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6
DNA Evidence in the Legal System

In the preceding chapters, we have tried to clarify the scientific issues involved in forensic DNA testing. This chapter discusses the legal implications of the committee's conclusions and recommendations. It describes the most important procedural and evidentiary rules that affect the use of forensic DNA evidence, identifies the questions of scientific fact that have been disputed in court, and reviews legal developments.1

All forensic methods for individualization—fingerprints, dental impressions, striations on bullets, hair and fiber comparisons, voice spectrograms, neutron-activation analysis, blood-grouping and serum-protein and enzyme typing, as well as DNA profiling—demand an ability to match samples with reasonable accuracy with respect to characteristics that can help to differentiate one source from another. If such evidence is to be useful in court, scientifically acceptable procedures must permit the reliable measurement and comparison of physical features. Likewise, a scientific basis must exist for concluding that properly performed comparisons can distinguish possible sources.

As to the latter issue—the ability to differentiate between sources—the courts have demanded a more convincing showing of the exact degree of individualization yielded by DNA tests than by any other commonly used forensic technique. Some courts have deemed it necessary for experts not only to demonstrate that DNA profiles usually vary from one person to another, but also to produce

1Unless otherwise indicated, our observations apply to all the technologies for DNA analysis described in this report.



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Page 166 6 DNA Evidence in the Legal System In the preceding chapters, we have tried to clarify the scientific issues involved in forensic DNA testing. This chapter discusses the legal implications of the committee's conclusions and recommendations. It describes the most important procedural and evidentiary rules that affect the use of forensic DNA evidence, identifies the questions of scientific fact that have been disputed in court, and reviews legal developments.1 All forensic methods for individualization—fingerprints, dental impressions, striations on bullets, hair and fiber comparisons, voice spectrograms, neutron-activation analysis, blood-grouping and serum-protein and enzyme typing, as well as DNA profiling—demand an ability to match samples with reasonable accuracy with respect to characteristics that can help to differentiate one source from another. If such evidence is to be useful in court, scientifically acceptable procedures must permit the reliable measurement and comparison of physical features. Likewise, a scientific basis must exist for concluding that properly performed comparisons can distinguish possible sources. As to the latter issue—the ability to differentiate between sources—the courts have demanded a more convincing showing of the exact degree of individualization yielded by DNA tests than by any other commonly used forensic technique. Some courts have deemed it necessary for experts not only to demonstrate that DNA profiles usually vary from one person to another, but also to produce 1Unless otherwise indicated, our observations apply to all the technologies for DNA analysis described in this report.

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Page 167 uncontroversial, quantitative estimates of how rare the identifying characteristics are within particular groups and subgroups. Whether many other forms of identification-evidence could survive comparable demands is doubtful.2 Jurists and legal scholars have debated whether DNA evidence warrants this special treatment.3 We take no sides in such legal debates, but we do emphasize that the two issues—the scientific acceptability of the laboratory method for comparing samples and the idea that the characteristics studied in the laboratory are probative of identity—are distinct. Consequently, this chapter describes the implications of our conclusions about the state of scientific knowledge both for testimony about the extent to which DNA samples match and for testimony about the probabilities of such matches. Legal Standards and Procedures Whether scientific evidence is admissible in criminal cases depends on whether the evidence tends to prove or disprove a fact that, under the applicable law, might matter to the outcome of the case; whether the expert presenting the evidence is qualified; whether the information is derived from scientifically acceptable procedures; and whether the potential for unfair prejudice or time-consumption substantially outweighs the probative value of the information. We discuss those general principles and then consider their application to DNA evidence. We also describe pretrial and trial procedures that might help courts to reach decisions on admissibility and to improve the quality and use of the scientific evidence at trial. We begin with the intertwined procedural issues that arise in connection with a defendant's request for discovery, retesting, or expert assistance. The Defendant's Right to Discovery The 1992 National Research Council (NRC) report stated that ''all data and laboratory records generated by analysis of DNA samples should be made freely available to all parties," and it explained that "all relevant information . . . can include original materials, data sheets, software protocols, and information about unpublished databanks" (NRC 1992, p 150, 148). Certainly, there are no strictly scientific justifications for withholding information in the discovery process, and in Chapter 3 we discussed the importance of full, written documentation of 2 State v Bogan, 905 P.2d 515, 522-23 (Ariz. Ct. App. 1995), rev. granted. 3 State v Bogan, 905 P.2d 515, 522-23 (Ariz. Ct. App. 1995), (dissenting opinion challenging the majority's conclusion that the "'tenuous distinction between molecular genetics and other scientific disciplines' should [not] cause DNA opinion evidence to be treated differently from other opinion testimony that is customarily allowed to support other kinds of scientific evidence") rev. granted; Neufeld and Colman (1990) (advocating more rigorous standards for forensic science generally); Saks and Koehler (1991) (calling for more rigorous validation of many forensic tests).

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Page 168 all aspects of DNA laboratory operations. Such documentation would facilitate technical review of laboratory work, both within the laboratory and by outside experts. The rules of discovery determine the circumstances under which a defendant can compel the production of such records. Because many complex technical, scientific, and statistical issues affect the use of DNA evidence, there will be cases in which defendants will contend that without comprehensive and detailed information, they are unable to prepare for trial adequately.4 Although some courts have ordered liberal discovery, providing access to the documentation and information would broaden the scope of discovery in some jurisdictions. Although some courts have ordered liberal discovery with regard to DNA testing,5 other courts have taken a more restrictive approach.6 In jurisdictions that interpret their discovery rules as applying only to written reports, the defense cannot obtain discovery of laboratory records if the DNA examiner fails to submit a written report or to incorporate a matter into a report, even if the examiner makes an oral report.7 Our recommendation that all aspects of DNA testing be fully 4 State v Schwartz, 447 N.W.2d 422, 427 (Minn. 1989) ("access to the data, methodology, and actual results is crucial so a defendant has at least an opportunity for independent expert review"). 5 See, e.g., United States v Yee, 129 F.R.D. 629 (N.D. Ohio 1990) (even before 1993 amendment to Federal Rule of Criminal Procedure 16(a)(1)(E), a federal magistrate judge granted discovery of matching criteria, environmental insult studies, population data, and proficiency tests as "predicate materials" essential to the defense in a DNA-testing case); State v Schwartz, 447 N.W.2d 422, 427-28 (Minn. 1989) (although a laboratory disclosed its protocol, laboratory notes, autoradiographs, and frequency tables, its refusal to supply "more specific information on its methodology and population data base" was a reason to exclude the findings); People v Davis, 196 A.D.2d 597, 601 N.Y.S.2d 174 (Sup. Ct. 1993) (Lifecodes was required on constitutional grounds to turn over statistical data underlying a DNA probability estimate); cf. State v Feldman, 604 A.2d 242, 244 (N.J. Super. 1992) (defense was entitled to discovery related to a databank search of the Automated Fingerprint Information Service). A few statutes governing the admissibility of DNA tests include provisions for pretrial discovery of the state's report. E.g., 10 Md. Code Ann. Cts. & Jud. Proc. § 10-915(3)(b). 6 See, e.g., State v Dykes, 847 P.2d 1214, 1217-1218 (Kan. 1993) (request of a defendant claiming American Indian ancestry to obtain discovery of a data bank denied, but court permitted discovery of state laboratory's notes, autoradiographs and testing protocol); Spencer v Commonwealth, 384 S.E.2d 785, 791 (1989) (written laboratory reports discoverable, but rules expressly excluded discovery of expert's underlying "work notes [or] memorandum"), cert. denied, 110 U.S. 1171 (1990); cf. United States v Iglesias, 881 F.2d 1519, 1523 (9th Cir. 1989) (discovery of log notes, protocols, or other internal documents of chemists analyzing heroin was denied). 7 See, e.g., United States v Shue, 766 F.2d 1122, 1135 (7th Cir. 1985) (oral report of FBI photographic expert not discoverable pursuant to Federal Rule 16), cert. denied, 484 U.S. 956 (1987). Rule 16 was amended in 1993 to require that the government disclose to a defendant a summary of the expert testimony that the prosecution intends to offer on direct examination and the bases therefore. It is still unclear whether this provision will cause experts to provide more detailed written documentation than they previously furnished. Many states do not have a counterpart to this subdivision. Other jurisdictions make all discovery related to scientific tests discretionary, and still others explicitly provide for the discovery of oral reports of examinations or tests. See Giannelli and Imwinkelried (1993), vol. 1, § 3.2.

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Page 169 documented is most valuable when this documentation is discoverable in advance of trial. Expertise Experts who present and interpret the results of DNA tests must be "qualified by knowledge, skill, experience, training or education" (Fed. R. Evid. 702). There is no well-defined threshold of knowledge or education that a witness must exceed to qualify as an expert. The question is whether the person has enough knowledge "to make it appear that his opinion or inference will aid the trier in the search for truth" (McCormick 1992, § 13, p 54). Because DNA identification can involve testimony as to laboratory findings, statistical interpretation of these findings, and the underlying principles of molecular biology, expertise in several fields might be required. An expert who is qualified to testify about laboratory techniques might not be qualified to testify about molecular biology, to estimate population frequencies, or to establish that an estimation procedure is valid. Consequently, more than one expert witness might be needed.8 Nevertheless, if previous cases establish that the testing and estimation procedures are legally acceptable and if the computations are essentially mechanical, 8 See generally McCormick 1992. § 203, p 875 n 40; Berger 1994, p 63; Kaye and Freedman 1994. p 337. In State v Carter, 246 Neb. 953, 524 N.W.2d 763 (1994), the Nebraska Supreme Court, in reversing a conviction involving a PCR DQA test on the grounds that the 1992 NRC report indicated lack of general acceptance of calculations that assumed Hardy-Weinberg proportions, noted the absence of testimony from a population geneticist. See also Swanson v State, 308 Ark. 28, 823 S.W. 812 (1992) (an argument that a serologist lacked a PhD and was not qualified as an expert in population genetics and therefore could not testify about probabilities was not preserved for appeal): Powell v State, 598 S.W.2d 829 (Tex. Ct. Crim. App. 1994) (argument that molecular biologist should not have been allowed to testify "concerning probabilities of matching DNA patterns because ... the witness had not been qualified as an expert in the field of population genetics" not made at trial, and therefore not preserved for appeal). Trial judges ordinarily are accorded great discretion in evaluating the qualifications of a proposed expert witness, and the decisions depend on the background of each witness. E.g., United States v Davis, 40 F. 3d 1069 (10th Cir. 1994) (the court rejected the argument that a witness "was not qualified to testify regarding population genetics" because ''acceptance of an expert's qualifications will be disturbed only for a clear abuse of discretion" and the witness "had thirteen years experience working for the FBI," "a Master's degree in cell biology," and "six months of specialized training in DNA profiling"): State v McFadden, 458 S.E. 2d 61 (S. Car. 1995) (there was no abuse of discretion in allowing a microbiologist employed by the state's forensic laboratory to testify as to the nature of databases and as to product-rule estimates of 1/(710 million) for blacks and 1/(1.7 billion) for whites); State v Lewis, 654 So. 2d 761 (La. Ct. App. 1995) (the court of appeals held that the trial court abused its discretion by denying expert status to a technician who presented herself as an expert in molecular biology and DNA analysis; the technician had been the assistant director of a laboratory for a year and had no doctoral degree, but belonged to invitational professional organizations, had received numerous academic awards, had testified as an expert in other cases, and had written 14 articles in collaboration with the laboratory director—in promotional rather than scientific publications).

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Page 170 then highly specialized statistical expertise is not essential. Reasonable estimates of allele frequencies in major population groups can be obtained from standard references, and many quantitatively literate experts could use the appropriate formulas in Chapters 4 and 5 to compute the relevant profile frequencies or probabilities. Limitations in the knowledge of a technician who applies a generally accepted statistical procedure can be explored on cross-examination,9 and, if serious questions arise, more knowledgeable specialists can be called to address those questions. In addition to hearing testimony from experts called by the parties, a court may appoint experts to report to it, rather than to the parties.10 Suggestions that court-appointed experts should be used more in science-rich cases have frequently been made (e.g., Fienberg 1989, p 14), but surveys indicate that such appointments are rare (Cecil and Willging 1994, p 529 and n 2). Some issues that arise with regard to DNA testing seem particularly suitable for assistance from a neutral expert. Well-qualified experts could assist a court or jury in understanding basic principles of DNA testing, how such procedures such as RFLP- and PCR-based testing work, and the extent and effect of departures from Hardy-Weinberg (HW) proportions and linkage equilibrium (LE). Court-appointed experts could also provide information about the composition of databases and the scientific literature dealing with specific issues. Some courts have appointed experts to address general questions related to DNA profiling. E.g., United States v Bonds, 12 F.3d 540 (6th Cir. 1993) and United States v Porter, 1994 WL 742297 (DC Super. Ct., Nov. 17, 1994). More controversial is whether a court should appoint its own expert instead of an expert for the defense when there are more specific disputes, such as the precise location of a band on an autoradiograph. A court might conclude that case-specific issues are better resolved with witnesses chosen by and reporting to the parties.11 A court can seek to narrow differences between opposing experts by a variety of techniques. A court could direct experts to address particular issues in their reports or pretrial summaries of testimony. After those have been exchanged, 9 E.g., State v Colbert, 257 Kan. 896, 869 P.2d 1089 (1995) (in view of general acceptance of VNTR databases, estimate of match probability admissible despite expert's concessions that he was not a population geneticist and was not qualified to explain how the databases applied to the town of Coffeyville). 10 In the federal courts, Federal Rule of Evidence 706 authorizes a court to appoint an expert. Many jurisdictions have similar rules. As with the appointment of defense experts, the federal courts have relied on the Criminal Justice Act § 06(A)(E). 11Cecil and Willging (1994, p 542). In some cases, defendants have sought court-appointed experts to review the work of the state's experts. E.g., Taylor v Commonwealth, 1995 WL 808189 (Va. Ct. App. 1995) (unpublished opinion refers to corroboration "by an independent DNA expert appointed by the trial court on defendant's motion"). Other opinions refer to independent experts without indicating the manner of their appointment. E.g., Williams v State, 265 Ga. 351, 455 S.E. 2d 836 (1995) (observing that "an independent geneticist concurred with the DNA findings").

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Page 171 the court could then instruct each side to identify all statements in an opposing expert's opinion that are disputed and to explain the basis for the disagreement. Controverted issues can be further narrowed at a pretrial conference (see Schwarzer 1994). Procedures such as these might, for instance, persuade statistical experts to furnish a best estimate in addition to a range of estimates so that the jury will have a better sense of the degree of disagreement between the two sides. Even if an expert responds that not enough is known as yet to make a statistically valid estimate, the court will have obtained additional information. Having more information may aid a court in ruling on challenges to the admissibility of expert testimony and may enable it to make more effective plans for how the expert testimony should be handled at trial. In some cases, judges have departed from the traditional order of presenting testimony to enable opposing experts to testify consecutively rather than waiting for the prosecution to conclude its case. In appropriate circumstances, courts have allowed an expert's direct testimony to be presented in written or other recorded form rather than in person. General Acceptance and Sound Methodology The technology used to examine VNTRs, STRs, or other loci must satisfy the standard required of scientific evidence. In the United States, two major standards exist for deciding whether scientific findings will be admitted into evidence: the "general-acceptance" test and the "sound-methodology" standard. In addition, some jurisdictions have adopted special statutes that provide for the admissibility of genetic testing in general or of DNA analyses in particular in criminal or civil cases.12If a timely objection is raised, the judge must determine whether the applicable standard has been met. The general-acceptance standard was first articulated in an influential 1923 federal case, Frye v United States, 293 F. 1013 (DC Cir. 1923). In jurisdictions 12 Statutes applicable to criminal cases include 11 Del. Code § 3515; Ind. Code § 37-4-13; 15 La. Stat. Ann. § 441.1; 10 Md. Code Ann. § 915; Minn. Stat. § 634.25; Tenn. Code Ann. § 24-7-117 (1993 Supp.); Va. Stat. § 19.2-270.5; NRC 1992, p 141-142. The Tennessee statute, for example, provides that "in any civil or criminal trial, hearing or proceeding, the results of DNA analysis ... are admissible in evidence without antecedent expert testimony that DNA analysis provides a trustworthy and reliable method of identifying characteristics in an individual's genetic material upon a showing that the offered testimony meets the standards of admissibility set forth in the Tennessee Rules of Evidence" (Tenn. Code Ann. § 24-7-117[b][1]). "DNA analysis" is defined broadly to mean "the process through which deoxyribonucleic acid (DNA) in a human biological specimen is analyzed and compared with DNA from another biological specimen for identification purposes" Id. at § 24-7-117(a). Some statutes explicitly identify a type of DNA analysis, e.g., 10 Md. Code Ann. § 915(b) ("an analysis that utilizes the restriction fragment length polymorphism analysis of DNA"). For discussions, see Moenssens, Starrs, Henderson and Inbau (1995, § 15.20) (surveying criminal and civil statutes); Kaye and Kanwischer (1988) (cataloging civil statutes); Liebeschuetz (1991); Jakubaitis (1991); O'Brien (1994).

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Page 172 that follow Frye, the proponent of the scientific evidence must establish that the underlying theory and methodology are generally accepted within the relevant portions of the scientific community. The biological and technological principles underlying the forensic methods for characterizing DNA variations have generated little controversy in court.13 Indeed, the 1992 NRC report proposed that courts "take judicial notice of [the] scientific underpinnings of DNA  typing,"14and many courts have done so.15 Courtroom debate has revolved instead around the application of those principles to forensic samples and the procedures for declaring a match and interpreting its importance. The sound-methodology  standard is derived from  phrases in the Federal Rules of Evidence. In Daubert v Merrell Dow Pharmaceuticals, 113 S.Ct. 2786 (1993), the Supreme Court held that these rules implicitly jettison general acceptance as an absolute prerequisite to the admissibility of scientific evidence. Instead of the Frye test, the court prescribed a broader framework for deciding whether proposed testimony has sufficient scientific validity and reliability to be admitted as relevant "scientific knowledge" that would "assist the trier of fact." In that 13 For an unusual exception, see Kelly v State, 792 S.W. 2d 579 (Tex. App. 1990) (admitting a VNTR profile match where the state produced five experts who were seriously challenged by only one defense expert, who said that "radioactive technology was too new to be generally accepted in the scientific community"), aff'd, 824 S.W. 2d 568 (Tex. Crim. App. 1992). Although the vast bulk of the cases finding general acceptance have come in the context of VNTR profiling, similar principles and methods of molecular biology underlie the detection of coding DNA polymorphisms, STRs, minisatellite repeat mapping, and the like. 14 When a court takes judicial notice, it accepts a matter as true without requiring that it be proved. Judicial notice is reserved for matters of common knowledge or those that are capable of "accurate and ready determination by resort to sources whose accuracy cannot be questioned" Fed. R. Evid. 201(b). The 1992 NRC report suggested that the following "underpinnings" would be subject to judicial notice (p 149): "The study of DNA polymorphisms can, in principle, provide a reliable method for comparing samples; each person's DNA is unique (with the exception of identical twins), although the actual discriminatory power of any particular DNA test will depend on the sites of DNA variation examined; [and] the current laboratory procedure for detecting DNA variation (specifically, single-locus probes analyzed on Southern blots without evidence of band shifting) is fundamentally sound, although the validity of any particular implementation of the basic procedure will depend on proper characterization of the reproducibility of the system (e.g., measurement variation) and the inclusion of all necessary scientific controls." 15 E.g., United States v Perry, Crim. No. 92-474 (D.D.C. Jan. 11, 1994) (order taking "judicial notice of the reliability of the technique of DNA profiling"); State v Montalbo, 73 Haw. 130, 828 P.2d 1274 (1992) (taking judicial notice that "the DNA paradigm is not controversial and is widely accepted in the relevant scientific community"); People v Adams, 195 Mich. App. 267, 489 N.W.2d 192 (1992) ("trial courts may take judicial notice of the reliability of DNA identification testing," but "the prosecutor must establish in each particular case that the generally accepted laboratory procedures were followed"); State v Woodall, 182 W. Va. 15, 385 S.E.2d 253 (1989) (taking judicial notice of general scientific acceptance where there was no expert testimony, but holding that inconclusive results were properly excluded as irrelevant). But cf. State v Hammond, 221 Conn. 264, 604 A.2d 793 (1992) (''Unlike some courts . . . , we regard DNA typing as too novel for its reliability to be judicially noticed at this time.").

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Page 173 framework, the lack of general acceptance weighs against admissibility but is not invariably fatal. The court discussed other factors that might be considered. Its nonexhaustive list includes the extent to which the theory and technology have been tested, the existence of a body of peer-reviewed studies, and the known error rates of the procedure. Before Daubert, many state and federal courts had construed their rules of evidence as not including a rigid requirement of general acceptance. The 1992 NRC report (p 137) described the "helpfulness standard" used in those jurisdictions as encompassing the following factors: "general acceptance of scientific principles," "qualifications of experts testifying about the new scientific principle, the use to which the new technique has been put, the technique's potential for error, the existence of specialized literature discussing the technique, and its novelty." Since Daubert, many state courts have suggested that their "helpfulness standard" was essentially identical with the approach articulated in Daubert; a few have characterized their rules as more permissive.16 Labels like "general acceptance,"  "sound methodology," and "helpfulness" are just that—labels. Cases decided in each jurisdiction help to define the scientific community in which the degree of scientific acceptance is to be ascertained, the extent of disagreement that can be tolerated, the information that may be used to gauge the extent of consensus, and the specific factors other than general acceptance that bear on relevance and helpfulness.17The degree of scientific consensus is important to the admissibility of scientific evidence in all jurisdictions, and pretrial hearings in hotly contested cases have lasted months and generated thousands of pages of testimony probing the opinions of experts on various aspects of DNA profiling. The courts have examined affidavits or testimony from scientists selected by the parties, specific papers in scientific periodicals, the writings of science journalists, the body of court opinions, and other scientific and legal literature, including the 1992 NRC report. 16 E.g., State v Peters, 192 Wis. 2d 674, 534 N.W.2d 867 (Ct. App. 1995) ("Unlike judges in Frye and Daubert jurisdictions, this role is much more oblique and does not involve a direct determination as to the reliability of the scientific principle on which the evidence is based .... Although Wisconsin judges do not evaluate the reliability of scientific evidence, they may restrict the admissibility of such evidence through their limited gatekeeping functions."). For a survey of the reactions of state courts to Daubert, see Meaney (1995). 17McCormick (1992, § 203). With many, if not most, types of scientific evidence, admissibility does not seem to turn on the choice of the label. For example, by and large, polygraph evidence is inadmissible in both general-acceptance and sound-methodology jurisdictions. With DNA identification, however, a different pattern might be emerging. Over the last several years, appellate courts in Frye jurisdictions have seemed more prone than appellate courts in other jurisdictions to regard the admission of single-locus VNTR tests as error. See State v Anderson, 118 N.M. 284, 295-96, 881 P. 2d 29, 40-41 (1994) (collecting cases); State v Streich, 658 A. 2d 38 (Vt. 1995) ("We note that the courts that refuse to accept statistics based on the unmodified product method continue to rely on the more narrow Frye standard.").

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Page 174 Balancing and Weight Even in jurisdictions where a DNA-identification technology meets the applicable standard of scientific acceptance or validity, the results of particular tests and the manner of their presentation can be subject to challenge. When the dangers of unfair prejudice, time-consumption, and confusion of the issues substantially outweigh the probative value of particular evidence, the trial court should exclude the evidence. E.g., Fed. R. Evid. 403; McCormick 1992, § 185. And even when the court admits expert testimony, the scientific basis and quality of the testimony can be attacked before the trier of fact. Not all expert testimony is equally convincing, and a trier of fact may choose to give admissible evidence little weight in reaching its verdict. Trends in the Admissibility of DNA Evidence Application of the standards for admitting scientific evidence to the admissibility of DNA profile evidence has produced divergent results. In the United States, the first wave of criminal cases involving DNA identification began in 1986.18 The focus was on the problems raised in transferring the technology of modern molecular biology from the medical and genetics laboratories, which usually dealt in fresh samples and easily interpretable diallelic probes, to the forensic laboratory, which must handle aged and exposed stains and usually uses more complex, multiallelic genetic systems. Nevertheless, the underlying theory that DNA profiling is capable of helping to identify the source of a DNA sample was never in doubt, expert testimony for the prosecution was rarely countered, and courts readily admitted the findings of commercial laboratories.19In the wake of those early cases, many experts from several disciplines scrutinized the work of commercial and government laboratories (Kaye 1991, p 357 n 18). The resulting plethora of questions about laboratory procedures and analyses initiated a second wave of cases in which various courts—including the supreme courts of Georgia,20. 18 Blake et al. (1992, p 707) report that "[t]he first use of PCR in a criminal case" occurred in a 1986 Pennsylvania case entitled Commonwealth v Pestinikis. This application of an early form of the DQA test appears to be the first instance of forensic DNA testing of any kind in this country. The first appellate opinion on the admissibility of DNA testing is Andrews v State, 533 So. 2d 841 (Fla. Dist. Ct. App. 1988), and it involved VNTR profiling. 19 See, e.g., Cobey v State, 559 A.2d 391 (Md. Ct. Spec. App. 1988) (prosecution produced five experts to testify to general acceptance of VNTR probes; defense called no experts); Kaye (1991. p 357 n 17); Thompson and Ford (1989). 20 Caldwell v State, 393 S.E.2d 436 (Ga. 1990) (finding Lifecodes "straight binning method satisfactory," but because the laboratory's calculation that the frequency of the profile in the population was 1/24,000,000 rested on the assumption of HW proportions was inconsistent with its database, held that the more conservative figure of 1/250,000 derived from that database would have to be used).

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Page 175 Massachusetts,21 and Minnesota22—excluded at least some aspects of DNA evidence.23 Nevertheless, in most cases, the courts continued to hold DNA matches and probabilities admissible even in the face of conflicting expert testimony.24 After publication of the 1992 report, commentators pointed to "a third wave of cases . . . crashing down upon this battered legal shoreline" (Kaye 1993, p 103). Those cases focused less on the laboratory methods for characterizing and matching DNA and more on the statistical methods for interpreting the significance of similarities in DNA samples. Many opinions in that period lagged behind the scientific publications, which responded forcefully to early speculations and questionable analyses of the importance of departures from the assumptions of statistical independence of alleles within and among VNTR loci. Indeed, some courts reasoned that the movement of scientific opinion was essentially irrelevant under Frye as long as respected scientists continued to oppose the statistical methods. E.g., People v Wallace, 14 Cal. App. 4th 651, 17 Cal. Rptr. 2d 721(1993). Even more recently, with the diffusion of PCR-based methods into the forensic realm, a fourth wave of cases has arrived. The newest cases involve attacks on the procedures for ensuring the accuracy of such analyses and questions about the quantitative interpretation of genetic typing. Again, the underlying theory is not seriously questioned, and laboratories' ability (at least in principle) to obtain informative results is not in dispute. As with the later VNTR profiling cases, defendants have questioned whether the protocols used for forensic work are sufficient to prevent false-positive results, and they have challenged the procedures for estimating the frequencies of the genotypes that are detected after PCR amplification. To clarify the legal relevance of our scientific conclusions 21Commonwealth v Curnin, 565 N.E.2d 440 (Mass. 1991) (holding that Cellmark DNA evidence in a rape case had been erroneously admitted in the absence of a showing of the general acceptance of the validity of the product rule, which gave a frequency of 1/(59 million)). 22 State v Schwartz, 447 N.W.2d 422, 428 (Minn. 1989) (responding to VNTR analysis, said to produce a "banding pattern [whose frequency] in the Caucasian population is approximately I in 33 billion," the court concluded that "DNA typing has gained general acceptance in the scientific community" but that "the laboratory in this case did not comport" with "appropriate standards," and further holding the statistical conclusion to be inadmissible because even if the computation is accurate, "we remain convinced that juries in criminal cases may give undue weight and deference to presented statistical evidence''). 23 Other courts have also refused to admit some forms of DNA evidence. See, e.g., United States v Two Bulls, 918 F.2d 56 (8th Cir. 1990), vacated for rehearing en banc but appeal dismissed due to death of defendant, 925 F.2d 1127 (8th Cir. 1991); People v Castro, 545 N.Y.S.2d 985 (Sup. Ct. 1989); cf. Perry v State, 586 So.2d 242 (Ala. 1991) (remanding for hearing on Lifecodes's adherence to proper procedures and acceptability of statistical methods). 24 See, e.g., United States v Jakobetz, 747 F. Supp. 250 (D. Vt. 1990) (applying relevance standard), affd, 955 F.2d 786 (2d Cir. 1992), cert. denied, 113 S.Ct. 104 (1992); United States v Yee, 134 F.R.D. 161 (N.D. Ohio 1991) (applying general-acceptance standard), aff'd sub nom. United States v Bonds, 12 F.3d 540 (6th Cir. 1993); cf. State v Pierce, 597 N.E.2d 107 (Ohio 1992) (applying relevance standard, no defense experts); Satcher v Commonwealth, 421 S.E.2d 821 (Va. 1992) (applying general-acceptance standard and statute, no defense experts).

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Page 176 and recommendations related to typing methods and statistical issues, we turn now to a more detailed review of these issues as they have arisen in the cases and legal commentary. Typing Methods VNTR Profiling Judicial recognition of the scientific acceptance of the foundations of DNA analysis is consistent with our conclusion that the methods of DNA analysis surveyed in this report are firmly grounded in molecular biology. When VNTR profiling is done with due care, the results are highly reproducible, and comparisons at four or more loci are almost certain to exclude the innocent. To the best of our knowledge, no state or federal court has held that VNTR profiling is inadmissible on the grounds that it is not scientifically accepted or sound.25 Some courts have excluded VNTR matches because of misgivings over the statistical interpretation of the similarities in the profiles (we address this below), but there seems little doubt in the courtroom, as in the laboratory, that properly conducted VNTR profiling is a scientifically acceptable procedure to help to identify the origin of particular biological materials.26 The procedures for matching and binning VNTR  fragments discussed in Chapter 5 have provoked more dissension. Defendants have argued that the "window" within which an examiner may declare that the electrophoretic bands of VNTRs from  two samples of DNA  match is too wide.27 The few  reported opinions to discuss the size of the match window, however, have simply held that the FBI's window is not so large as to render its analyses of VNTR test results inadmissible. As the explanation in Chapter 5 indicates, because wide windows increase the chance that a match will be declared—and at the same time increase the estimates of the frequency of a matching profile—a broad range of match windows is acceptable.28 25 For reviews of the case law, see, e.g., Kaye (1993, 1994); Thompson (1993). It remains possible that some unreported cases have reached a contrary result. 26 E.g., Fishback v People, 851 P.2d 884, 893 (Colo. 1993) (trial courts may take judicial notice of the acceptability of the techniques used in RFLP analysis); State v Moore, 885 P.2d 457 (Mont. 1994) ("the theory underlying DNA and RFLP technology is not open to serious attack"); State v Streich, 658 A.2d 38 (Vt. 1995) (this "part of the scientific debate has essentially ended in favor of DNA admissibility"). 27 United States v Jakobetz, 747 F. Supp. 250 (D. Vt. 1990), aff'd, 955 F.2d 786 (2d Cir. 1992), cert. denied, 113 S. Ct. 109 (1992); United States v Yee, 134 F.R.D. 161 (N.D. Ohio 1991), affd sub nom, United States v Bonds, 12 F.3d 540 (6th Cir. 1993). Those arguments have no application to PCR-based methods that use discrete markers. 28 From a statistical standpoint, the window is best understood in terms of the "standard error" of measurement—a quantity that indicates the variability in repeated measurements of DNA fragments of the same size—and can differ from one laboratory to another. As explained in Chapter 5, match windows must be wider than the normal variability to permit a declaration that two fragments match in most of the cases when they are actually the same length. But the window should not be so wide (footnote continued on next page)

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Page 201 because the proposed LRs do not account for laboratory error, and a jury might misconstrue even a modified version that did account for it as a statement of the odds in favor of S. As for the possible misinterpretation of LRs as the odds in favor of identity, that too is a question of jury ability and performance to which existing research supplies no clear answer. The likelihood ratio is still one step removed from what a judge or jury truly seeks—an estimate of the probability that a suspect was the source of a crime sample, given the observed profile of the DNA extracted from samples. Recognizing that, a number of statisticians have argued that the LR should not be presented to the jury in its own right98 but should be used to estimate the probability that a suspect is the source of a crime sample. E.g., Berry 1991a (but see Berry 1991 b, p 203-204). Thus, a few experts have testified on this posterior probability in court.99 As noted in Chapter 5, the posterior odds (considering the DNA data) that the defendant is the source are the LR times the prior odds (those formed on the basis of other information). That procedure for updating probabilities has a rich history in statistics and law. Known as Bayes's rule, it has been the subject of protracted discussion among legal scholars and statisticians (see generally Allen et al. 1995; Symposium  1991; and Kaye 1988a). One of the more substantial issues raised in the legal scholarship revolves around specifying the prior odds to be updated. For courtroom practice, three methods of presentation have been proposed or used: "expert-prior-odds," "jury-prior-odds," and "variable-prior-odds" (Kaye 1993). In the expert-prior-odds implementation, a scientist implicitly or explicitly selects a prior probability, applies Bayes's rule, and informs the jury that the scientific evidence establishes a single probability for the event in question. The prosecution relied on a Bayesian analysis of this type in State v Klindt, 389 N.W.2d 670 (Iowa 1986), a gruesome chainsaw-murder case decided before the emergence of DNA testing. The supreme court of Iowa affirmed the admission of a statistician's testimony as to a posterior probability in excess of 99% that a torso found in the Mississippi River was what remained of the defendant's missing wife. (It is doubtful, however, that the Iowa courts appreciated the basis of the calculation.) For years, courts in civil paternity cases that involved testing of antigens have routinely admitted testimony of posterior probabilities. E.g.. 98 E.g., Evett 1991, p 201 ("Just leaving a court with a likelihood ratio does not seem enough."): cf. Fienberg 1992 (criticizing presentation of a relative likelihood function). 99 See Smith v Deppish, 807 P.2d 144 (Kan. 1991) (the state's "DNA experts informed the jury that ... there was more than a 99 percent probability that Smith was a contributor of the semen"); State v Thomas, 830 S.W.2d 546 (Mo. Ct. App. 1992) (a geneticist testified that "the likelihood that the DNA found in Marion's panties came from the defendant was higher than 99.99%"): Commonwealth v Crews, 640 A.2d 395, 402 (Pa. 1994) (an FBI examiner who at a preliminary hearing had estimated a coincidental-match probability for a VNTR match "at three of four loci" reported at trial that the match made identity "more probable than not").

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Page 202 Kaye 1989; Aickin and Kaye 1983; and McCormick 1992, § 212. However, the practice has met with much less favor in criminal cases where the experts failed to disclose that they had used an ad hoc prior probability of one-half.100 The expert-prior-odds approach has been criticized as requiring a jury to defer to an expert's choice of the prior odds, even though the scientist's special knowledge and skill extend merely to the production of the likelihood ratio for the scientific evidence (Kaye 1993). Jury-prior-odds implementation requires a jury to formulate prior odds, to adjust them as prescribed by Bayes's rule, and to return a verdict of guilty if the posterior odds exceed some threshold that expresses the point at which the reasonable-doubt standard is satisfied. But that procedure raises serious questions about a jury's ability to translate beliefs into numbers (see Tribe 1971; and Kaye, 1991) and about the desirability of quantifying the vague concept of reasonable doubt (See Nesson 1979, 1985; Shaviro 1989; and Tribe 1971). Finally, with the variable-prior-odds method, an expert neither uses his or her own prior odds nor demands that jurors formulate their prior odds for substitution into Bayes's rule. Rather, the expert presents the jury with a table or graph showing how the posterior probability changes as a function of the prior probability.101 Although the variable-prior-odds implementation of Bayes's rule has garnered the most support among legal scholars and is used in some civil cases, very few  courts have considered its merits in criminal cases.102 How  much it would contribute to jury comprehension remains an open question, especially considering the fact that for most DNA evidence, computed values of the likelihood ratio (conditioned on the assumption that the reported match is a true match) would swamp any plausible prior probability and result in a graph or table that would show  a posterior probability approaching  I except for very tiny prior probabilities. 100 State v Skipper, 228 Conn. 610, 637 A.2d 1101 (1994) (reasoning that this application of Bayes's theorem violated the presumption of innocence and suggesting in dictum that any use of Bayes's theorem would be impermissible); State v Hartman, 426 N.W. 2d 320 (Wis. 1988). The undisclosed use of a prior probability of one-half was standard in civil cases and first was criticized in Ellman and Kaye (1979). The courts that routinely admitted such testimony probably did not recognize the Bayesian nature of the "probability of paternity" laid before them, but courts unmistakably apprised of the foundations of these probabilities have continued to approve of them. A few courts have imposed restrictions on the practice. E.g., Commonwealth v Beausoleil, 490 N.E.2d 788 (Mass. 1986); Plemel v Walter, 735 P.2d 1209 (Or. 1987). For discussion and criticism, see Kaye (1988b, 1989). 101 Finkelstein and Fairley (1970). For LR = 1,000,000, the posterior probability approaches I for all but invisible values of the prior probability. For example, the prior probability would have to be about 1/1,000,000 or less to keep the posterior probability to less than one-half. 102 See State v Skipper, 228 Conn. 610 (1994) (stating in dictum that it would be an error to use the variable-prior-odds approach); State v Spann, 130 N.J. 484, 617 A.2d 247 (1993) (remanding for possible consideration of the use of a Bayesian graph of the probability of paternity). The Skipper opinion is criticized by many of the discussants in Allen et al. (1995).

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Page 203 Importance of Behavioral Research To make appropriate use of DNA technology in the courtroom, the trier of fact must give the DNA evidence appropriate weight. However, unless the results and meaning of the DNA evidence are clearly communicated, the trier of fact may fail to grasp much of the technical merit of DNA profiling. No research has as yet tested the reactions of triers of fact to the detailed presentations of evidence on DNA profiling that are encountered in the courtroom. We do know that people can make frequent and systematic errors in tasks that require them to assess probabilities or to draw inferences using probabilistic information (see, for example, Bar-Hillel 1980; Edwards and von Winterfeldt 1986; Kahneman et al. 1982; Hogarth and Reder 1987; Nisbett and Ross 1980; Nisbett et al. 1983; Palmerini 1993; Poulton 1989). Yet, despite this plethora of research into information processing in other contexts, we know very little about how laypersons respond to DNA evidence and how to minimize the risk that they will give the DNA evidence inappropriate weight. For example, research generally shows that subjects tend to revise their probability estimates in light of new information less than Bayes's theorem would predict (reviewed by Beyth-Marom and Fischhoff 1983), and some research with mock jurors given written descriptions of blood-group evidence and various types of accompanying expert testimony also suggests that jurors will undervalue match probabilities (see Faigman and Baglioni 1988). However, the studies involve far higher match probabilities than the extreme probabilities associated with DNA evidence, which may evoke a different reaction (see Kaye and Koehler 1991). Contextual features, such as the method of presenting a question, that are unrelated to a problem's formal structure may substantially influence probability judgments (Reeves and Lockhart 1993). The small amount of research on reactions to probabilistic evidence suggests that methods of presentation may strongly affect reactions to DNA evidence. Unexamined are the effects of testimony about extreme probabilities or laboratory error when DNA evidence is presented by expert witnesses who are subjected to cross-examination. To evaluate the reactions of laypersons to DNA evidence, research is needed in which the respondents are exposed to the methods of presenting DNA evidence typically used in trial settings. Although scholars have suggested promising ways to present probabilistic assessments in the courtroom (Finkelstein and Fairley 1970; suggesting that jurors be presented with a range of plausible prior probabilities and information about what the likelihood ratio for the trace evidence implies in light of these prior probabilities), almost no empirical evidence yet exists on the effects of such modes of presentation on decisionmakers. Similarly, although some basic probability concepts can be taught to undergraduates in a half-hour with reasonable success (Fong et al. 1986), research is needed on the appropriate way to instruct jurors adequately on the more sophisticated probabilistic concepts at issue when DNA

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Page 204 evidence is presented at trial. If courts are to make informed decisions about the expert presentations that will be allowed or preferred, further research is needed into alternative methods of trial presentation. Conclusions This chapter has described some of the legal principles and procedures governing the admission and use of DNA evidence in the courtroom and how this evidence has been received over the last decade. In assimilating scientific developments, the legal system necessarily lags behind the scientific world. Before making use of evidence derived from scientific advances, courts must scrutinize the proposed testimony to determine its suitability for use at trial, and controversy within the scientific community often is regarded as grounds for the exclusion of the scientific evidence. Although some controversies that have come to closure in the scientific literature continue to limit the presentation of DNA evidence in some jurisdictions, courts are making more use of the ongoing research into the population genetics of DNA profiles. We hope that our review of the research will contribute to this process. In this chapter, we have also discussed how our conclusions and recommendations for reducing the risk of laboratory error, for applying human population genetics to DNA profiles, and for handling uncertainties in estimates of profile frequencies and match probabilities might affect the application of the rules for the discovery and admission of evidence in court. Many suggestions can be offered to make our recommendations most effective: for example, that every jurisdiction should make it possible for all defendants to have broad discovery and independent experts; that accreditation, proficiency-testing, and the opportunity for independent testing (whenever feasible) should be prerequisites to the admission of laboratory findings; that in resolving disputes over the adequacy or interpretation of DNA tests, the power of the court to appoint its own experts should be exercised more frequently; and that experts should not be barred from presenting any scientifically acceptable estimate of a random-match probability. We have chosen, however, to make no formal recommendations on such matters of legal policy; the single recommendation in the chapter concerns scientific evidence—namely, the need for behavioral research that will assist legal decision makers in developing standards for communicating about DNA in the courtroom: Recommendation 6.1: Behavioral research should be carried out to identify any conditions that might cause a trier of fact to misinterpret evidence on DNA profiling and to assess how well various ways of presenting expert testimony on DNA can reduce such misunderstandings. We trust that our efforts to explain the state of the forensic science and some of the social science findings that are pertinent to resolving these issues will contribute to better-informed judgments by courts and legislatures.

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Page 205 Appendix 6A The following tables summarize the law in the United States on the admissibility of estimates of profile frequencies or random-match probabilities of DNA types. Table 6.1 lists the leading cases or statutes in each jurisdiction with a parenthetical explanation of the result in each case. Table 6.2 presents this information in a more abbreviated format. In many of the more recent cases, both an interim-ceiling and product-rule estimates were presented. The tables do not show whether an opinion holds or suggests that the product-rule estimate would have been inadmissible had the ceiling estimate not been included. Many other subtleties and issues that arise in these cases are not captured in this brief summary. TABLE 6.1  Leading Cases and Statutes on Admissibility of Inclusionary DNA Evidence by Jurisdiction, as of June 1995 DC Cir. United States v Perry, Crim. No. 92-474 (D.D.C. Jan. 11, 1994) (VNTR product estimate admissible) 2d Cir. United States v Jakobetz, 955 F.2d 786 (2d Cir. 1992). affd, 955 F.2d 786 (2d Cir.), cert. denied, 113 S. Ct. 109 (1992) (VNTR product-rule estimate admissible under relevance standard) 6th Cir. United States v Bonds, 12 F. 3d 540 (6th Cir. 1993) (VNTR product-rule estimate admissible under Daubert 8th Cir United States v Martinez, 3 F. 3d 1191 (8th Cir. 1993) (testimony of VNTR match without frequency estimate admissible where defendant opposed admission of statistic), cert. denied, 114 S. Ct. 734 (1994) 9th Cir United States v Chischilly, 30 F. 3d 1144 (9th Cir. 1994) (VNTR product-rule estimate admissible under Daubert), cert. denied, 115 S. Ct. 946 (1995) 10th Cir. United States v Davis, 40 F. 3d 1069 (10th Cir. 1994) (VNTR estimate admissible under Daubert, but estimation procedure not specified), cert. denied, 115 S. Ct. 1387, 1806 (1995) Alabama Dubose v State, 662 So.2d 1189 (Ala. 1995) (error not to appoint defense expert to counter what, presumably, was admissible VNTR product-rule estimate and opinion of uniqueness); Perry v State, 586 So. 2d 242 (Ala. 1991) (VNTR product-rule estimate remanded for Frye hearing ), on appeal from remand, 606 So. 2d 224 (Ala. Crim. App. 1992) (admissible Alaska Hilbish v State, 891 P.2d 841, 847 (Alas. Ct. App. 1995) (unstated DNA testing introduced, apparently without objection, to show that blood stain was the victim's to "a certainty of over 99.5 percent") Arizona State v Bible, 175 Ariz. 549, 858 P.2d 1152 (1993), cert. denied, 114 S.Ct. 1578 (1994) (VNTR product-rule estimate inadmissible under Frye because of controversy over sampling method, linkage equilibrium, and Hardy-Weinberg proportions); State v Johnson, 905 P.2d 1002 (Ariz. Ct. App. 1995) (VNTR ceiling estimate admissible under Bible and Frye);State v Bogan, 905 P.2d 515, 522-23 (Ariz. Ct. App. 1995) (RAPD match of DNA from tree and opinion as to source admissible), rev. granted; State v Hummert, 170 Ariz. Adv. Rep. 17 (Az. Ct. App. July 26, 1994) (testimony all but stating that matching VNTR profile is unique inadmissible)

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Page 206 TABLE 6.1 Continued Arkansas Swanson v State, 308 Ark. 28, 823 S.W. 812 (1992) (VNTR product-rule estimate admissible under relevance standard); Prater v State, 820 S.W.2d 429 (Ark. 1991) (same) California People v Admundson, 41 Cal. Rptr. 2d 127 (Ct. App. 1995) (unspecified PCR-based test as well as VNTR profiling) rev. granted (under California Rule of Court 976, opinions of the court of appeals that are under review by the state supreme court are considered unpublished unless the California Supreme Court orders their publication), People v Marlow, 41 Cal. Rptr. 2d 5 (Ct. App. 1995); People v Taylor, 33 Cal. App. 4th 262 (1995); People v Wilds, 37 Cal. Rptr. 2d 351 (Ct. App. 1995),rev. granted; People v Venegas, 36 Cal. Rptr. 2d 856 (Ct. App. 1995), rev. granted; People v Soto, 35 Cal. Rptr.2d 846 (Ct. App. 1994), rev. granted; People v Wallace, 14 Cal. App. 4th 651, 17 Cal. Rptr. 2d 721 (1993); People v Pizarro, 10 Cal. App. 4th 57, 12 Cal. Rptr. 436 (1992); People v Barney, 8 Cal. App. 4th 798, 10 Cal. Rptr. 2d 731 (1992); People v Axell, 235 Cal. App. 3d 836, 1 Cal. Rptr. 2d 411 (1991) (conflicting opinions on admissibility of VNTR product-rule and interim-ceiling estimates) Colorado Lindsey v People, 892 P.2d 281 (Colo. 1995) (VNTR product-rule and ceiling estimates admissible under Frye and relevance standards) Connecticut State v Sivri, 231 Conn. 115, 646 A.2d 169 (1994) (VNTR product-rule estimate admitted at trial, but case remanded for Frye hearing on necessity for interim-ceiling estimate in light of 1992 National Research Council report) Delaware Nelson v State, 628 A.2d 69 (Del. 1993) (trial court's exclusion of VNTR product-rule frequency "inherently inconsistent" with its admission of testimony of a match, because "without the necessary statistical calculations, the evidence of the match was 'meaningless' to the jury"); Del. Code Ann. § 3515 (1994) DC United States v Porter, 618 A.2d 629 (DC App. 1992) (remanding for Frye hearing on admissibility of VNTR ceiling estimates), on remand, 1994 WL 368405 (DC Super. Ct. 1994) (admissible) Florida Hayes v State, 660 So. 2d 257 (Fla. 1995) (VNTR ceiling estimate admissible under Frye; dictum); Andrews v State, 533 So. 2d 851 (1988) (VNTR product-rule estimate admissible under Frye and relevance standards) Georgia Caldwell v State, 260 Ga. 278, 393 S.E.2d 436 (1990) (VNTR product-rule estimate inadmissible because database shows departure from Hardy-Weinberg proportions, but a more-conservative estimate said to be derived without using any "population theory" admissible under Frye); Blige v State, 211 Ga. App. 771, 440 S.E.2d 525 (1994) (estimate produced by "downsizing" the numbers as in Caldwell admissible) Hawaii State v Montalbo, 73 Haw. 130 828 P.2d 1274 (1992) (VNTR product-rule estimate admissible under Frye) Illinois Franson v Micelli, 269 III. App. 3d 20 (1994) (summarizing the positions of each appellate district and holding inadmissible under Frye standard a VNTR paternity probability), appeal allowed, 161 I11. 2d 525, 649 N.E. 2d 415 (1995); People v Heaton, 266 III. App. 3d 469, 640 N.E.2d 630 (1994) (VNTR product-rule estimate and opinion as to source admissible before 1992 National Research Council report); People v Stremmel, 258 N.E.2d 93 (1994) (VNTR product-rule estimate admissible under Frye); People v Watson, 257 III. App. 915, 629 N.E.2d 634 (1994) (VNTR product-rule estimate inadmissible under Frye; remanded for Frye hearing on admissibility of ceiling estimates); People v Lipscomb, 215 I11. App. 3d 413, 574 N.E. 2d 1345 (1991) (VNTR product-rule estimate admissible under Frye)

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Page 207 TABLE 6.1Continued Indiana Harrison v State, 644 N.E.2d 1243 (Ind. 1995) (remanding for Frye hearing on PCR-based tests); Davidson v State, 580 N.E. 2d 238 (Ind. 1991) (VNTR product-rule estimate admissible under Frye); Hopkins v State, 579 N.E. 2d 1297 (Ind. 1991) (same) Iowa State v Brown, 470 N.W.2d 30 (Iowa 1991) (VNTR product-rule estimate admissible under relevance standard) Kansas State v Haddock, 257 Kan. 964, 897 P.2d 152 (1995) (DQA test and frequency admissible under Frye); State v Hill, 257 Kan. 774, 859 P.2d 1238 (1995) (unspecified PCR-based test and frequency estimate admissible under Frye); State v Dykes, 252 Kan.556, 847 P.2d 1214 (1993) (VNTR product-rule estimate admissible under Frye) Louisiana State v Quatrevingt, 617 So.2d 484 (La. Ct. App. 1992) (VNTR product-rule estimate admissible under statute); affd, No. 93-KO-1644, 1996 WL 83873 (La. Feb. 28, 1996) (statute satisfies relevance requirement of Daubert, but Lifecodes's use of monomorphic probes was not shown to be scientifically sound under Daubert); La. Stat. Ann. § 441.1 (1992) Maryland Cobey v State, 80 Md. App. 31, 559 A.2d 391 (1989) (VNTR product-rule estimate admissible under statute); Md. Code Ann. Cts. & Jud. Proc. § 10915(3)(b) (Michie Supp. 1992) ("evidence of a [RFLP] DNA profile is admissible") Mass. Commonwealth v Lanigan, 419 Mass. 15, 596 N.E. 2d 311 (1994) (VNTR ceiling estimate admissible under Frye), appeal of remand from 413 Mass. 154, 596 N.E.2d 311 (1992) (VNTR product-rule estimate inadmissible under Frye) Michigan People v Adams, 195 Mich. App. 267, 489 N.W.2d 192 (1992) (VNTR productrule estimate admissible under Frye), modified on other grounds, 441 Mich. 916, 497 N.W.2d 182 (1993); People v Adell, 205 Mich. App. 326, 517 N.W.2d 785 (1994) (VNTR product-rule estimates admissible under Adams) Minnesota State v Bloom, 516 N.W.2d 159 (1994) (VNTR ceiling estimates admissible under Frye); Minn. Stat. Ann. § 634.25 (1989) Mississipp Polk v State, 612 So.2d 381 (1993) (VNTR match admissible under Frye without frequency estimates) Missouri State v Davis, 814 S.W.2d 593 (Mo. 1991) (VNTR product-rule estimate admissible under Frye), cert. denied, 502 U.S. 1047 (1992) Montana State v Weeks, 270 Mont. 63, 891 P.2d 477 (1995) (serological and VNTR tests along with paternity index of 1,900,000 calculated by unspecified method admissible to prove rape); State v Moore, 268 Mont. 20, 885 P.2d 457 (1994) (VNTR and DQA results admissible under Daubert without any statistical estimates where defendant had moved to exclude estimates as prejudicial) Nebraska State v Carter, 246 Neb. 953, 524 N.W.2d 763 (1994) (PCR DQA product estimate inadmissible under Frye in light of 1992 National Research Council report's discussion of Hardy-Weinberg proportions) New Hamp. State v Vandebogart, 136 N.H. 345, 616 A.2d 483 (1992) (VNTR product-rule estimate inadmissible under Frye; remanded for a Frye hearing on ceiling estimates), appeal after remand, 139 N.H. 145, 652 A.2d 671 (1994) (ceiling estimate admissible under Frye) New Jersey State v Williams, 252 N.J. Super. 369, 599 A.2d 960 (1991) (DQA product-rule estimate admissible under Frye)

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Page 208 TABLE 6.1 Continued New Mexico State v Duran, 118 N.M. 303, 881 P.2d 48 (1994) (VNTR ceiling estimate admissible under Daubert); State v Anderson, 118 N.M. 284, 881 P.2d 29 (1994) (VNTR product-rule estimates admissible under Daubert) New York People v Vann, 627 N.Y.S.2d 473 (App. Div. 3d Dep't 1995) (VNTR product-rule estimate admissible under Frye where the defendant objected that the test was not scientifically accepted but did not object to the frequency estimate); People v Palumbo, 162 Misc. 2d 650, 618 N.Y.S.23d 197 (Sup. Ct. 1994) (DQA test ordered following finding that DQA testing and population frequencies are generally accepted); People v Wesley, 83 N.Y.2d 417, 633 N.E.2d 451, 611 N.Y.S.2d 97 (1994) (VNTR product-rule estimate admissible under Frye): People v White, 621 N.Y.S.2d 728 (App. Div. 3d Dep't 1995) (VNTR test that identified defendant as father of aborted fetus admissible to prove rape) North Car. State v Pennington, 327 N.C. 89, 393 S.E.2d 847 (1990) (VNTR product-rule estimate admissible under relevance standard) Ohio State v Pierce, 64 Ohio St. 3d 490, 597 N.E.2d 107, 113 (1992) (VNTR product-rule estimate admissible under relevance standard); State v Penton, No. 9-91-25 (Ohio Ct. App. Apr. 7, 1993) (DQA estimate admissible under relevance standard) Oklahoma Taylor v State, 889 P.2d 319 (Okla. Ct. Crim. App. 1995) (VNTR product-rule estimate admissible under Daubert) Oregon State v Lyons, 124 Or. App. 598, 863 P.2d 1303 (1993) (DQA product-rule estimate admissible under relevance standard), review allowed, 319 Or. 406, 879 P.2d 1284 (1994); State v Futch, 123 Or. App. 176, 860 P.2d 264 (1993) (VNTR product-rule and [apparently] ceiling estimates admissible under relevance standard), review allowed. 319 Or. 406, 879 P.2d 1284 (1994) Pennsylvania Commonwealth v Crews, 536 Pa. 508, 640 A.2d 395 (1994) (testimony that VNTR match ''at three of four loci" made identity "probable" admissible under Frye despite objection to lack of frequency estimate) South Car. State v Ford, 301 S.C. 485, 392 S.E.2d 781 (1990) (VNTR product-rule estimate admissible under Frye and relevance standards) South Dakota State v Schweitzer, 533 N.W.2d 156, 160 (S.D. 1995) (VNTR estimate admissible under Daubert; method of estimation not specified); State v Wimberly, 467 N.W.2d 499 (S.D. 1991) (VNTR product-rule estimate admissible under Frye) Tennessee State v Steele, No. 03C01-9207-CR-233, 1993 WL 415836 (Tenn. Ct. Crim. App. Oct. 13, 1993) (VNTR product-rule estimate admissible under Daubert); State v Harris, 866 S.W.2d 583 (Tenn. Ct. Crim. App. 1992) (VNTR product-rule estimate admissible under Frye, relevance standard, and special statute) Texas Campbell v State, 910 S.W.2d 475 (Tex. Crim. App. 1995) (DQA estimate admissible under "reliability" standard); Flores v State, 871 S.W. 2d 714 (Tex. Crim. App. 1993) (VNTR product-rule estimate admissible under relevance standard); Kelly v State, 824 S.W. 2d 568 (Tex. Crim. App. 1992) (same); Fuller v State, 827 S.W. 2d 919 (Tex. Crim. App. 1992) (same); Clarke v State, 839 S.W.2d 92 (Tex. Crim. App. 1991) (DQA product-rule estimate admissible under relevance standard) Vermont State v Streich, 658 A.2d 38 (Vt. 1995) (VNTR product-rule estimate, as opposed to a ceiling estimate, inadmissible under Daubert)

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Page 209 TABLE 6.1 Continued Virginia Mickens v Commonwealth, 247 Va. 395, 442 S.E.2d 678 (1994) (VNTR and DQA results admitted at trial but not discussed on appeal); Satcher v Commonwealth, 244 Va. 220, 421 S.E.2d 821 (1992) (VNTR product-rule estimate admissible under special statute); Spencer v Commonwealth, 238 Va. 295, 384 S.E. 2d 785 (1989) (same), cert. denied, 493 U.S. 1093 (1990); Spencer v Commonwealth, 240 Va. 78, 393 S.E.2d 609 (1989) (DQA test result admissible under statute), cert. denied, 498 U.S. 908 (1990); Va. Code Ann. § 19.2-207.5 Washington State v Buckner, 125 Wash.2d 915, 890 P.2d 460 (1995) (testimony that VNTR profile with product-rule estimate of 1/19.5 billion inadmissible); State v Gentry, 125 Wash.2d 570, 888 P.2d 1105 (1995) (DQA product-rule estimate admissible under Frye); State v Cauthron, 120 Wash. 2d 879, 846 P.2d 502 (1993) (VNTR testimony of a VNTR match said to prove that defendant was the source of the incriminating DNA inadmissible under Frye because it was "unsupported by valid probability statistics," but ceiling estimate would be admissible) West Virginia State v Satterfield, 193 W.Va.503, 457 S.E.2d 440 (1995) (unspecified DNA test results admitted at trial but not discussed on appeal) Wisconsin State v Peters, 192 Wis. 2d 674, 534 N.W. 2d 867 (Ct. App. 1995) (VNTR product-rule and interim-ceiling estimates admissible under relevance standard) Wyoming Springfield v State, 860 P.2d 435 (Wyo. 1993) (VNTR ceiling estimate admissible under relevance standard)

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Page 210 TABLE 6.2 Admissibility of Inclusionary DNA Evidence by Jurisdiction, as of June 1995 I103 II III IV V VI VII VIII Jurisdiction Standard Of Admissibility Method Of DNA Test Opinion As To Source Computation Only Fact Of Match Admissible? Product Admissible? Ceiling Admissible? Admissible? DC Cir   RFLP Product     Yes   2d Cir R RFLP Product     Yes   6th Cir F RFLP Product     Yes   8th Cir D RFLP Product     Yes   9th Cir D RFLP Product     Yes   10th Cir D RFLP ?     ? ? Ala F RFLP Product Yes   Yes Yes Ariz F RFLP Product No Yes No Yes   RAPD Ceiling Yes         None     Ark R RFLP Product     Yes   Cal F RFLP,PCR Product     Yes-No Yes-No   Ceiling     Yes-No Yes-No Colo F,R RFLP Product     Yes Yes   Ceiling       Conn F RFLP Product     ?   Del F,S RFLP Product     Yes   DC F RFLP Product     No Yes   Ceiling       Fla F RFLP Product       Yes (Dictum)   Ceiling         Ga F RFLP ?     ?   Haw R RFLP Product     Yes   I11 F RFLP Product     Yes-No   Ind F,S RFLP Product     Yes     PCR           Iowa R RFLP Product     Yes   Kan F RFLP Product       Yes   DQA Product       Yes La R.S RFLP Product     Yes   Md S RFLP Product     Yes   Ma D RFLP Product     No Yes   Ceiling         Mich F RFLP Product     Yes   Minn F,S RFLP Ceiling       Yes Miss F RFLP None   Yes     Mo F RFLP Product   Yes   Mont D RFLP Product     Yes     PCR           Neb F RFLP Product     Yes     PCR           NH F RFLP Product     No Yes   Ceiling         NJ F PCR Product     Yes   NM D RFLP Product     Yes Yes   Ceiling     Yes Yes NY F RFLP Product     Yes   (table continued on following page)

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Page 211 TABLE 6.2 Continued I103 II III IV V VI VII VIII Jurisdiction Standard Of Admissibility DNA Test Method Of Computation Opinion As To Source Admissible? Only Fact Of Match Admissible? Product Admissible? Ceiling Admissible? NC R RFLP Product     Yes   Ohio R RFLP Product     Yes     PCR       Yes   Okla D RFLP Product     Yes   Ore R RFLP Product     Yes     PCR         Yes Pa F RFLP None   Yes     SC F,R RFLP Product     Yes   SD F RFLP Product     Yes   Tenn F,D,R,S RFLP Product     Yes   Tex R RFLP Product     Yes     DQA, PCR           Vt D RFLP Product     No Yes   Ceiling         Va R,S RFLP Product     Yes     DQA Product     Yes   Wash F RFLP Product No   No Yes   PCR           Wisc R RFLP Product     Yes Yes   Ceiling         Wyo R RFLP Product       Yes   Ceiling         103I. Federal or state jurisdiction in which at least one court opinion on the admissibility of DNA test results that incriminated the defendant was reported. II. Frye (F), Daubert (D), relevance-helpfulness (R), or special statutory (S) standard applied. R refers to cases applying a non—Frye standard adopted before Daubert; all federal courts are now required to apply the Daubert standard. III. Type of DNA test performed. IV. Procedure used to compute probability or frequency offered in the case. V. Is expert-opinion testimony that defendant is the source or that the type is unique admissible? VI. Is only the fact of a match admissible? VII. Is the product-rule estimate admissible? VIII. Is the interim-ceiling-principle estimate admissible?