meaningful standard that was lacking in criminal cases and that it would serve to protect innocent defendants.

[However, a]n analysis of post-Daubert decisions demonstrates that whereas civil defendants prevail in their Daubert challenges, most of the time criminal defendants almost always lose their challenges to government proffers. But when the prosecutor challenges a criminal defendant’s expert evidence, the evidence is almost always kept out of the trial…. In the first 7 years after Daubert, there were 67 reported federal appellate decisions reviewing defense challenges to prosecution experts. The government prevailed in all but 6, and even among the 6, only 1 resulted in the reversal of a conviction. In contrast, in the 54 cases in which the defense appealed a trial court ruling to exclude the defendant’s expert, the defendant lost in 44 cases. In 7 of the remaining 10, the case was remanded for a Daubert hearing.45

This critique of reported federal appellate decisions cannot be the end of the analysis, however. First, there are two sides to any discussion concerning the admissibility and reliability of forensic evidence: (1) enhancing the ability of law enforcement to identify persons who commit crimes and (2) protecting innocent persons from being convicted of crimes that they did not commit. It is easier to assess the latter than the former, because there are no good studies indicating how many convictions are lost because of faulty forensic science evidence. Second, if one focuses solely on federal appellate decisions, the picture is not appealing to those who have preferred a more rigorous application of Daubert. Federal appellate courts have not with any consistency or clarity imposed standards ensuring the application of scientifically valid reasoning and reliable methodology in criminal cases involving Daubert questions.46 This is not really surprising. The Supreme Court itself described the Daubert standard as “flexible.” This means that, beyond questions of relevance, Daubert offers appellate courts no clear substantive standard pursuant to which to review decisions by trial courts.47 As a result, trial judges exercise great discretion in deciding whether to


Ibid., p. S109. See also P.C. Giannelli. Wrongful convictions and forensic science: The need to regulate crime labs. 86 N.C. L. REV. 163 (2007).


See, e.g., United States v. Brown, 415 F.3d 1257 (11th Cir. 2005); United States v. Havvard, 260 F.3d 597 (7th Cir. 2001). The Havvard decision has been described as “[a]n excellent, albeit deeply troubling, example of a court straining scientific credulity for the sake of a venerable forensic science.” See 1 Faigman et al., op. cit., supra note 1, § 1:30, pp. 85-86.


As noted above, “whether Daubert’s specific factors are, or are not, reasonable measures of reliability in a particular case is a matter that the law grants the trial judge broad latitude to determine.” Kumho Tire, 526 U.S. at 153.

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