This appeal requires us to decide whether our per se rule excluding the admission of unstipulated polygraph evidence was effectively overruled by Daubert v. Merrell Dow Pharmaceuticals,
I.
We have long expressed our hostility to the admission of unstipulated polygraph evidence. See United States v. Givens,
In Daubert, the Supreme Court held that Federal Rulé of Evidence 702, governing the admission of scientific expert testimony, superseded Frye v. United States,
The per se Brown rule excluding unstipu-lated polygraph evidence is inconsistent with the “flexible inquiry” assigned to the trial judge by Daubert. This is particularly evident because Frye, which was overruled by Daubert, involved the admissibility of polygraph evidence.
The only other circuit that has squarely addressed this issue held that a per se rule excluding expert polygraph evidence was overruled by Daubert and Rule 702. United States v. Posado,
[W]e do not now hold that polygraph examinations are scientifically valid or that they will always assist the trier of fact, in this or any other individual case. We merely remove the obstacle of the per se rule against admissibility, which was based on antiquated concepts about the technical ability of the polygraph and legal precepts that have been expressly overruled by the Supreme Court.
Id. at 434. We agree with the Fifth Circuit.
This holding is consistent with precedent in this circuit. We have held that Daubert overruled a per se rule excluding expert testimony regarding the credibility of eyewitness identification. See United States v.
Notwithstanding our conclusion, we emphasize that the result we reach in this case is based upon an individualized inquiry, rather than strict application of the past rule concerning expert testimony on the reliability of eyewitness identification. See Amador-Galvan,9 F.3d at 1418 . Our conclusion does not preclude the admission of such testimony when the proffering party satisfies the standard established in Daubert by showing that the expert opinion is based upon “scientific knowledge” which is both reliable and helpful to the jury in any given case. See Daubert,509 U.S. at 591-93 ,113 S.Ct. at 2796 . District courts must strike the appropriate balance between admitting reliable, helpful expert testimony and excluding misleading or confusing testimony to achieve the flexible approach outlined in Daubert. See id. at 595-99,113 S.Ct. at 2798-99 .
Id. at 926.
Accordingly, we hold that Daubert effectively overruled Brown’s per se rule under Rule 702 against admission of unstipulated polygraph evidence.
Brown also suggested that the admission of unstipulated polygraph evidence per se violated Federal Rule of Evidence 403. Brown,
Requiring the trial judge to conduct the Rule 403 analysis is consistent with the law of other circuits. While the Fifth and Sixth Circuits disfavor admission of unstipulated polygraph evidence under Rule 403 when the evidence is introduced to bolster credibility, these circuits still require the trial judge to conduct the balancing test under Rule 403. See United States v. Pettigrew,
With this holding, we are not expressing new enthusiasm for admission of unstipulated polygraph evidence. The inherent problematic nature of such evidence remains. As we noted in Brawn, polygraph evidence has grave potential for interfering with the deliberative process. Brown,
In this ease, Cordoba took an unstipulated polygraph examination. The examiner found
II.
Cordoba appeals the admission of his 1985 conviction of possession with intent to distribute cocaine. We review a district court’s decision to admit evidence of prior convictions under Federal Rules of Evidence 404(b) and 609(a) for abuse of discretion. United States v. Jackson,
We need not address whether Cordoba’s prior conviction was admissible under Rule 404(b). We have held that when a prior conviction is properly admitted under Rule 404(b), then any error in admitting such conviction under Rule 609(a)(1) is harmless. See United States v. Mehrmanesh,
m.
Cordoba also appeals the district court’s admission of expert testimony concerning the modus operandi of drug traffickers. At trial, the government’s expert testified that sophisticated narcotics traffickers do not entrust 300 kilograms of cocaine to someone who does not know what he is transporting.
We review a district court’s decision to admit expert testimony for abuse of discretion. United States v. VonWillie,
If specialized knowledge will assist the trier of fact in understanding the evidence or determining an issue, a qualified expert witness may provide opinion testimony on the issue in question. Fed.R.Evid. 702. The expert testimony that drug traffickers do not use unknowing transporters was clearly probative of Cordoba’s knowledge that he possessed narcotics. See United States v. Castro,
Cordoba further contends that the expert testimony constituted improper drug courier profile testimony. A drug courier profile is a somewhat informal compilation of characteristics believed to be typical of persons unlawfully carrying narcotics, commonly used by agents as a basis for reasonable suspicion to stop and question a suspect. United States v. Lui,
Cordoba also argues that Daubert governs the admission of expert testimony regarding the modus operandi of narcotics traffickers. However, Daubert applies only to the admission of scientific testimony. See Daubert,
IV.
We affirm all rulings except for the district court’s decision to exclude the polygraph examination under Rule 702 and Brown without conducting a particularized inquiry under Daubert. This ease is remanded to the district court to conduct individualized inquiries under Rules 702 and 403 to determine whether Cordoba’s unstipulated polygraph evidence is admissible. If the district court concludes that the unstipulated polygraph evidence is inadmissible under Rule 702 or 403, the district court may reinstate the judgment of conviction. See United States v. Kiser,
VACATED and REMANDED.
