Expert Testimony on Legitimate Marketing Practices Admitted
Posted on August 21, 2025 by Expert Witness Profiler
The Federal Trade Commission contended that Amazon tricked, coerced, and manipulated consumers into subscribing to Amazon Prime. According to the FTC, this was accomplished by failing to disclose the material terms of the subscription clearly and conspicuously and by failing to obtain the consumers’ informed consent before enrolling them. The FTC also alleged that Amazon did not provide simple mechanisms for subscribers to cancel their Prime memberships. The FTC sued Amazon.com, Inc. and three of the company’s executives, Neil Lindsay, Russell Grandinetti, and Jamil Ghani.
Defendants’ expert Donna L. Hoffman, Ph.D. offered five opinions. First, she said that analysis of online consumer experience must account for consumers’ goals, past experiences, and expectations. Second, she said that the definition of “dark patterns” is vague and lacks scholarly consensus. She also said that the subjective interpretation of this term may misidentify common legitimate marketing practices as “dark patterns.” Third, she said that the FTC’s claims regarding the user interface (“UI”) design elements in Amazon Prime Enrollment and Cancellation Flows are “unfounded.” Fourth, she said that the UI design elements at issue are common online and likely familiar to consumers. Fifth, she said that Amazon’s clarity improvement initiatives had methodological limitations that limited Amazon’s ability to interpret the results.
The FTC made two primary arguments to exclude Hoffman’s testimony. First, it said that her analysis of the Prime Enrollment and Cancellation Flows is irrelevant and unreliable. Second, it said that her comparative analyses of UI elements is similarly irrelevant and unreliable.
Marketing Expert Witness
Donna L. Hoffman, Ph.D., is a marketing professor at The George Washington University School of Business. She has a Ph.D. from the University of North Carolina at Chapel Hill and her training is in psychometrics, a field of behavior science that focuses on experimental design and human cognition and behavior.
Her work has been published in all of the field’s top journals and enjoys wide impact with nearly 30,000 Google scholar citations.
Hoffman has been awarded many of the field’s most prestigious awards, including being named a Fellow of the Society for Consumer Psychology, the Robert B. Clarke Educator of the Year Award from the DMEF, the Sheth Foundation/Journal of Marketing Award for long-term contributions to the discipline of marketing, the Stellner Distinguished Scholar Award from the University of Illinois, the William O’Dell/Journal of Marketing Research Award for long-term research impact, and others.
Discussion by the Court
A. Relevance of Hoffman’s Testimony
1. Analysis of Prime Enrollment and Cancellation Flows
The FTC argued that Hoffman’s analysis of the Prime Enrollment and Cancellation Flows is irrelevant. It said that this analysis is irrelevant because it will not help the factfinder determine whether Amazon disclosed Prime’s terms clearly and conspicuously, obtained informed consent from Prime subscribers, or provided simple mechanisms to cancel Prime.
Defendants have shown by a preponderance of the evidence that the analysis is relevant. The FTC contended that Prime’s enrollment and cancellation flows include manipulative designs. And Hoffman’s analysis directly responded to this allegation by saying, among other things, “the FTC’s failure to consider consumers’ familiarity with design elements or standard marketing practices severely undermines their conclusions about whether the alleged UI design elements at issue in Amazon Prime’s enrollment and cancellation flows would ‘trick,’ ‘manipulate,’ or ‘mislead’ consumers and influence their behaviors or ‘complicate’ these processes.”
2. Comparative Analyses of UI Elements
The FTC also said that Hoffman’s comparative analyses are irrelevant because they are not focused on Prime. According to the FTC, regardless of the practices employed by other subscription services, the factfinder must evaluate Amazon’s conduct independently. But Defendants said that this testimony is relevant to the “reasonable consumer” standard.
Defendants also satisfied their burden of showing that this testimony is relevant. At a minimum, much like her analysis of the Prime enrollment and cancellation flows, Hoffman’s comparative analyses responded to the FTC’s allegation that Amazon employs manipulative designs. She presented two comparative analyses that suggest “these UI design elements at-issue (or those similar to them) are commonly used online, and many consumers are likely to be familiar with them independent of their interactions with Amazon website.”
B. Reliability of Hoffman’s Testimony
1. Analysis of Prime Enrollment and Cancellation Flows
The FTC argued that Hoffman’s analysis of the Prime enrollment and cancellations flows is unreliable. It said that she does not refer to any methodology in her report and that she suggested nine methodologies during her deposition. The FTC added that even if the Court accepted that Hoffman used a methodology, the methodology is insufficiently reliable because she never defines “legitimate marketing practice.”
Although the FTC argued that she described nine methodologies, that does not appear to be the case. Instead, she applied the “concepts and constructs from [her] discipline to evaluate the flows.” As one example of this, she evaluated allegations the FTC made about the complexity of Amazon Prime’s cancellation process.
She explained how, in her opinion, the FTC overlooked “legitimate and standard marketing practice” when making these allegations. Her report also applied pertinent academic marketing and consumer behavior literature. She used a marketing management textbook to explain the complexity of a consumer’s decision-making process.
The Court found that Hoffman relied on her education and experience to reach these conclusions. The FTC also challenged Hoffman’s failure to define “legitimate marketing practices,” but her report does provide examples that she believes fall within the ambit of this term.
2. Comparative Analyses of UI Elements
First, the FTC said it was concerned that Hoffman had developed her comparative analysis specifically for purposes of this litigation. Hoffman’s report indicated that she offered conclusions “growing naturally and directly” from her education and experience in marketing research techniques. So, on balance, the Court decided that Hoffman’s comparative analysis need not be excluded simply because she developed it for the purposes of this litigation.
Second, the FTC said that Hoffman’s methodology lacked acceptable standards. For instance, the FTC complained that Hoffman did not explain how she chose to “map” each of the UI design elements that she supplied to the independent coders. But she identified the specific paragraph of the complaint that she used to generate her description of the at-issue UI element. Hoffman adequately articulates her methodological choices and provided a foundation for the data she incorporated into her report.
Third, the FTC said that there is an analytical gap between Hoffman’s data and her conclusions. On this point, the FTC appeared to misapprehend Hoffman’s report because it does not attempt to define a specific threshold at which the prevalence of a UI design element makes it “familiar” to consumers or how familiarity with one website gives consumers familiarity with an Amazon website. To the contrary, as Hoffman explained in her deposition, her goal was to establish that certain UI elements are common across commercial and government websites, and a consumer’s familiarity with these features “could likely implicate — likely impact their, you know, understanding and their interaction behavior, and things like that.”
Finally, the FTC said that Hoffman’s methodology rests on a “shaky foundation.” Yet “shaky but admissible evidence is to be attacked by cross examination, contrary evidence, and attention to the burden of proof, not exclusion.”
Held
The Court denied the Plaintiff FTC’s motion to exclude the testimony of Defendants’ expert Donna L. Hoffman.
Key Takeaway:
When an expert in an uncertain field is extrapolating from existing data and generating novel hypotheses about complex issues, she is permitted wide latitude to offer opinions.
The Court did not deem her methods unreliable because she did not explain precisely how she got from the allegations in the complaint to the analyzed UI design element. Hoffman adequately articulates her methodological choices and provided a foundation for the data she incorporated into her report. The FTC’s other arguments criticizing Hoffman’s methodology similarly failed to persuade the Court that her report is the product of unreliable methods.
Please refer to the blogs previously published about this case:
Marketing Expert Employed Techniques Widely Accepted in Market Research Community
Human Factors Expert’s Testimony on Dark Patterns Excluded
Legal Expert Allowed to Testify Despite His Lack of Particularized Expertise
Case Details:
| Case Caption: | Federal Trade Commission V. Amazon.Com, Inc., Et Al. |
| Docket Number: | 2:23cv932 |
| Court Name: | United States District Court for the Western District of Washington |
| Order Date: | August 19, 2025 |
