I agree with the majority that we should adhere to the test articulated in Frye v. United States, 293 F. 1013, 34 A.L.R. 145 (D.C. Cir. 1923) for assessing the admissibility of expert opinion testimony where such testimony is based upon a novel scientific principle. I write separately to emphasize the Frye test applies only to the evaluation of novel scientific theories themselves, and not to differences of expert opinion as to how to apply such theories.
"In the past decade courts have faced the difficult task of ruling on the admissibility of evidence derived from a wide range of newly ascertained or applied scientific principles." Paul C. Giannelli, The Admissibility of Novel Scientific Evidence: Frye v. United States, a Half-Century Later, 80 COLUM. L. REV. 1197, 1198 (1980). The Frye test applies "in cases involving novel devices or processes, such as lie detectors, `truth serum,' identification by human bite marks, microscopic analysis of gunshot residue, and hypnosis." People v. McDonald, 37 Cal.3d 351,690 P.2d 709, 724, 208 Cal.Rptr. 236, 46 A.L.R.4th 1011 (1984).
Thus, the focus of the admissibility question under Frye is on the general acceptability in the relevant scientific *Page 299 community of the new theory advanced. I believe our cases may have gone too far in requiring application of Frye to each and every forensic dispute in the application of a novel scientific theory.
We have said, "If there is a significant dispute between qualified experts as to the validity of scientific evidence, it may not be admitted." State v. Cauthron, 120 Wn.2d 879, 887,846 P.2d 502 (1993). See also State v. Buckner, 125 Wn.2d 915,890 P.2d 460 (1995); State v. Russell, 125 Wn.2d 24, 882 P.2d 747 (1994), cert. denied, 115 S. Ct. 2004, 131 L. Ed. 2d 1005 (1995);State v. Kalakosky, 121 Wn.2d 525, 852 P.2d 1064 (1993). While this statement is correct in the context of a Frye evaluation, it goes too far when read out of context. It seems to imply, incorrectly, that any dispute between experts on any aspect of the forensic application of scientific theory is subject to Frye scrutiny. Thus, the majority here applies Frye to assess the admissibility of the "product rule" for calculating genetic profile frequency. The rules of evidence do not require such dissection.
In Cauthron, for instance, we held DNA typing was generally accepted in the scientific community and was therefore admissible as proof of guilt against the defendant. Cauthron,120 Wn.2d at 899. The validity of DNA typing depends upon the then-novel scientific theory that DNA sequences are unique to each individual. We agreed with the theory, and thereby accepted DNA typing as evidence. We recognized, however, that significant scientific dispute abounded as to the proper handling of DNA samples:
Cauthron, 120 Wn.2d at 898-99.While these problems are of concern, they do not require excluding the evidence altogether. Once the general underlying principles are accepted, as they are here, then both the proponents and opponents of a particular test should be able to garner the necessary information to present both sides of the issue to the factfinder. Any remaining questions about the reliability of the particular tests in this case should be examined under the standards of admissibility of expert testimony, which is within the trial court's discretion. . . . *Page 300 [W]e hold that the problems raised by the defense concerning the quality of the autorads in this case go to the weight rather than the admissibility of the testimony.
Testimony about DNA found at a crime scene involves comparing the frequency of the defendant's DNA sequences with the frequency of naturally occurring sequences. This comparison requires use of a database to determine the frequency with which a particular genetic profile occurs in persons other than the defendant. Accordingly, DNA testimony may not be presented to the jury without an accompanying calculation of genetic profile frequency.Cauthron, 120 Wn.2d at 906.
Here, the State relied on the "product rule" and a particular FBI database to establish the genetic profile frequency. Copeland objects to the use of the product rule because he says it is not generally accepted in the relevant scientific community. The majority embarked upon a lengthy discussion of the product rule before concluding it passes the Frye test. Majority op. at 264-70.
Such analysis was superfluous. There had been conflicting scientific testimony at the trial on the issue, and sufficient information for the jury to decide the matter based on the weight of the evidence. The various views on the applicability of the product rule did not involve questions of novel scientific theory, but rather involved disputed approaches to applying the theory. As we concluded in Cauthron, such questions go to the weight and not the admissibility of the evidence.
Notably, the majority opinion determines that questions about the size or representativeness of the particular database used for the estimate will go to weight and admissibility under ER 702, and not admissibility under Frye. Majority op. at 272-73. "If the principle that frequency calculations can be made from an adequate database is generally accepted, then whether the particular database is large enough [or representative enough] is a question of *Page 301 application of the science to a particular case, i.e., a matter of weight." Majority op. at 272. It would appear that questions of the applicability of the product rule calculation are also a matter of weight and not admissibility.
We must carefully delineate the boundaries of the Frye test so we do not subject each aspect of the forensic application of a novel scientific theory to its rigors. "Frye is not concerned with the acceptance of the results of a particular study or of the particular testing procedures followed in the case before the court." Russell, 125 Wn.2d at 51. Frye is applicable only to the question of whether a novel scientific principle or theory is generally accepted in the scientific community. Once the court, as a matter of law, determines after an appropriate hearing the acceptability of the principle or theory, the court must evaluate the extent to which the evidence applying the principle is admissible through the testimony of expert witnesses. ER 702. The jury, as the trier of fact, determines the weight of the evidence. State v. Lord, 117 Wn.2d 829, 854-55, 822 P.2d 177 (1991) ("expert's lack of certainty goes to the weight of the testimony, not its admissibility."), cert. denied, 506 U.S. 856 (1992). Courts should guard against converting disputes between scientific experts into admissibility issues requiring Frye hearings, and allow juries to exercise their traditional roles as factfinders.
DURHAM, C.J., concurs with TALMADGE, J. *Page 302