The overall purpose of trademark law is to avoid any consumer confusing the source of one product, with the source of another product. The Lanham Act prohibits the registration of use of a trademark if that mark is likely to cause confusion. In each application before the USPTO, the examining attorney must only consider the facts of the application in front of him. Prior trademark decisions and other products have little to no impact on the determination.

The USPTO emphasizes that usually, no single factor will determine whether consumers will be likely to be confused. The factors are looked at as a whole. Some factors may be given more or less weight than others in any given situation. The Trademark Trial and Appeal Board follow what is know as the “du Pont” factors when determining likelihood of confusion. The du Pont factors are:

  • The similarity or dissimilarity of the marks in their entireties as to appearance, sound, connotation and commercial impression;
  • The similarity or dissimilarity and nature of the goods or services as described in an application or registration or in connection with which a prior mark is in use;
  • The similarity or dissimilarity of established, likely to continue trade channels;
  • The conditions under which and buyers to whom sales are made, i.e. “impulse” vs. careful, sophisticated purchasing;
  • The fame of the prior mark (sales, advertising, length of use);
  • The number and nature of similar marks in use on similar goods;
  • The nature and extent of any actual confusion;
  • The length of time during and conditions under which there has been concurrent use without evidence of actual confusion;
  • The variety of goods on which a mark is or is not used (house mark, “family” mark, product mark);
  • The market interface between the applicant and the owner of a prior mark: a mere “consent” to register or use, agreement provisions designed to preclude confusion, i.e. limitations on continued use of the marks by each party, assignment of mark, application, registration and good will of the related business, laches and estoppel attributable to owner of prior mark and indicative lack of confusion;
  • The extent to which applicant has a right to exclude others from use of its mark on its goods;
  • The extent of potential confusion, i.e., whether de minimis or substantial; and
  • Any other established fact probative of the effect of use.