Expert Witness Blog

In the recent case of Dynamite Marketing, Inc. v. The WowLine, Inc., No. 24-1523 (Fed. Cir. 2025), the United States Court of Appeals for the Federal Circuit addressed the admissibility and impact of testimony from a Marketing Expert Witness in a complex patent infringement litigation. The case provides a clear illustration of how federal courts scrutinize expert witness qualifications and methodologies under Daubert, particularly in the context of lost profits damages.

Background and Parties

Dynamite Marketing, Inc. (“Dynamite”) brought suit against The WowLine, Inc. (“Sherman”) alleging infringement of a design patent. The dispute centered on whether Sherman’s product infringed Dynamite’s patent and, if so, the appropriate measure of damages. Dynamite sought lost profits under 35 U.S.C. § 284, while Sherman contended that its own profits from the alleged infringement should serve as the damages benchmark.

In the case of In re: Paraquat Products Liability Litigation, MDL No. 3004 (S.D. Ill. 2024), the United States District Court for the Southern District of Illinois addressed the admissibility of expert testimony in a multidistrict litigation (MDL) concerning allegations that exposure to the herbicide paraquat caused plaintiffs to develop Parkinson’s disease. The involvement of a Products Liability Expert Witness was central to the court’s analysis.

Case Background

Paraquat is a widely used herbicide in the United States, primarily applied for weed and grass control. Plaintiffs in this MDL alleged that exposure to paraquat, manufactured by Syngenta and distributed by Chevron, led to the development of Parkinson’s disease. They claimed that the defendants failed to warn users about the potential neurological risks associated with paraquat exposure.

n the case of Marimuthu v. Signal International, No. 1:13-cv-00498 (E.D. Tex. 2015), the United States District Court for the Eastern District of Texas addressed the admissibility of expert testimony in a lawsuit involving allegations of human trafficking and substandard living conditions. The testimony of an OSHA Expert Witness was central to the court’s analysis.

Case Background

Following Hurricane Katrina, approximately 590 individuals, including the plaintiffs in this case, were allegedly trafficked to the United States to provide labor for Signal International, a marine construction company. The plaintiffs claimed they were lured with promises of good pay and permanent residency but were instead subjected to inhumane conditions in overcrowded labor camps. They alleged that the camps were unhygienic, disease-ridden, and resembled prisons, forcing them to continue working under threat of significant debts and fears of deportation.

In the case of Morris v. Harley-Davidson Motor Company, a jury awarded $287 million to Harold Morris, a 79-year-old Navy veteran, following a tragic accident involving a Harley-Davidson trike motorcycle. The testimony of a Motorcycles Expert Witness played a pivotal role in this litigation.

Case Background

In 2020, Harold Morris was operating his Harley-Davidson trike with his partner, Pamela SinClair, as a passenger. During their ride, the trike unexpectedly experienced braking issues, leading to a severe crash that resulted in SinClair’s death and left Morris with life-threatening injuries. Notably, Morris had encountered a similar incident in 2019, where the trike exhibited sudden braking problems. After the initial incident, he sought service from a Harley-Davidson dealership, which assured him that the motorcycle was safe to operate.

n the case of Baker v. Blackhawk Mining, LLC, Civil Action No. 5:22-231-DCR (E.D. Ky. 2023), the United States District Court for the Eastern District of Kentucky addressed the admissibility of expert testimony in a lawsuit concerning environmental contamination allegedly resulting from mining activities. The involvement of a Mining Expert Witness was central to the court’s analysis.

Case Background

Plaintiff David Baker filed a lawsuit against Blackhawk Mining, LLC, alleging that the company’s mining operations led to the contamination of his property. Baker claimed that pollutants from Blackhawk’s mining activities had migrated onto his land, causing environmental damage and diminishing the property’s value. He sought damages for negligence, trespass, and nuisance, asserting that Blackhawk failed to implement adequate measures to prevent the spread of contaminants.

In the case of Everson v. Nautilus Insurance Co., No. 2:23-cv-1360 (E.D. La. Sept. 16, 2024), the United States District Court for the Eastern District of Louisiana addressed the admissibility of expert testimony in a negligence lawsuit involving a tree-cutting incident. The involvement of a Tree/Arborist Expert Witness was central to the court’s analysis.

Case Background

On December 9, 2021, plaintiff Darryl Everson was driving in Montz, Louisiana, when a tree felled by defendant David Rugg allegedly struck his vehicle, causing injuries to his back and neck. Everson claimed that Rugg, employed by Romesberg Trucking Inc. (RTI) and insured by Nautilus Insurance Company, negligently conducted tree-cutting activities near the roadway. Specifically, Everson alleged that the defendants failed to provide adequate warnings, monitor approaching vehicles, and properly train Rugg, thereby creating a hazardous situation.

In the case of Lehmann v. Louisville Ladder Inc., 610 F. Supp. 3d 667 (E.D. Pa. 2022), the United States District Court for the Eastern District of Pennsylvania addressed critical issues concerning product liability and the admissibility of expert testimony in a lawsuit stemming from a scaffold-related injury. The involvement of a Ladders & Scaffolds Expert Witness was central to the court’s analysis.

Case Background

Plaintiff Michael Lehmann sustained injuries after falling from a scaffold manufactured by Louisville Ladder Inc. He filed a lawsuit alleging that the scaffold was defectively designed and lacked adequate warnings, leading to his accident and subsequent injuries. Lehmann’s claims were grounded in theories of strict liability and negligence, asserting that the design flaws and insufficient warnings rendered the scaffold unreasonably dangerous for users.

In the landmark case of Jones v. Kaney, [2011] UKSC 13, the United Kingdom Supreme Court addressed the issue of whether expert witnesses could be held liable for professional negligence in relation to their participation in legal proceedings. This case significantly impacted the legal landscape concerning the accountability of expert witnesses, including those specializing in personal injury cases.

Case Background

In 2001, Paul Wynne Jones was involved in a road traffic accident and subsequently pursued a personal injury claim, alleging both physical and psychological harm. His legal team engaged Dr. Sue Kaney, a consultant clinical psychologist, to provide expert testimony supporting his claim of post-traumatic stress disorder (PTSD). Initially, Dr. Kaney’s assessment aligned with Jones’s assertions.

In the case of Bray v. Bi-State Development Corporation, 949 S.W.2d 93 (Mo. Ct. App. 1997), the Missouri Court of Appeals addressed the admissibility of expert testimony concerning lighting conditions in a premises liability lawsuit. The involvement of a Lighting & Illumination Expert Witness was central to the court’s analysis.

Case Background

The plaintiff, Bray, sustained injuries after tripping over a curb in a parking garage operated by Bi-State Development Corporation. She alleged that inadequate lighting contributed to her fall and filed a negligence claim against the defendant. The defense contended that the lighting was sufficient and that Bray’s negligence was the sole cause of her injuries.

In the case of Ruth Mitchell v. City of Franklin, Tennessee, No. M2021-00877-COA-R3-CV (Tenn. Ct. App. May 25, 2022), the Tennessee Court of Appeals examined the admissibility and impact of expert testimony in a premises liability lawsuit. The involvement of a Human Factors Expert Witness was central to the court’s analysis.

Case Background

Ruth Mitchell, the plaintiff, filed a lawsuit against the City of Franklin, Tennessee, after tripping over a temporary sign base on a sidewalk and sustaining injuries. She alleged that the City was negligent in maintaining the sidewalk and failing to warn pedestrians of the hazard. The City denied liability, contending that the sign base was open and obvious, and that Mitchell was at fault for not paying attention.