Likelihood of consumer confusion is the touchstone of trademark law and determining whether there is infringement, which is the unauthorized use of a mark on or in connection with goods and/or services in a manner that is likely to cause confusion, deception, or mistake about the source or sponsorship of the goods and/or services. Whether there is a likelihood of confusion is assessed by considering a number of factors, which vary jurisdiction by jurisdiction. Below we discuss the factors evaluated by the Ninth Circuit:

Similarity of the Marks: Confusion may arise primarily as a result of the mental associations conjured by the appearance of two marks, considering the marks in terms of sight, sound, and commercial meaning.

Sight – the visual impression created by the mark as a whole. Consumers generally have imperfect memories and changing one or two letters in a mark generally will not avoid a likelihood of confusion. Further, where the mark is comprised of multiple terms, the dominant feature, often the most distinctive term of the mark, is entitled to more weight.

Sound – the similarities in pronunciation. This is particularly important where brands are often verbally discussed. We note that the correct pronunciation is not the issue, but whether purchasers pronounce the word in the same or a similar manner.

Meaning – the closeness of the commonly understood meaning or dictionary definitions of the marks.

Strength of Mark: All trademarks are not created equal; some marks are more distinctive than others. Marks can be strong or weak. Made-up (fanciful) marks like Exxon® and Kodak®, and arbitrary marks, such as Apple®, are the strongest. Arbitrary means that the term is an actual word but that word is used as a mark in connection with a good/service that is entirely unrelated to the generic meaning of the word. Suggestive marks, e.g., Microsoft®, Chicken of the Sea®, and Coppertone®, that don’t actually communicate anything directly about the product, are the next strongest.

A mark is not distinctive if it is merely descriptive, that is it describes an ingredient, quality, characteristic, function, feature, purpose, or use of the specified goods or services. Merely descriptive marks, e.g., Little Tavern™ for a restaurant or MultiAccount™ for debit cards, that immediately communicate something about a feature or attribute of a product are considered weak, and are considered intrinsically weak and are entitled to only a narrow scope of protection against uses of similar marks.

Similarity of Goods/Services: The likelihood of confusion occurring is typically enhanced where goods/services sold under the same or similar marks are identical or closely related. This presumption is founded on an empirical, or perhaps a psychological, premise, namely, that consumers have been conditioned to assume that manufacturers and merchants usually manufacture and market their goods and services within related fields. Thus, courts assume that it is reasonable and likely for consumers to believe that if similar marks are applied to similar goods or services they probably come from the same, or a related, source. Keep in mind, the goods and services do not have to be identical, only arguably related, which could encompass complementary goods, similarity of use, etc.

Evidence of Actual Confusion: While proof of actual confusion is not required to providing likelihood of confusion, if such evidence exists it is given significant weight. The treatment of actual confusion evidence varies depending on the particular circumstances. For example, one or two instances of actual confusion where the marks have been coexisting for multiple years is less probative than if the marks have only been coexisting for a few months. It is important to note that “inquiry confusion,” i.e., purchasers inquiring whether two brands are related, does not necessarily constitute actual confusion when the purchasers are aware that two brands exist and are merely inquiring about the relationship.

Marketing Channels: The “marketplace” environment in which marks are actually and usually encountered by the purchasing public is an important factor that may contribute to (or detract from) a likelihood of confusion. Where goods are sold through the same channels of trade, or in the same store or specialty shop, likelihood of confusion is enhanced because purchasers are mentally conditioned toward assuming a single source. Nowadays, most businesses promote and sell their products, or otherwise have some presence, on the Internet, but this does not automatically mean that they are sold through the same channels of trade. In assessing the similarity of online channels, the initial inquiry is whether consumers would likely come across both party’s marks while online.

Degree of Care/Sophistication: Care while making a purchase can affect whether confusion is likely. Purchasers typically exercise a high degree of care in connection with expensive items/services or items/services that have an impact on their lives, e.g., health care. When a high degree of care is exercised, purchasers are less likely to be confused due time spent considering the respective brands to make an informed decision. In contrast, when consumers do not exercise a significant degree of care, such as on impulse purchases or relatively inexpensive items, the potential for likelihood of confusion can be heightened.

Junior User’s Intent in Selecting the Mark: If it is found that the junior user adopted a mark in “bad faith,” or even with some prior knowledge of the senior user’s brand, the senior user’s case for infringement can be more favorably considered.

Likelihood of Product Line Expansion: Another consideration is the senior user’s trademark rights in the mark owners “natural area of expansion.” Some courts examine this under the framework of the senior user’s business interest in preserving avenues of expansion and entering into related fields. Other courts look at it as a question of the relatively likelihood that a senior user would enter into a different product market currently occupied by a junior user.

Assessing likelihood of confusion is a balance of all these factors, and no one factor is dispositive; an assessment of infringement is rarely black or white. Evaluating whether there is a likelihood of confusion between two marks is extremely fact specific and requires an understanding of a long history of nuanced trademark law precedent.