A district judge in Texas admitted the testimony of an industrial engineering and workplace ergonomics expert in order to get a better sense of the lifting activities performed by the Plaintiff on the date of her alleged injury.
Plaintiff (“Yoakum”) filed this personal injury lawsuit against Tyson after an injury she allegedly sustained while working the night shift at the Tyson Foods beef processing plant in Amarillo, Texas. Yoakum’s alleged injuries stemmed from her lifting a 97-pound box of meat off a conveyor belt to place it onto a pallet. When Yoakum lifted the box to place it onto the pallet, she alleged that she felt a pop in her back that was accompanied by pain.
On October 20, 2023, Yoakum served on Tyson the expert reports of her retained experts, which included Adam W. Pickens, P.h.D—whom she retained to opine on lifting safety and the risks associated with her lifting the 97-pound box. Pickens opined that Yoakum lifting a 97-pound box created a high risk of injury. His opinion relied on two tools that are not adopted by any industry, including the meatpacking industry: (1) the NIOSH Lifting Equation (“the Lifting Equation”) and (2) the Liberty Mutual Psychophysical Tables (“the Liberty Mutual Tables”).
Industrial Engineering Expert Witness
Adam W. Pickens is an expert in industrial engineering and workplace ergonomics. He holds a Bachelor’s degree in Biomedical Sciences and a Master’s of Public Health in Environmental and Occupational Health from Texas A&M University. He holds a Ph.D. in Industrial Engineering from Texas Tech University in Lubbock, Texas. Pickens worked as a graduate researcher and in industry for Alliant Techsystems. He was a NIOSH trainee and served as a scientific review expert for them for over 10 years. Since 2008 he has been on the faculty of Texas A&M University in the School of Public Health.
Discussion by the Court
Tyson’s motion to exclude Pickens is focused on three arguments. First, Tyson argued that Pickens’ use of the Lifting Equation is inadequate and unreliable because he did not input values and “actually run” the Lifting Equation. Second, Tyson argued that neither the Lifting Equation, nor the Liberty Mutual Tables have been accepted in the meatpacking industry—or any industry—as the industry standard. Third, Tyson argued that Pickens’ opinion was unnecessary to assist the jury in understanding the evidence or answering any fact questions in the case because he failed to address key facts and circumstances of the case.
A. Pickens’ testimony is based upon sufficient facts and data
The Court observed that Pickens reviewed relevant filings on the docket, Yoakum’s employment files, Tyson’s “Safe Lifting Training” and “Lifting Do’s and Don’ts”, the depositions of Yoakum and her coworkers, and Pickens was provided with the weight of the box Yoakum was lifting when she allegedly injured her back.
He relied on two foundational works/tools: the NIOSH Lifting Equation—which has been accepted as reliable by several federal courts—and the Liberty Mutual Psychophysical Tables.
The Court noted Pickens’ substantial experience as an expert in workplace ergonomics and his experience as a NIOSH Trainee, for which he has served as a scientific review expert for over 10 years. Pickens also relied upon scientific literature and industry materials to use his expertise to form an opinion on Yoakum’s lifting task in this case.
The Court found the facts and data Pickens relied upon to be sufficient and of the type reasonably relied upon by experts in the field of biomechanics, ergonomics, and workplace safety.
B. Pickens’ testimony is the product of reliable principles and methods, and Pickens applied those principles and methods reliably to the facts of the case
1. NIOSH Lifting Equation
Pickens’ testimony relied in part on the NIOSH Lifting Equation. The Lifting Equation is a tool used to estimate safe lifting limits for the average adult in the workplace. Specifically, the Lifting Equation was developed by NIOSH to quantify injury risks associated with manual lifting. The Lifting Equation consists of a load constant (51 pounds) that is then multiplied by six variables that only serve to decrease the load constant. In other words, regardless of the values input into the variables, the highest output the Lifting Equation will ever produce is 51 pounds.
The Court found that the Daubert factors suggested that the Lifting Equation is sufficiently reliable to form the basis of expert testimony.
As to the first factor, the NIOSH Lifting Equation can be and has been tested. Likewise, the Lifting Equation has been subjected to peer review and publication; thus, the second factor is met. As to the fourth factor, the NIOSH Lifting Equation appears to be accepted in the field of ergonomics and workplace safety. Pickens acknowledged that the NIOSH Lifting Equation has not been explicitly adopted by any industries, including the meatpacking industry, but that it is applicable to the work force at large. The fifth factor is also satisfied as there is no evidence whatsoever that the NIOSH Lifting Equation was developed expressly for litigation. As to the sixth factor, Pickens did not unjustifiably extrapolate from an accepted premise to an unfounded conclusion. Finally, the field of ergonomics is known to reach reliable results.
In sum, the enumerated Daubert factors are largely applicable in this situation and weigh in favor of admitting Pickens’ expert testimony.
2. Liberty Mutual Psychophysical Tables
Not dissimilar from the Lifting Equation, the Liberty Mutual Tables are a tool that Pickens used that led him to his conclusion that the box Yoakum lifted in this case exceeded the safe limit under all circumstances. According to Pickens, the Liberty Mutual Tables indicated that no female can safely lift a 97-pound box during a workday without risk of injury. Like the 51-pound limit in the Lifting Equation, the Liberty Mutual Tables established that a woman should never, under any circumstances, lift more than 83.6 pounds during a workday without risk of injury.
The Liberty Mutual Tables, developed by Liberty Mutual Insurance, covered tasks such as lifting, lowering, pushing, or pulling. According to Pickens and his references, the Liberty Mutual Tables are the product of more than 40 years of research on lifting, lowering, pushing, pulling, and carrying and have been subjected to peer review and publication. Accordingly, the Court found that the Liberty Mutual Tables are reliable in and of themselves.
Likewise, Pickens reliably applied the facts of this case to the Liberty Mutual Tables to form his opinions. As noted, he reviewed the litigation file, relevant documents, and was provided with the fact that the box Yoakum lifted when she allegedly injured her back was 97 pounds. The Court held that Pickens reliably applied the facts of this case to the Liberty Mutual Tables to form his opinion that Yoakum could not have lifted the 97-pound box at issue without facing a risk of injury.
C. Pickens’ opinions are relevant
The relevance inquiry requires the Court to consider whether the opinions of Pickens will assist the jury in understanding the evidence or answering fact questions.
Liability in this case is dependent upon a finding of negligence; therefore, the issue before the Court is whether Pickens’ testimony will aid the jury in determining negligence. The Court found that Pickens’ testimony is sufficiently relevant and will assist the jury in understanding the lifting activities performed by Yoakum on the date of her alleged injury. In sum, Pickens’ testimony may inform the determination of whether Tyson was negligent.
D. Tyson’s criticisms of Pickens’ opinions are topics for cross-examination, not a basis for exclusion
Tyson took issue with numerous aspects of Pickens’ testimony. But the aspect that Tyson focused on most is that Pickens did not input values into the Lifting Equation to calculate a Lifting Index.
First, when asked why he “did not run” the Lifting Equation, Pickens testified that he did not have the information to input values into the variables and calculate a Lifting Index. Ultimately, Pickens concluded it is irrelevant that he did not input values into the equation and calculate a Lifting Index because the maximum weight the Lifting Equation called for without a risk of injury is 51 pounds. And in this instance, Yoakum allegedly lifted a 97-pound box, so there was no need for Pickens to run the equation. This is because no matter what values he put into the Lifting Equation, the highest possible output value would be 51 pounds; thus, Pickens’ conclusion would remain the same.
The Court found that the best mechanism for Tyson to attack Pickens’ testimony was through cross-examination, not exclusion.
E. The Lifting Equation and the Liberty Mutual Tables cannot establish the standard of care; however, the tools will assist the jury in understanding the lifting activities performed by Yoakum on the date of her alleged injury
The Lifting Equation and the Liberty Mutual Tables are not adopted by any industry as industry standards. As such, the Court agrees with Tyson that neither the Lifting Equation nor the Liberty Mutual Tables can take the place of the applicable standard of care.
Because neither the Lifting Equation nor the Liberty Mutual Tables have been accepted by any industry, including the meatpacking industry, Yoakum cannot rely on either tool to establish the standard of care in this case. And the Court will refuse to allow testimony from Pickens to that effect. However, given his expertise, the tools he used, and his reliable application of the facts of this case, the Court permitted Pickens to testify that Yoakum faced a risk of injury when she was asked to manually lift the 97-pound box.
The Court held that Pickens’ testimony may rely on his application of the facts of this case to both tools he chose to utilize, but his testimony cannot establish Tyson breached its standard of care based solely on Yoakum having lifted a 97-pound box.
Held
The Court found the facts and data Pickens relied upon to be sufficient and of the type reasonably relied upon by experts in the field of biomechanics, ergonomics, and workplace safety. Moreover, the Court was confident that any issues Tyson had with Pickens’ methodology and opinions could be addressed on cross-examination.
The Court denied Tyson’s motion to exclude the testimony of Adam W. Pickens.
Key Takeaways:
- Pickens reliably applied the facts of this case to the Liberty Mutual Tables to form his opinion that Yoakum could not have lifted the 97-pound box at issue without facing a risk of injury. Pickens reviewed the litigation file, relevant documents, and was provided with the fact that the box Yoakum lifted when she allegedly injured her back was 97 pounds.
- Pickens’ testimony satisfied the relevance inquiry under Daubert because it assisted the jury in understanding the lifting activities performed by Yoakum on the date of her alleged injury.
- Considering there are no certainties in science, the Court decided that should Tyson wish to challenge any shortcomings in Pickens’ methodology or his application of the facts to either the Lifting Equation or the Liberty Mutual Tables, it may do so through cross-examination.
Case Details:
| Case Caption: | Yoakum v. Tyson Foods Inc. |
| Docket Number: | 2:22cv239 |
| Court: | United States District Court, Texas Northern |
| Order Date: | May 21, 2024 |
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