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Fair Use: Factor 3: Substantiality

In some cases, I don’t actually need to ask for permission to use others’ content?!

Factor 3: Substantiality of the Portion Used

The amount and substantiality of the portion used in relation to the copyrighted work as a whole;

Fair use consideration is judged in a primarily qualitative rather than quantitative method, so specific content limitations on the amount used is not precise. Generally, the less used the more likely it can be counted for fair use. Also, consider the portion amount in proportion to the total amount.

Tips and core concepts:

  • The “heart” of the work--the core, representative point of the work--may not be considered fair use because it is the most valuable part of the work. It should not be able to substitute for the point of the original content
  • A small portion could be considered more safely in total of approximately less than 400 words or 2% of a book (whichever is less), or 150 words or 7% of an article (whichever is less).
  • When considering fair use, all content from a single source is considered as a total sum (rather than within individual excerpts) in this proportion of substantiality
  • Images are harder to consider for fair use because using an image is the entirety of that work
  • Using content as a standalone object, like an epigraph, in your work is unlikely to be considered for fair use, as you are not adding anything of value to that content. You’re using it merely as an extra color rather than as a component of critical discussion.

Example: Posted Chapter for Class


Professor Chen is teaching an online course titled Frontiers in Biotechnology. This week's topic concerns the use of genetic information in the context of personalized medicine. Professor Chen would like students to read this article:

Gholson J. Lyon, "Personalized medicine: Bring clinical standards to human-genetics research." Nature 482 (16 February 2012): 300-301. doi:10.1038/482300a.

Professor Chen downloads the article PDF and posts it to Sakai for students to read. Is this fair use?


Professor Chen does not need to rely on fair use in this case because the University X has a site license to Nature online that allows the university to make the licensed content available to authorized users for the purposes of research, teaching, and private study. This includes the right to reproduce individual articles for distribution to students as course readings and to create hypertext links to the licensed content as long as access is restricted to authorized users. Authorized users are defined as faculty, staff, enrolled students, and walk-in users of the library.