Preponderance of Evidence California Case Law

The California Supreme Court has stated, "under the Kelly rule (People v. Kelly (1976) 17 Cal.3d 24) the proponent of evidence derived from a new scientific methodology must satisfy three prongs, by showing, first, that the reliability of the new technique has gained general acceptance in the relevant scientific community, second, that the expert testifying to that effect is qualified to do so, and, third, that ' "correct scientific procedures were used in the particular case." ' " (People v. Roybal (1998) 19 Cal.4th 481, 505 (Roybal).) The party offering the evidence has the burden of proving its admissibility by a preponderance of the evidence. (People v. Ashmus (1991) 54 Cal.3d 932, 970 (Ashmus); disapproved on another point in People v. Yeoman (2003) 31 Cal.4th 93, 117.) Under Kelly, "reliability" means the new technique " 'must be sufficiently established to have gained general acceptance in the particular field in which it belongs.' " (Kelly, supra, 17 Cal.3d at p. 30.) However, general acceptance does not require absolute unanimity of views, but rather a consensus of the relevant, qualified scientific community. (People v. Leahy (1994) 8 Cal.4th 587 at p. 612.) In resolving this matter, "the goal is not to decide the actual reliability of the new technique, but simply to determine whether the technique is generally accepted in the relevant scientific community." (People v. Barney (1992) 8 Cal.App.4th 798, 810, distinguished on another point in People v. Soto (1999) 21 Cal.4th 512, 538.) To do so, the trial court considers the quality, as well as the quantity, of the evidence supporting or opposing the new technique and, in doing so, may consider published appellate decisions and scientific literature relating to the matter. (Leahy, supra, at pp. 611-612; Kelly, supra, at p. 32.) Further, "when, as in DNA testing, the reliability of the technique employed is not readily apparent to lay observation or experience, Kelly-Frye requires determination 'whether a laboratory has adopted correct, scientifically accepted procedures' for conducting the test. 'Consideration and affirmative resolution of these questions constitutes a prerequisite to admissibility under the third prong of Kelly.' " (Roybal, supra, 19 Cal.4th at p. 505.) Thus the third prong is not merely a question of evidentiary weight, but an element of the initial admissibility determination. (See People v. Axell (1991) 235 Cal.App.3d 836, 862.) Such prong involves "further scrutiny of a methodology or technique that has already passed muster under the central first prong of the Kelly test, in that general acceptance of its validity by the relevant scientific community has been established. The issue of the inquiry is whether the procedures utilized in the case at hand complied with that technique. Proof of that compliance does not necessitate expert testimony anew from a member of the relevant scientific community directed at evaluating the technique's validity of acceptance in that community. It does, however, require that the testifying expert understand the technique and its underlying theory, and be thoroughly familiar with the procedures that were in fact used in the case at bar to implement the technique." (People v. Venegas (1998) 18 Cal.4th 47, 81 (Venegas).) Where it is shown that the correct procedures were followed, objections to the techniques go to the weight of the evidence, not its admissibility. (People v. Wright (1998) 62 Cal.App.4th 31, 42.) Likewise, "shortcomings such as mislabeling, mixing the wrong ingredients, or failing to follow routine precautions against contamination, which involve 'the degree of professionalism' with which otherwise scientifically accepted methodologies are applied in a given case, . . . amount only to 'careless testing affecting the weight of the evidence and not its admissibility' ." (Venegas, supra, at p. 81.) As for the second prong of the Kelly test, "the trial court is given considerable latitude in determining the qualifications of an expert and its ruling will not be disturbed on appeal unless a manifest abuse of discretion is shown." (Kelly, supra, 17 Cal.3d at p. 39.) This extends to "the expert who gives testimony on general acceptance--including the issues of his or her credentials and impartiality ." (Ashmus, supra, 54 Cal.3d at p. 971.) Once a new scientific method of proof has been approved in a published appellate decision in California or out of state, the issue of general acceptance is resolved unless a showing is made that the attitude of the scientific community has changed. (Kelly, supra, 17 Cal.3d at p. 32.) However, because the third prong inquiry under Kelly-Frye is case specific, " 'it cannot be satisfied by relying on a published appellate decision.' " (Venegas, supra, 18 Cal.4th at p. 78.)