The following is an edited and revised excerpt from Roxanne Bailin, James M. England, H. Patrick Furman, & Edward J. Imwinkelried, Colorado Evidentiary Foundations (Michie 1997). It is reprinted here by permission of the publisher.
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In cases involving novel scientific evidence, Colorado had continued to adhere to its version of the Frye test for a number of years after the Daubert opinion was issued in 1993. See, e.g., Schultz v. Wells, 13 P.3d 846 (Colo. App. 2000) (applying Frye to expert testimony as to whether there was a threshold speed below which whiplash injury does not occur); Smith v. Belle Bonfils, 976 P.2d 344 (Colo. App. 1998), cert. denied (1999) (applying Frye to testimony about proper procedures to prevent use of HIV-infected blood); Tran v. Hilburn, 948 P.2d 52 (Colo. App. 1997), cert. granted and dismissed (1997) (applying Frye to evidence of a quantitative electroencephalogram and video-fluoroscopy); Lindsey v. People, 892 P.2d 281 (Colo. 1996) (applying Frye test to the admissibility of DNA evidence); People v. Lyons, 907 P.2d 708 (Colo. App. 1996) (applying Frye to polygraph evidence). The Colorado Supreme Court reasoned that it was not bound by the United States Supreme Court’s non-constitutional interpretation of Federal Rule 702 even though that rule was identical to CRE 702. Lindsey, supra at 288.
However, in People v. Shreck, 22 P.3d 68 (Colo. 2001), the Colorado Supreme Court significantly modified the approach to scientific theories and principles that should be used in Colorado state courts. Shreck involved the admissibility of DNA evidence generated using the “multiplex technique.” The trial court applied Frye, determined that the technique was not generally accepted by the relevant scientific community, and excluded the evidence. The Colorado Supreme Court reversed, holding “that CRE 702, rather than Frye, governs a trial court’s determination as to whether scientific or other expert testimony should be admitted.” Id. at 69.
The Schreck court indicated that the trial court’s inquiry should focus on reliability and relevance. The reliability inquiry requires the trial court to evaluate the reliability of the scientific principles and the qualifications of the witness. The reliability inquiry should be “broad in nature and consider the totality of the circumstances.” Id. at 70. The factors set forth in Daubert and its progeny certainly may be helpful, but that court rejected any requirement that trial courts consider these factors in every case.
The relevance inquiry under CRE 702 requires the trial court to determine the usefulness of the testimony to the jury. Additionally, the court reminded trial courts to apply the balancing test set forth in CRE 403 “to ensure that the probative value of the evidence is not substantially outweighed by unfair prejudice.”
Although the court refused to require consideration of any particular factor in the determination of reliability, it did note some of the factors that have been considered by other courts in making this determination. The court began with the factors noted in Daubert itself: 1) whether the technique can and has been tested, 2) whether there has been peer review of the technique or theory, 3) whether there are standards and a known or potential error rate for the application of the technique and, 4) whether the technique has been generally accepted. The court went on to note additional factors set out by the Third Circuit in United States v. Downing, 753 F.2d 1224 (3rd Cir. 1985). Those factors are 5) the relationship between the proffered technique and more established techniques, 6) the existence of specialized literature dealing with the technique, 7) the existence and type of non-judicial uses of the technique and 8) whether evidence of the technique has been admitted in other cases.
Applying these considerations to the DNA evidence at issue in Shreck, the Colorado Supreme Court ruled the evidence admissible. The, court first noted that DNA evidence generated through at least two other testing methods is now generally accepted and that the multiplex procedures at issue in Shreck are based on die well-established (polymerase chain reaction) “PCR” system. The court reviewed the trial court’s conclusion that the method had not been sufficiently peer reviewed, and found that a number of foreign studies and two studies conducted in the United States helped establish reliability under CRE 702, even if they did not amount to “general acceptance” under Frye. Additionally, the court found sufficient reliability in the fact that a number of other trial courts have accepted DNA evidence based on multiplex testing, and only one trial court has rejected such evidence.
The court concluded that multiplex testing is sufficiently reliable and that any questions about the specific test kit or testing procedures go to the weight of the evidence, not the admissibility. Finally, the court performed the required CRE 403 balancing and concluded that the probative value of this evidence is not substantially outweighed by the danger of unfair prejudice.
Colorado’s treatment of non-scientific expert testimony has also followed a somewhat different course than the federal treatment. In Brooks v. People, 975 P.2d 1105 (Colo. 1999), the Colorado Supreme Court considered whether dog tracking evidence is “scientific” and thus governed by either the Frye or Daubert tests. The court noted that it had previously ruled that the Frye test should be applied only to “novel scientific devices and processes,” and went on to conclude that dog tracking did not fall within that category because it has been used since the 1800’s and because there are no “infallible scientific devices, processes, or theories” to explain canine scent tracking. The court explained that dog trainers rely on their own experiences and “individualized ‘know-how’ instead of some purportedly universal scientific principle” to gain their expertise. After rejecting Frye, the court concluded that Daubert and Kumho also did not apply. In the court’s view, Daubert applies only to proffered expert testimony based on “scientific knowledge,” which must be derived from the scientific method. The court declined to apply the Daubert test to this type of expert testimony because the experience-based special knowledge of the dog trainer is not dependent on scientific knowledge. The court concluded that a trial court should first analyze the admissibility of this kind of testimony under CRE 702. Once the court determines that the testimony would be useful to the jury, it should move on to CRE 403 and engage in discretionary balancing.
In recent years, but prior to the decision in Shreck, Colorado appellate courts had addressed the admissibility of several types of proffered expert testimony. The Colorado Supreme Court concluded that “drug courier profile” testimony is inadmissible on the issue of guilt because the profile is too subjective. Salcedo v. People, 999 P.2d 833 (Colo. 2000). In People v. Lafferty, 9 P.3d 1132 (Colo. App. 1999), cert. denied (2000), the Court of Appeals approved testimony by a properly qualified expert to testify why alleged domestic-violence victims might recant and change their stories. The court rejected the defendant’s argument that such testimony amounted to an assertion that the victim’s recantation was a lie and that the victim’s first version was truthful. The court reiterated that such credibility testimony remains improper. The court also noted that the trial court properly instructed the jury as to the limited use it could make of the expert testimony. These decisions may need to be reevaluated in light of Shreck.
In Schultz v. Wells, 13 P.3d 846 (Colo. App. 2000), the Court of Appeals considered proffered engineering testimony about automobile collision experiments with human volunteers offered to prove the threshold of force below which a person probably could not be injured in a rear-end automobile collision. Because the court found that such experiments did not “involve a novel scientific process or device applied to the ‘manipulation’ of physical evidence,” and that the jury need not understand highly technical or obscure scientific theories in order to understand the evidence, it ruled that such testimony was governed by CRE 702, not Frye. Id. at 850. The Court also found that the trial court had not abused its discretion in excluding evidence of gravity forces that apply in daily human activities such as coughing, stepping off a curb, skipping rope, riding in “bumper cars,” or being bumped while sitting in a chair. Pursuant to CRE 403, the trial court had discretion to exclude evidence that was misleading in that it “did not take into consideration the entire mechanical movement of the body during a car collision, in that it did not address forces from other directions and the position of the body at the time of the accident.” Id. at 852.