Guerre-Chaley v. State

In Guerre-Chaley v. State, 88 P.3d 539 (Alaska App. 2004) the defendant argued that a preliminary breath test result should be admissible under Evidence Rule 703 when offered as the basis for a defense witness's expert opinion that a later DataMaster test result was untrust worthy. When the trial judge asked the defendant to prove, as a foundational matter, that the preliminary breath test met the Daubert-Coon standard for the admission of scientific evidence, and when the judge offered to hold a hearing so that the defendant could present evidence on this issue, the defendant declined. Instead, the defendant argued that the evidence was admissible even if the preliminary breath test device did not meet the Daubert-Coon test. The Court concluded that the offered evidence was inadmissible unless the defendant demonstrated that the preliminary breath test device met the Daubert-Coon test: As a matter of law under Daubert and Coon, experts can not reasonably rely on the results of a test that has no demonstrable scientific validity. Whenever an expert witness proposes to base an opinion or inference on data derived from a test that has no demonstrable scientific validity, that data will have little or no probative force in support of the expert's opinion, while at the same time there will obviously be an overriding danger that the data will be used for an improper purpose -- the improper purpose of lending the aura of scientific respectability to an assertion that has no basis in science. (Guerre-Chaley, 88 P.3d at 543-44.)