Welcome to the Substantial Similarity guide from the University of Michigan Library Copyright Office.
This guide focuses on the copyright doctrine of substantial similarity. Substantial similarity is a level of similarity that shows improper appropriation of the plaintiff’s work, one of the requirements for a prima facie infringement claim. If the similarity of the defendant’s work to protectable elements in the plaintiff’s work is minimal, or if similarity only exists with regard to unprotectable elements of the work, then there is no substantial similarity. For an introduction to copyright, please see our guide to Copyright Basics.
The guide contains summaries of the following cases, along with a glossary of key terms:
The case summaries and glossary were initially written by research assistant Yuanxiao Xu. Quotes within the summaries are from the case summarized, unless otherwise noted. This guide was last revised on February 9, 2018.