The first published case on Wisconsin’s (relatively) new rule on expert opinion testimony has emerged at long last. In 2011 the legislature replaced Wisconsin’s decade’s-old approach with the federal “Daubert rule,” a rule rejected by state appellate courts on several occasions. The old rule left disagreements among experts mostly to the trier of fact, provided the witnesses had suitable specialized knowledge that could assist in fact finding. The current Daubert rule unctuously anoints trial judges as “gatekeepers” responsible for ensuring that only “reliable” expert opinions are put before juries. Many critics, me included, thought the old rule served the same purpose quite well. In State v. Giese, 2014 WI App 92, the court of appeals wisely signals that the new rule is mostly compatible with the older approach.
Giese was found asleep, reeking of alcohol, in a roadway about three miles from where he crashed his car. A blood test hours later showed a BAC of 0.181, but the critical question was his BAC at the time of the crash. In defending himself against OWI charges, Giese challenged the admissibility of testimony by a toxicologist based on “back extrapolation,” namely, her projection of Giese’s blood alcohol level four hours before he gave a blood sample. The trial judge, applying the Daubert standard found in current Wis. Stat. § 907.02, ruled that the opinion testimony was admissible. The defendant appealed this nonfinal order.
The court of appeals affirmed in an opinion by Judge Brown. “The standard is flexible,” said the court, “but has teeth. The goal is to prevent the jury from hearing conjecture dressed up in the guise of expert opinion.” (¶ 19) Excluded, then, is “ipse dixit” testimony, when a witness relies on credentials rather than a reliable methodology. (¶ 20) The trial record showed “the general acceptance of retrograde extrapolation in the field of toxicology and its widespread admission by state courts.” (¶ 24) The expert’s opinion was supported by more than a single test result: “Giese was found lying in a roadway at 2:12 a.m.; he said he had crashed his vehicle three hours earlier, started walking away from the scene, and fell asleep in the road; there were no bars or restaurants along the route he walked and no alcohol containers found in his car or along that route; and his blood sample drawn an hour or so later had a blood alcohol concentration of .18.” (¶ 25) Giese’s “real dispute” was less with the science than the factual assumptions the expert made; thus, his “questions go to the weight of the evidence, not to its admissibility.” (¶ 28)
A single case does not a trend make, yet some generalizations may be drawn. First, methods and techniques blessed by pre-2011 case law will likely satisfy the current rule. Second, general acceptance by experts in the field is a compelling sign of reliability; unanimity among them is not required. Third, expert opinions must be based on sufficient facts and data, yet disagreements over the underlying facts (e.g., When did Giese stop drinking?) run to weight, not admissibility. Finally, the new rule’s “teeth” will be flashed when witnesses try to fob off speculation as opinion, especially when based on ipse dixit testimony.