© Copyright. Minnesota Trial (Winter 2010). Posted with permission.
Hardly a case goes to trial these days without an expert witness. Expert witnesses often make or break a case, particularly in a complex products liability case. But trial lawyers often have a difficult time getting that testimony admitted. A lawyer preparing to qualify or challenge an expert at trial must be prepared to overcome a number of hurdles to admit or exclude expert testimony. This article addresses current developments in Minnesota case law and the role of the trial judge in overseeing expert testimony.
Unlike most other states in the nation, Minnesota has declined to adopt the Daubert standard in its state courts. Instead, Minnesota is one of about a dozen states with a Frye or "Frye-plus" standard. Under this standard, scientific evidence and expert opinions must satisfy a test based on Frye v. United States, a case that guided the admissibility of such evidence for many federal and state courts for 70 years before the U.S. Supreme Court's 1993 Daubert v. Merrell Dow Pharmaceuticals decision.
Frye v. United States was a criminal case in which the D.C. Court of Appeals recognized the difficulty in determining the reliability of "scientific" evidence when faced with a challenge to the admissibility of lie detector test results:
Just when a scientific principle of discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle of discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.
The Minnesota Supreme Court adopted Frye's "general acceptance" standard in 1952. And with its 1980 State v. Mack decision, the Court added another consideration -- that evidence must have a scientifically reliable foundation -- to create the two-prong Frye-Mack standard. Under this standard, scientific evidence is admissible in Minnesota courts only when (1) the scientific theory, technique or methodology is generally accepted in the relevant medical or scientific community and (2) the evidence has a scientifically reliable foundation. Of course, proffered evidence must also satisfy the requirements of Minn. R. Evid. 402 and 702 in that it must be relevant and helpful to the trier of fact.
Frye vs. Daubert
Looking at its inauspicious beginnings, the Frye decision was a hidden giant in civil litigation. No other court cited this decision for ten years, and it was only cited thirteen times in the twenty-five years after it was decided. Courts began taking notice of the decision after that, citing the case eighty-three times in the next twenty-five years, but reliance upon the case exploded in the 1970s, perhaps in anticipation of the passage of the Federal Rules of Evidence in 1975. Yet even as the federal courts and many state courts adopted Frye's "general acceptance" standard, it was most often used in criminal cases and cases involving paternity determinations through blood testing. The standard was not applied in a federal civil case until 1984. Even as the use of Frye was expanded in the 1970s and 1980s, the standard was criticized for excluding evidence that was based upon new, but reliable, scientific techniques that had not yet had time to gain acceptance in the scientific community. Further, with the passage of the Federal Rules of Evidence in 1975, there was some confusion over whether the rules superseded Frye and courts were divided about how to properly assess the reliability of scientific evidence.
The Supreme Court faced the issue in 1993 when it decided Daubert v. Merrell Dow Pharmaceuticals. Daubert and its progeny created a multi-prong standard in which "general acceptance" is just one of many considerations that a trial judge may weigh in determining the reliability and admissibility of expert evidence under Rule 702. Other factors include whether the scientific knowledge can be or has been tested, whether it has been subjected to peer review and publication, and whether it has a known or potential rate of error. 
Unlike the United States Supreme Court, the Minnesota Supreme Court has not turned its back on Frye. While many states have adopted Daubert, Minnesota reaffirmed its adherence to the Frye-Mack standard in 2000 with its decision in a products liability case, Goeb v. Tharaldson. In Goeb, a family sued an insecticide manufacturer and an extermination company for ongoing symptoms the family experienced, which started while living in a rental home. While Frye-Mack, like Daubert, casts the judge in a gate-keeping role to ensure reliability of expert testimony, the Minnesota Supreme Court rejected Daubert for several reasons. The court in Goeb noted that Daubert requires judges to be "amateur scientists," whereas Frye-Mack ensures that those most qualified to assess the scientific method (i.e., the relevant scientific community) have the "determinative voice" in the admissibility of the evidence. The court recognized that it was adopting a more conservative standard than the federal Daubert standard, pointing out that "because Daubert stresses a more liberal and flexible approach to the admission of scientific testimony, it has been viewed as relaxing the barriers to the admissibility of expert evidence." The 2006 Amendments to the Minnesota Rules of Evidence incorporated the two-pronged Frye-Mack test into Rule 702.
While the trial judge serves as gatekeeper under both tests, Frye-Mack requires Minnesota state courts to defer to the scientific community in determining the reliability of evidence. One advantage of Frye-Mack, then, is that it does not force judges to evaluate the science underlying an opinion. This carries with it, however, the risk that the jury may be deprived of helpful testimony because scientists are required to prove that their conclusions are generally accepted. Thus, a scientist may have conducted his research appropriately, but if he is the first to reach a particular conclusion, then Frye-Mack would arguably exclude that testimony. Daubert, instead, relies on whether or not the expert applied appropriate methodology in reaching the conclusion, not on whether the conclusion itself has gained acceptance. The two tests have different standards of review. Under Daubert, the question is whether the trial court abused its discretion in admitting or excluding expert testimony, whereas under Frye-Mack, general acceptance is reviewed de novo.
Recent Products Liability and Other Notable Decisions
- Goeb v. Tharaldson
The Minnesota Supreme Court affirmed its adherence to Frye-Mack and explicitly rejected Daubert in this 2000 products case. Three members of the Goeb family became ill shortly after they moved into a house that had been recently treated with the insecticide, Dursban. They moved out, but their symptoms continued. The Goebs sued the pesticide applicator and Dow, the manufacturer of Dursban. Dow moved to exclude the testimony of two of plaintiffs' expert witnesses, arguing that they had failed to follow proper methodology in determining that plaintiffs' exposure to Dursban was the cause of their symptoms. The trial court granted the motion, and granted summary judgment to Dow. The Minnesota Court of Appeals affirmed and review was granted by the Minnesota Supreme Court. The Minnesota Supreme Court re-affirmed that Frye-Mack is the appropriate standard for the admissibility of expert testimony in Minnesota. The court rejected Daubert, criticizing it for requiring judges to be "amateur scientists," whereas Frye-Mack ensures that those most qualified to assess the scientific validity of a technique - i.e., the scientists - have the "determinative voice." The court also voiced concern that Daubert could lead to non-uniformity, since cases with similar expert testimony could lead to varying decisions on admissibility. Ultimately, the court affirmed the decision to exclude the expert testimony, but explicitly decided not to conduct a de novo review on the Frye general acceptance prong. Instead, the court found the Mack prong dispositive, holding that the district court did not abuse its discretion because the record clearly supported that the experts' methodology lacked a reliable foundation. Noting that the plaintiffs had the burden of establishing that the methodology and the results from the methodology were reliable, the Minnesota Supreme Court faulted the plaintiffs for failing to provide independent validation of the experts' methodology and instead only responding to defendants' arguments by referencing the experts' strong qualifications and referring the court to the arguments in their affidavits. Finally, the court affirmed summary judgment for the defendants because there was no expert testimony on medical causation.
- Timmer v. Shanineau Adventures
Noting that the "decision to admit expert opinion testimony is within the broad discretion of the district court," the appellate court affirmed the lower court's decision to admit plaintiff's engineer expert opinion. The appellate court confirmed that a Frye-Mack analysis was not necessary on the engineer's expert opinion on the safety of a zip line landing site because his analysis did not involve a novel scientific theory. The testimony was properly admitted because the expert's experience, background, and investigation provided proper foundation under Minn. R. Evid. 702.
- Pribyl v. StrikeMaster Corp.
In this products case alleging that a StrikeMaster Ice Auger caused injuries that caused the development or reactivation of plaintiff's latent multiple sclerosis, the district court applied a Frye-Mack analysis and excluded plaintiff's two expert opinions. While under the Mack prong, the court found that the expert's "test" used to establish MS - a differential diagnosis - provided a reliable foundation for his opinion, the court excluded the experts under the general acceptance prong. The court found that an article published by the American Academy of Neurology represented the opinion of the international community of neurologists and since the plaintiff's experts disagreed with this position, their opinions were not generally accepted by the neurological scientific community. Furthermore, the court found that the experts relied too heavily upon the temporal relationship between the trauma and MS development, did not provide a mechanism for the injury, and did not exclude other possible causes. Finally, the court rejected plaintiff's arguments that defendants had the burden to show that the scientific evidence was not novel.
- Wilhelm v. St. Jude
This case involved claims that St. Jude's aortic connection used in bypass surgery was defective. The district court found that the proffered experts' opinions lacked reliable foundation and granted defendant's motion for summary judgment. The court did not mention the Frye-Mack standard by name, but did cite Goeb in holding that an expert's opinion must have reliable foundation, which must include a reliable differential diagnosis to rule out all other probable causes. Here, the court found that the experts did not conduct a differential diagnosis and did not rule out other factors as less plausible causes of plaintiff's injuries. Of note, the court also held that the failure-to-warn claim could not survive summary judgment because there was no evidence that the treating surgeon's off-label use of the product would have differed with stronger warning language.
- Hayle v. Dorel Industs., Inc.
In this products case against a car seat manufacturer and others, the district court ruled that the challenged expert opinions satisfied the Frye-Mack test and were admissible. Defendant argued that the experts lacked foundational reliability because their testing contradicted the generally-accepted methodology that one of the experts expounded. Calling this "classic cross-examination material," the court noted that an expert statement provided by defendants which contradicted the plaintiff's expert may affect credibility, but it did not render plaintiffs' testing unreliable or inadmissible. In reaching this decision, the court gave substantial weight to expert affidavits the plaintiffs submitted in response to defendant's methodology criticisms. In those affidavits, the plaintiffs' experts explained they did consider the data that the defendant claimed they did not, but that this that data did not change their opinions.
- Brandt v. Western Wisconsin Med. Assoc., S.C.
In Brandt, the Court of Appeals affirmed the district court decision to allow expert testimony to stand after it was challenged in post-trial motions. The defendant did not object to the expert's qualifications in limine or at trial during the testimony. Instead, defendant raised the issue for the first time in a motion for judgment as a matter of law, after plaintiff rested his case. Defendant contended that he was unable to challenge the qualifications earlier because he did not depose the doctor, as expert witness depositions require leave of the court. The appellate court noted there was no indication in the record that defendant ever brought a motion for leave to depose the doctor, and that defendant did not ask to conduct a voir dire examination of the expert to assess his qualifications. Rather, the defendant first raised the issue of the expert's qualifications after the expert had completed his testimony, when plaintiff was unable to respond to the objection by providing additional foundation for the expert's testimony. Plaintiff did not assert that defendant waived the objection, but it appears that the court would have accepted a timeliness argument. Ultimately, however, the court found that the district court did not abuse its discretion in admitting the expert testimony.
- Zandi v. Wyeth
The Minnesota Court of Appeals upheld the trial court's decision to exclude plaintiff's two experts on whether plaintiff's 20-year use of hormone replacement therapy specifically caused her breast cancer.
Applying a Frye-Mack analysis, the appellate court held that plaintiff failed to establish there is a generally-accepted method of diagnosing the cause of hormone-dependant breast cancer in individuals. In this case, the treating doctor and the defense expert agreed that there is no way to determine the cause of breast cancer in a specific patient. The court rejected each basis relied upon by plaintiff's experts - epidemiological studies, differential diagnosis and a test measuring the percentage of dividing cells - for causation. The court found that plaintiff did not introduce any evidence tending to show that the medical community generally accepts differential diagnosis as a method for diagnosing breast cancer. The court noted: "Breast cancer does not lend itself to differential diagnosis because the scientific community has not accepted that breast cancer has a limited number of discrete and recognized possible causes such that ruling out one cause would implicate another." The proffered expert testimony was unreliable and thus inadmissible because the testimony was based on a faulty differential diagnosis analysis. Specifically, the experts could not "rule out" plausible causes of plaintiff's injury since the alleged injury could be idiopathic. For example, as the plaintiff's sister had breast cancer, the court also noted that family history could not be ruled out as a cause without evaluating the sister. The court also undercut the expert's reliance on epidemiological studies, noting that they cannot solely establish specific causation.
Unfortunately, defendants sometimes mistakenly argue this case means that a differential diagnosis alone is an unreliable method to determine specific causation where the plaintiff's alleged injury has unknown causes. The 8th Circuit, however, recently disagreed with the ruling in Zandi, noting that Minnesota law requires a more conservative review of expert testimony than does Daubert: "To the extent that Zandi excludes an expert opinion that relies on differential diagnosis to determine the cause of hormone-receptor-positive breast cancer in an individual with hormone-dependent breast cancer, we respectfully disagree." Nonetheless, the Zandi case demonstrates that Frye-Mack requirements on admissibility of expert testimony can be more restrictive than those imposed under Daubert.
- Lyford v. Thienprasit
After holding an evidentiary hearing as requested by defendant, the district court denied defendant's motion to exclude plaintiff's neurosurgeon expert in a case alleging negligent post-operative care resulting in the delay of a second lumbar spine surgery and permanent injuries. The court reasoned that the expert's opinions were not novel within the relevant scientific community and there was sufficient foundational reliability. The court specifically noted that since the expert's opinions were similar to plaintiff's treating physicians, it was difficult to see how they could be considered novel.
Frye-Mack in Your Products Liability Case
Frye-Mack can be a powerful weapon in the products liability practitioner's toolbox. Like Daubert, Frye-Mack challenges are generally directed against expert witnesses used by plaintiffs. Plaintiffs should be prepared to defend their expert's testimony against a Frye-Mack challenge whenever a "novel" scientific technique is introduced. Without the expert testimony, a plaintiff's case may be torpedoed.
The burden firmly remains on the party proffering the expert to establish (1) general acceptance and (2) proper foundational facts. Unlike under Daubert, the general acceptance standard applies not only to the expert's methodology, but may also apply to his or her conclusions. To avoid these burdens, the key inquiry is whether the theory or technique is "novel," not the subject matter.
Courts often struggle with whether the testimony concerns "novel scientific evidence" that must be subject to the rigors of the Frye-Mack test. Rule 702 does not define what is novel, instead leaving this question to the courts. Thus, if the proffered expert testimony includes opinions that have long been admitted, the burden of showing "general acceptance" disappears. For example, in Richert v. Madison, a Ramsey County District Court judge found that opinions relating to the use of a Neuroform stent in a patient who has not been pretreated with platelet-inhibited medications is not subject to a Frye-Mack analysis because the procedure was not novel. Similarly, in Timmer v. Shamineau Adventures, the court found that expert testimony as to the safety of a zip line landing area "did not constitute ‘novel scientific testimony' and a complete Frye-Mack analysis was not necessary." Finally, note that it appears the party proffering the expert testimony bears the burden to showing that the proffered evidence is not novel, when faced with a Frye-Mack challenge.
If "novel" science is at issue, the burden of proof lies with the proponent of the scientific evidence, who must show that her novel scientific evidence meets both prongs of the Frye-Mack standard. Whether a novel scientific technique is generally accepted within the relevant scientific community oftentimes requires an evidentiary pre-trial hearing. If the "scientific technique that produces the scientific evidence is no longer novel or emerging, then the pre-trial hearing should focus on the second prong of the Frye-Mack standard."
Because of the evidentiary requirements of a Frye-Mack hearing, the motions may be more effective at summary judgment rather than the motion in limine stage. Counsel may use the information statement and discovery conference to schedule deadlines for expert disclosures, motion, and possibly Frye-Mack hearings. If a Frye-Mack hearing occurs, a practitioner must be prepared to present through affidavit or testimony that her expert's techniques have gained acceptance in the relevant scientific community. Unfortunately, there are ambiguities in the Minnesota case law as to how to determine the relevant field, whether "general acceptance" requires a consensus, and how a consensus is proven (e.g., majority, substantial minority?). All of these questions require careful planning before submitting an expert report on novel scientific issues. If these issues are not anticipated in advance, then you may find yourself with no expert and with no feasible way to win at trial.
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