Ipse Dixit and analytical gap haunt yet another expert witness

Ipse dixit is the Latin term for “He, himself, said it.”  In ipse dixit, there is a presumption that the speaker is making an arbitrary assertion and expects the listener to accept it without question.  An expert witness’ use of and reliance upon an ipse dixit assertion, in the absence of other substantive bases for an opinion, often leads to an exclusion under Daubert.

The Roman politician Marcus Tullius Cicero coined the phrase Ipse dixit, which translates from the Latin as "He, himself, said it."
The Roman politician Marcus Tullius Cicero coined the phrase Ipse dixit, which translates from the Latin as “He, himself, said it.”

 The Step Stool, the fall and the lawsuit in New Mexico

Suzanne R. Heer bought Rubbermaid step stool that she purchased at Costco and that Tricam Industries designed and manufactured. While using it, she fell and broke her arm and eventually brought a suit for product liability among other claims.

To establish the cause of fall, she retained Bradley J. Stolz, a mechanical engineer with a masters degree. The Court noted that before this case, Mr. Stolz had deposed in three other cases, all involving motor vehicle accidents. For the purpose of this case, Mr. Stolz conducted a laboratory examination on the step stool which, the court noted, consisted solely of Mr. Stolz’s observations and measurements of the step stool. 

Based on his examination and his review of Ms. Heer’s deposition testimony, Mr. Stolz concluded with “a reasonable degree of engineering certainty” that Ms. Heer’s fall was not the result of misuse or failure to follow warnings, but instead was due to a defect in the design of the step stool’s leg.

The Defendants moved to exclude his testimony and challenged both his qualifications as well as the methodology. The District Court found him to be qualified to testify but found problems with his methodology.  Specifically, the district court noted:

  1. his testimony was not scientific and did not “draw on any specialized knowledge or utilize any discernable methodology
  2. he did not test his hypothesis of the cause of the fall or his alternative design for the stool
  3. he relied only on a visual inspection of the step stool, some measurements, and a review of Ms. Heer’s deposition testimony
  4. his report did not refer to the ANSI safety standards for ladders; and
  5. he failed to eliminate as a plausible cause for the step stool’s collapse that Ms. Heer lost her balance while reaching for the vent, causing her to fall and to collide with the step stool as she landed.

Based on these observations, the District Court granted the motion to exclude Stolz’s testimony. Since there was no other way for the Plaintiff to establish a design effect, the Defendant’s motion for summary judgment was also granted.

On appeal, the 10th Circuit noted that the record in this case was replete with the district court’s analysis and careful application of the Rule 702 and Daubert factors. In a ten-page memorandum decision, the district court thoroughly evaluated Mr. Stolz’s report, applied the Daubert factors to his methodology, and provided abundant support for its decision to exclude his testimony.

While noting that the exclusion of expert testimony is the exception rather than the rule, the 10th Circuit observed that a district court may properly exclude such testimony when the opinion evidence “is connected to existing data only by the ipse dixit of the expert” such that “there is simply too great an analytical gap between the data and the opinion offered. [Quoting Joiner v. General Electric 522 U.S. 136, 146]

The 10th Circuit held that the expert report provided no scientific basis for its conclusion that a defect in the step stool’s design caused Ms. Heer’s fall. Mr. Stolz made no attempt to test his theory, nor did he make any calculations, apply any engineering principles to his causation theory, discuss any industry standards, or mention any scientific authority that supported his theory. Without scientific or technical support for Mr. Stolz’s theory, the district court was left with only Mr. Stolz’s conclusory opinion that the step stool was defective. Such an unsubstantiated basis is insufficient under Rule 702, and the district court was therefore within its discretion in determining Mr. Stolz’s opinion was not reliable.

The decision of the district court was affirmed.

You can read the full opinion of the 10th circuit here. Do you agree that experts should always make sure that their reports and methodologies are unquestionable or else it would be a great disservice to their client as well as a great threat to their future as an expert witness? What are the best practices you follow as an expert witness when writing your report? Share your experiences and tips with fellow experts in the comments section below. You can now comment using your Facebook, Twitter or LinkedIn accounts as well.

Read how the 9th circuit had recently reversed the decision of the district court to exclude expert testimony and grant summary judgment in another products liability case.