There Is No Such Thing As a "15% Rule"
It’s almost a time-honored tradition in American prep sports: the local high school needs a logo for its football team, adopts the mark of a well-known college program, changes it by "15%," and voila, they now have a "new" logo to call their own.
The idea that altering a college logo by “15%” (or 10%, 40%, or whatever) as a means of protecting a high school from legal action is widespread as an understood fact. It is, however, a bogus concept.
In general, the standard for trademark infringement is whether a design is “confusingly similar” to a protected mark. An infringing trademark does not need to be exactly identical to a protected trademark, but may instead be determined as likely to cause confusion as to source, licensing, approval, etc..
Rights to a protected mark can also be violated by “dilution” – either by tarnishment or blurring of the strength and distinctiveness of the mark.
Additionally, college logos are subject to copyright protection. Use of a protected college logo by a high school could therefore also give rise to a claim of copyright infringement.
When a college enforces its rights in its logo, it generally does so by these three standards, not by an arbitrary “15% different” determination.
In the social media-driven internet age of today, high school athletic brands are more powerful than administrators realize. Investing in a legally trademark-able athletics identity is the first step to realizing benefits that can impact an entire school.
My thanks to Jim Aronowitz for his help in understanding and explaining this legal issue.