Opinion ID: 1438901
Heading Depth: 1
Heading Rank: 6

Heading: admissibility of matching dna evidence without corresponding statistical evidence

Text: The State characterizes the trial court's admission of the DNA matching evidence while excluding the State's statistical evidence as of doubtful validity. We go further and find the ruling erroneous as a matter of law. We hold that DNA matching evidence is inadmissible in the absence of a statistical interpretation of the significance of the declared match. Accordingly, admission of only one of these components without the other renders all of the DNA evidence inadmissible. We so hold for the following reasons. The three-step process of DNA typing produces two distinct, but interrelated, items of information: 1) whether a match exists between the samples; and 2) if a match exists, the ratio expressing the statistical likelihood that the crime scene samples came from a third party who had the same DNA pattern as the suspect. Barney, 10 Cal.Rptr.2d at 736; see also Vandebogart, 616 A.2d at 486. The latter correlation is necessary because, even though two human genomes may vary at approximately three million sites, the DNA typing analysis currently employed examines only a few sites for variation in the DNA sequence. DNA Committee Report at 74. The theory is that, besides identical twins, no two individuals will have entire DNA sequences which are identical. The DNA prints which result from the current FBI procedure may not be unique since the entire DNA molecule is not analyzed. Since two unrelated individuals may have identical DNA patterns from the fragments examined in a particular analysis, the potential exists for a match to be mistakenly found. Id. For this reason, statistical interpretation regarding the probability of a coincidental match or the likelihood that two unrelated individuals have the same DNA type is necessary. The Committee on DNA Technology in Forensic Science has stated: To say that two patterns match, without providing any scientifically valid estimate... of the frequency with which such matches might occur by chance, is meaningless. DNA Committee Report at 74 (emphasis added). Several courts consider the statistical calculation (third) step as the more important of the two pieces of information which constitute DNA evidence. See, e.g., Porter, 618 A.2d at 640 (statistics are an integral part of DNA evidence and essential); Barney, 10 Cal.Rptr.2d at 742 (statistical calculation is pivotal element of DNA analysis). Whether the statistical evidence is labeled integral or pivotal, the statistical calculation is essential for the evidence to have relevance or meaning to the trier of fact. Since the issuance of the DNA Committee Report, an overwhelming majority of courts have excluded the evidence of a match after finding the corresponding statistical calculation to be inadmissible because not scientifically reliable. See Cauthron, 846 P.2d at 516 (citing Commonwealth v. Curnin, Mass.Supr., 409 Mass. 218, 565 N.E.2d 440, 442 n. 7 (1991) and Ex parte Perry, Ala.Supr., 586 So.2d 242, 254 (1991)); Vandebogart, 616 A.2d at 494 (evidence of match not admissible if not accompanied by scientifically reliable population frequency estimate); Lanigan, 596 N.E.2d at 314 (match evidence cannot be admitted without appropriate statistical support); Barney, 10 Cal.Rptr.2d at 745; but see Pierce, 597 N.E.2d at 115 (statistical calculations go to the weight, not admissibility of DNA evidence). [9] We adopt this view and hold that DNA evidence is only admissible when both the evidence of a match and the statistical significance of the match are admissible. Thus, we reject the State's overly simplistic argument that statistics go simply to the weight, not the admissibility of the DNA matching evidence. We find the Superior Court's rationale for admitting the State's evidence of a match while excluding its proffered statistical interpretation of the match to be flawed. The court excluded such evidence not on its own merits or for a found lack of reliability, but out of concern that the statistics would be overly prejudicial to the defendant and possibly confusing or misleading to the jury. The court's reference to Nelson's indigency seems misplaced, in the absence of any record evidence of an application for funds to employ an expert. In any event, we find the court's ruling inherently inconsistent since, without the necessary statistical calculations, the evidence of the match was meaningless to the jury and, thus, inadmissible. See DNA Committee Report at 74-75. We need not consider or address other questions raised relating to the admissibility of DNA evidence, including whether the DNA typing procedures used by the FBI or the method used to calculate the statistical significance of a match are admissible under the Delaware Rules of Evidence. We decline to address these and related questions due to the inadequate record in this case. We only hold that, for DNA evidence to be admissible, both the procedures used to obtain a match and the statistical evidence interpreting the significance of a match must satisfy the Delaware standard applicable to the admissibility of scientific evidence. See generally section IV, supra. We would also suggest that in any subsequent DNA case a trial court should consider the DNA Committee Report and any other peer literature related to this rapidly advancing scientific field.