Eveready Factors – Likelihood of Confusion Survey

Confusion Factors Tested by Eveready

The Eveready format primarily addresses three confusion factors:

  • similarity of marks,
  • similarity of products, and
  • brand strength (accessibility in memory)

Strength is the key. If a schema is easily accessible in the mind of a consumer, it can be cued by a similar mark even where there is little or no similarity in products. And, if a brand is dominant (e.g. COKE), its schema may be cued by another brand in the category (e.g. PEPSI), even where there is no similarity of marks.

If, however, the senior mark is not accessible, it obviously cannot be cued irrespective of mark and product similarity. When an”open­ end question is used in connection with a mark that is not particularly well-known, it needs to be understood that the “top-of-mind” awareness of the brand required by the Eveready format may significantly underestimate the likelihood of confusion.

The Scope of Eveready

In cases involving strong marks, the Eveready format is the gold standard for fundamental cognitive and marketing reasons.

An Eveready survey used among prospective consumers of the alleged infringer’s products or services, with the stimulus left in view, engenders respondent attention approximating that of an involved consumer and thus produces, coupled with a control cell to filter market-share effects, a reliable estimate of likelihood of confusion.

Reviews of “why” question answers typically reveal that senior mark responses to a “who makes or puts out” question have occurred because the “stored knowledge” of the senior mark is “accessible” in a respondent’s memory and there is a fit between the stored knowledge and the junior mark. Accordingly, an expert’s conclusion as to a “likelihood of confusion,” based on an appreciable percentage of senior mark responses, has cognitively sound underpinnings. 

Because a strong mark is likely to be attended to in the marketplace, it is reasonable to assume that a stimulus that “fits” the strong mark’s schema will be attended to, and that an Eveready survey thus measures probable assessments in the marketplace, not artificially created or forced opportunities.

The only hypothetical is the degree to which a respondent would be likely to encounter the junior use in the marketplace, and any concern as to the real world basis for that likelihood is alleviated by limiting the universe to consumers and prospective consumers of goods in the category of the alleged.

With  respect to strong marks, therefore, the Eveready format is a relevant, reliable, and objective test of likelihood of confusion. It is a peer reviewed tested approach and has been generally accepted in the scientific community.


  • A mark that is strong…is more likely to be remembered and more likely to be associated in the public mind with [or triggered by] a greater breadth of products . . ., than is a mark that is weak because relatively unknown ” James Burrough ltd.,540 F.2d at276.
  • William G. Barber discusses this phenomenon in a dilution context in  Howto Do a Trademark Dilution Survey (or Perhaps How Not to Do One), 89 TRADEMARK REP. 616 (I 999). Control cells are thus necessary in any consumer survey as to strong marks. See Jerre Swann, Dilution Redefined for the Year 2002, 92 TRADEMARK REP. 585, 619-20(2002).
  • PHYLLIS WELTER,TRADEMARK SURVEYS§24.03[I][c](1999).Welter postulates that the Eveready format requires”unaided awareness” of the senior brand. In our view, however, the format more closely resembles a partially aided awareness test: it assesses whether the junior user’s mark and product cues are similar enough to those of the senior brand to trigger the latter ‘s schema in response to a source confusion question.
  • Jerre B. Swann, Sophistication and the Sciences, 97 TRADEMARK 1309 (2007). It is our view that net confusion from an Eveready of less than 10% should suffice to support a conclusion as to likelihood of confusion (and that, because of  an  elevated degree of  noise discussed below, a net level above 10% should be required from a  Squirt  format). See McCARTHY,  supra  note5,  § 32: 189  (discussing  a 10% threshold).
  • See Tory Higgins, Knowledge Activation: Accessibility, Applicability,  and Salience, in SOCIAL PSYCHOLOGY: HANDBOOK OF BASIC PRINCIPLES135 (Guilford Press 2007); Michel Tuan Pham & Gita V. John r, Contingent Processes of Source Identification, 24 J. of CONSUMER RESEARCH249, 250 (1997) (“The probability of source identification through cued retrieval depends essentially on [a.] the strength of the semantic link between the source and content that is formed at encoding, and [b.J the overlap between the cues that are available at retrieval, and the to-be-recollected material “). With ADIDAS, for example, most respondents give”stripes” in answer to a “why” question, reflecting their access to the three stripe mark and the ” fit” or “overlap” with a stimulus that merely adds one stripe, or takes one stripe away.

Rhonda Harper – Expert Witness

Rhonda Harper is routinely retained to formulate expert surveys, conduct rebuttal critiques, or construct rebuttal surveys to show the potential difference in results with properly designed and executed surveys.

Rhonda Harper has extensive experience and a deep understanding of survey design, sampling, question construction, data analysis, and methodological pitfalls that introduce bias or systematic error. Harper also provides guidance on how to approach the opposing expert’s deposition.   

About Rhonda Harper LLC – Expert Witness

Located in Dallas, TX, Rhonda Harper has been retained by 95+ law firms since 2005. With a focus on Trademark and Trade Dress Infringement, Misleading and Deceptive Advertising, Licensing, and Commercial Reasonableness cases, Rhonda Harper has conducted hundreds of research studies, including 50+ Likelihood of Confusion and Secondary Meaning surveys. She has been deposed ~50 times and served in ~20+ trials and arbitrations.

For more information, call Rhonda Harper at 214-244-4608.