. Rule 104(a) assigns judges the responsibility of making a preliminary determination on whether to allow a given expert to testify. Rule 702 goes on to guide this decision by requiring the judge to determine whether the admission of such testimony will assist the trier of fact to understand evidence or determine a fact at issue. Finally, Rule 403 suggests that the judge may exclude evidence if its likely prejudicial effect outweighs its probative value. The question was then to what degree would the arguably conservative Frye general acceptance standard survive in the wake of the presumably more liberal admissibility framework embodied in the new Federal Rules of Evidence.
Logistically, Kelly / Frye requires "a preliminary showing of general acceptance of the new technique in the relevant scientific community."(10) From there, California Evidence Code §§ 720 & 801 take over and require a two step process: "(1) the Reliability of the method must be established, usually by expert testimony, and (2) the witness furnishing such testimony must be properly Qualified as an expert to give an opinion on the subject."(11) This system of admitting scientific evidence has remained virtually unchanged in California, and most notably, survived the United States Supreme Court Daubert decision.
In People v. Leahy,(12) the Supreme Court of California reaffirmed its allegiance to the Kelly / Frye, standard and fully rejected Daubert. The Leahy Court began its analysis by noting the similarities between the 1965 California Evidence Code and the Federal Rules of Evidence upon which Daubert was based. The Court first reminded the reader of the similarity between the relevance standards of California sections 350(13) and 351(14) and Federal Rules of Evidence 401(15) and 402.(16) Next, the Court explained that sections 720(17) and 801(18) taken together were the "functional equivalent of Federal Rules of Evidence, rule 702."(19) Interestingly, the Leahy Court stressed that the two state sections did not expressly establish "general acceptance as an absolute prerequisite to admissibility, and nothing in the legislative history leading to adoption of the Evidence Code indicates that a general acceptance standard was intended."(20) General acceptance then, is clearly a product of the common law.
The circuit court's "particularly stringent," pro-admission standard was indeed short lived.
Upholding a judge's right to exclude given expert testimony on the basis of perceived analytical gaps in the science is an unprecedented broadening of the gatekeeper role. Such a ruling at first seems to run contrary to the "liberal thrust" of the Rules of Evidence as articulated in Daubert. It remains to be seen whether courts will be as deferential when judges exercise their discretion in favor of admissibility of arguably questionable scientific evidence. Whether Joiner will effect California and states like her that have not adopted Daubert also remains to be seen.
1. 293 F. 1013 (D.C. Cir. 1923).
3. 113 S. Ct. 2786 (1993).
5. See id. at 2796-7.
6. See, e.g., People v. Jones, 343 P.2d 577 (Cal. 1959) (truthserum); People v. Carter, 312 P.2d 665 (Cal. 1957) (lie detector test); People v. Spigno, 319 P.2d 458 (Cal. 1957) (polygraph tests).
7. 549 P.2d 1240 (Cal. 1976).
12. 882 P.2d 321 (Cal. 1994).
24. Id. at 325 citing Kelly, 549 P.2d at 1240.
25. See id. at 330.
26. See id. at 331.
27. See id. at 330.
28. See, e.g., People v. Venegas, 954 P.2d 525 (Cal. 1998).
29. 118 S. Ct. 512 (1997).
30. See id. at 516.
33. See id. citing General Electric Co. v. Joiner, 865 F. Supp., 1310, 1326 (N.D. Ga. 1994).
34. General Electric Co. v. Joiner, 78 F.3d 524, 529 (11th Cir. 1996) (emphasis added).
35. Joiner, 118 S. Ct. at 517 (citations omitted)..
36. Id. at 518 (citations omitted).

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