This issue addresses two significant cases from the Sixth Circuit Court of Appeals and one instructive district court opinion. In Best v. Lowe’s Home Centers, Inc., No. 08-5924, 2009 WL 1010883 (6th Cir. April 16, 2009), the Sixth Circuit established specific requirements for the admissibility of expert causation testimony based on a differential diagnosis. In Gass v. Marriott Hotel Services, Inc., 558 F.3d 419 (6th Cir. 2009), the Sixth Circuit reversed the holding of a federal district court in Michigan and allowed a plaintiff to proceed to trial in a toxic tort case without the benefit of causation expert evidence. This seemingly anomalous opinion triggered an aggressive dissent by Chief Judge Boggs, and defense practitioners should be aware of the analysis on both sides of the opinion. Finally, the district court case of Walker v. Louisville Ladder, Inc., No. 3:07-CV-377, 2009 WL 307786 (E.D. Tenn. Feb. 9, 2009) provides a good roadmap for an issue defense practitioners face regularly – the problem of responding to unscientific and speculative opinions offered by scientists who are otherwise well qualified experts that are respected in their field.
Best v. Lowe’s Home Centers, Inc., No. 08-5924, 2009 WL 1010883 (6th Cir. April 16, 2009) rev’g No. 3:04-CV-294, 2008 WL 2359986 (E.D. Tenn. June 5, 2008)
The plaintiff in Best claimed that a container of Aqua EZ pool chemicals spilled on him when he reached for the container while shopping at a Lowe’s hardware store. Plaintiff claimed the container was cut, and that the opening on the container allowed the contents to spill on him. As a result of the exposure he claimed to have lost his sense of smell. The plaintiff offered the testimony of a medical expert who opined that the exposure to the chemicals in the Aqua EZ container caused the plaintiff’s loss of the sense of smell. The district court excluded the proffered expert testimony as unreliable, but the Sixth Circuit, in a detailed opinion which adopted specific criteria for the admissibility of expert testimony based on differential diagnosis, found the testimony sufficiently reliable and reversed. A review of both decisions is instructive, as the district’s court finding of unreliability is at odds with the Sixth Circuit’s differential diagnosis analysis.
The district court, in responding to the defendant’s motion challenging the admissibility of the plaintiff’s expert opinion under Daubert, emphasized the following points from the expert’s deposition:
• He did not review any of the plaintiff’s records and did not know that the medical records indicated the plaintiff denied inhaling the chemical during the exposure;
• He did not know whether plaintiff’s history was of an immediate loss of smell after the exposure;
• He did not know if the chemicals at issue could cause an immediate loss of smell versus a loss over time;
• He did not know the actual amount of the exposure, the amount of chemical spilled, or the length of plaintiff’s exposure;
• He did not know the amount of chemicals which could cause a loss of smell (propenyl chloride or ammonium derivative) that were present in the Aqua EZ product; and
• He did not know the amount of propenyl chloride or ammonium derivative that would cause a loss of smell.
After reviewing these facts from the proffered expert’s deposition testimony, the court relied on a ten year old treatise that identified the following, seven “red flags” which should cause concern for a trial court in making its decision whether to admit scientific evidence:
1. Improper extrapolation;
2. Reliance on anecdotal evidence;
3. Reliance on temporal proximity;
4. Insufficient information about the case;
5. Failure to consider other possible causes;
6. Lack of testing; and
7. Subjectivity.
2008 WL 2359986 at *6-*8 (E.D. Tenn. Feb. 9, 2009) (citing 2 Saltzburg, Martin & Kapra, Federal Rules of Evidence Manual, 1229-37 (7th ed. 1998)). Based on the expert’s deposition testimony, the district court found that the “red flags” identified in points number 1-5 and 7 all weighed against the admissibility of the expert’s proposed testimony. After discussing the application of these red flags to the proposed testimony, the court concluded that the proposed testimony was not based on sound scientific principles, the theory had not been tested or subject to peer review, the potential rate of error had not been determined, and the expert’s belief that the exposure to Aqua EZ could cause a loss of smell had not been accepted by the scientific community. Recognizing its gatekeeping role as determining “whether the evidence is genuinely scientific, as distinct from being unscientific speculation offered by a genuine scientist,” the court concluded the proposed testimony was the latter and granted the defendant’s motion to exclude the expert. Id. at *9 (quoting Downs v. Perstorp Components, Inc., 126 F. Supp. 2d 1090, 1128 (E.D. Tenn. 1999).
On appeal the Sixth Circuit pointed out that the district court failed to recognize that differential diagnosis is an accepted methodology for establishing causation within the circuit and, as a result, applied a de novo standard of review instead of the typical abuse of discretion standard. Relying heavily on the Third Circuit’s decision in In re Paoli Yard PCB Litigation, 35 F.3d 717 (3d Cir. 1994), the Sixth Circuit in Best then established the following test for the admissibility of expert opinions based on a differential diagnosis:
A medical causation opinion in the form of a doctor’s differential diagnosis is reliable and admissible where the doctor (1) objectively ascertains, to the extent possible, the nature of the patient’s injury, (2) “rules in” one or more causes of the injury using a valid methodology, and (3) engages in standard diagnostic techniques by which doctors normally rule out alternative causes to reach a conclusion as to which cause is most likely.
2009 WL 1010883 at *7 (internal quotations and citations omitted). After delineating the elements of the test for admitting differential diagnosis testimony within the Sixth Circuit, the court then turned to the proffered testimony.
The court found that the expert objectively ascertained that the plaintiff had lost his sense of smell by the use of a well recognized test. Despite the defendant’s strenuous argument that the expert could not identify any published materials showing that the chemical in question could cause a loss of smell, the court concluded that the expert had adequately “ruled in” the chemical as a potential cause of the injury. In doing so the court emphasized that “there is no requirement that a medical expert must always cite published studies on general causation in order to reliably conclude that a particular object cased a particular illness.” Id. at *8 (quoting Kudabeck v. Kroger Co., 338 F.3d 856, 862 (8th Cir. 2003)). The court also pointed out that, at least in its view, the expert’s “ruling in” of the chemical was not arbitrary, as the expert relied on his review of the material safety data sheet and his own knowledge of medicine and chemistry.
Finally, the court concluded that the expert adequately “ruled out” other potential causes since the expert eliminated nine of ten medicines the plaintiff took as potential causes of a loss of smell. The defense emphasized the expert’s failure to rule out the tenth medicine as a potential cause, but in response the court noted an absence of any evidence showing that the tenth medicine could cause a loss of smell and stated that an expert “need not rule out every conceivable cause in order for their differential-diagnosis-based opinions to be admissible.” Id. at *9 (citing Westberry v. Gislaved Gummi AB, 178 F.3d 257, 266 (4th Cir. 1999)). Based on this analysis, the court concluded that the expert’s testimony was sufficiently reliable to be admissible.
The Sixth Circuit’s decision in Best is significant for at least two reasons. First, it establishes specific criteria for the admissibility of expert testimony based on a differential diagnosis. Second (and to defense lawyers’ chagrin), it admitted expert testimony that, absent the moniker of “differential diagnosis,” the district court easily determined was unreliable. The decision in Best will likely serve as a road map for plaintiffs to attempt to introduce unreliable expert opinions under the umbrella of “differential diagnosis.”
Gass v. Marriott Hotel Services, Inc., 558 F.3d 419 (6th Cir. 2009)
Gass involved the appeal of a U.S. District Court’s decision in Michigan granting the defendant summary judgment. The plaintiffs were vacationing in Hawaii and, after complaining about a roach in their hotel room, returned to their room later in the day and encountered at least two individuals applying a pesticide (presumably to kill any roaches). Plaintiffs alleged that the air in the hotel room was “sort of cloudy” and that there was a “thick, horrid, acrid putrid odor” in the room. Plaintiffs claimed various injuries as a result of the alleged exposure to the pesticide.
The district court permitted the plaintiffs’ treating physicians to offer expert opinions about the plaintiffs’ illnesses, but it excluded their opinions on causation. The district court also excluded the plaintiffs’ causation experts, and the plaintiffs did not challenge that exclusion on appeal. The Sixth Circuit affirmed the district court’s ruling on the plaintiffs’ experts, but it reversed the district court’s grant of summary judgment, finding that Michigan law did not require expert testimony to prove causation in this case.
Chief Judge Boggs issued a stern dissent, calling the majority’s opinion a classic example of post hoc reasoning. The dissent framed the question as whether the plaintiffs needed expert testimony to prove how much chemical exposure could have caused the alleged harmful consequence, and it answered this question with a resounding yes. Causation questions in pesticide injury cases center upon dose and exposure, and the dissent noted that the plaintiffs’ testimony that the air in their hotel room was “sort of cloudy” and that it had a “thick, horrid, acrid putrid odor” was insufficient to allow a lay jury to determine whether the exposure could have caused the alleged harm.
While the dissent in Gass offers some consolation to defense practitioners, the adoption of the majority’s reasoning in Michigan could significantly lower the burden of proof for plaintiffs to reach a jury in toxic tort cases. Practitioners in the Sixth Circuit should be aware of this decision.
Walker v. Louisville Ladder, Inc., No. 3:07-CV-377, 2009 WL 307786 (E.D. Tenn. Feb. 9, 2009)
Walker v. Louisville Ladder involved claims of personal injury sustained after a fall from an allegedly defective ladder. The plaintiff retained Stanley Kiska as an engineering expert. Mr. Kiska had over twenty years experience in the testing and development of ladders, but he based his opinions in this case on his own “Induced Walking” test. According to Mr. Kiska, his own test was similar to the accepted standard in the industry—the ANSI Racking test for ladders—but he claimed his test more accurately simulated ladder use conditions.
In granting the defendant’s motion to exclude Mr. Kiska’s testimony as unreliable under Daubert, the court concluded that all four of the relevant Daubert factors weighed against the admissibility of his testimony. First, with respect to whether Mr. Kiska’s Induced Walking test could be tested, the court could find no evidence that Mr. Kiska had tested his theory sufficiently such that it could be considered reliable. Mr. Kiska changed his methodology during the series of tests used to develop his opinions for the plaintiff, and he admitted that he did not have any data applying the “new” version of his testing that he developed after different attempts in his testing for the plaintiff. As a result the court concluded that it “simply cannot find the test reliable.”
The second factor, whether Mr. Kiska’s theory had been published or subject to peer review, similarly weighed against admissibility. Mr. Kiska had not sought to publish or otherwise disseminate information about his Induced Walking test, and he was not aware of any other experts in the field using this test. The court found the application of this factor “especially troubling” because Mr. Kiska was the current chair of an ANSI committee for a step-stool safety standard, and he was well acquainted with the relevant field, its peer experts, and the process for adopting new standards. Mr. Kiska’s apparent refusal to subject his newly developed test to the testing process with which he was very familiar called into question any notion of reliability about his new test.
The third Daubert factor, whether there is a known error rate, also weighed against admissibility. There was no known error rate for the test, and Mr. Kiska had only a very small data set consisting only of one series of tests. Mr. Kiska testified that he conducted the tests three to five times, but he did not have that data. Instead, he testified that the test results for which he did have data were “representative” of the other tests. The court concluded that, “[w]ithout some evidence as to the error rate of the Induced Walking test, there is no guarantee the small and unrecorded data set generated in this matter would accurately measure results of [Mr. Kiska’s] own test.”
The court easily addressed the fourth and final factor, whether the theory enjoys general acceptance, as Mr. Kiska testified at a Daubert hearing that his new theory was not used or accepted by anyone else in the field. Although each of these factors weighed heavily against the admission of Mr. Kiska’s testimony, and the court could have concluded its decision based on application of these factors alone, the court also responded to a final argument raised by the plaintiff.
Plaintiff argued that the ladder industry was protected by the relevant ANSI standard, and that it should not be able to insulate itself from liability if a new and proper testing methodology was better than the ANSI standard. In response the court stated:
[T]he court finds that the Induced Walking test is still in the development phase (and has even been revised during the course of this case), and . . . lacks the guarantees of reliability necessary to withstand Daubert analysis. Mr. Kiska testified at the hearing that he had been involved in the development of several ANSI standards. Thus, if the Induced Walking test is a valid form of measurement of the risk of injury to a ladder user, then Mr. Kiska should seek out comment from his peers to confirm that, and perform the additional testing necessary to fully develop his theory, as he has done with the other standards he has helped develop in the past. However, in the absence of such assurances, the Court simply cannot accept Mr. Kiska’s word that the ANSI tests are invalid and that his test is better. If all that were required to pass Daubert was the assurance of the expert that his methodology was reliable, then the Court’s gatekeeping function would effectively be eliminated and abdicated to the expert. That is clearly not Daubert’s goal.
2009 WL 307786 at *7 (emphasis added). The last two sentences of this quotation are a good reminder of the purpose of the four factor analysis under Daubert, and they may be useful in responding to unfounded explanations regarding the proposed reliability of inherently unreliable methodologies, theories or testing.
Eric Hudson is a member of Butler, Snow, O’Mara, Stevens & Cannada, PLLC, in the firm’s Memphis, Tennessee office. He focuses his practice on mass torts, products liability, environmental litigation, and commercial litigation. Eric is involved with the Toxic Torts and Environmental Committee, and when he was a “young lawyer” he chaired the DRI Young Lawyer’s Civility and Professionalism Initiative. He can be reached at Butler Snow, 6075 Poplar Avenue, 5th Floor, Memphis, TN, 38119, 901.680.7309 or eric.hudson@butlersnow.com.
