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OER (Open Education Resources): OER, Open Access, ZTC & Public Domain


We hear a lot about OER (Open Education Resources) , Open Access and ZTC (Zero Textbook Cost). 

OER and Open Access are materials that are always free to the student but you, as an instructor, may have very different types of information need.

ZTC contains OER but may also contain other resources that may not be free to the student.  These items may include articles from the library databases or ebooks.  These have a cost to the institution but no cost to the student.  

Use the tabs in the box below to learn more about what each of these means.

Open Access and OER Explained

"Open educational resources" describe any copyrightable work (traditionally excluding software, which is described by other terms like "open source") that is licensed in a manner that provides users with free and perpetual permission to engage in the 5R activities:

  1. Retain - the right to make, own, and control copies of the content (e.g., download, duplicate, store, and manage)
  2. Reuse - the right to use the content in a wide range of ways (e.g., in a class, in a study group, on a website, in a video)
  3. Revise - the right to adapt, adjust, modify, or alter the content itself (e.g., translate the content into another language)
  4. Remix - the right to combine the original or revised content with other material to create something new (e.g., incorporate the content into a mashup)
  5. Redistribute - the right to share copies of the original content, your revisions, or your remixes with others (e.g., give a copy of the content to a friend)


"What are OER with ncLibraries?" created by ncLibraries under CC BY

Open access (OA) is a set of principles and a range of practices through which research outputs are distributed online, free of cost or other access barriers. (Wikipedia,

Open access (OA) focuses on those articles that are peer-reviewed literature and research studies Typically we think of OA as research studies and journal articles but OA may also include books, conference papers, individual book chapters and theses.

Open access (OA) access means free to use but not to retain, reuse, revise, remix, redistribute.

The list is ever changing and every growing as more authors are willing to allow access to their books. 

"Open Access Explained" created by Piled Higher and Deeper (PHD) Comics under CC BY


OER was designed to provide students and educators free access to educational materials appropriate for use in curriculum. It has expanded into resources that are free to use both in education and outside of education. OER will always be free.  If it is NOT free, it is NOT OER.

If you are an educator looking for access to free materials for your students which may be more flexible for your classroom then OER may be for you. 

Open Access

While it is tempting to believe that Open Access works are somehow more reliable than OER, it is not the case.

Open Access was designed to enable the sharing of research documents and academic journals online.  It has been extended to also include textbooks. 

If you are an educator looking for free alternatives to the expensive textbooks that your students may be using and you want to use them as they are,  OA may be for you.

Please follow the copyrights attached to any materials you may use, these are Open Access or OER materials and are not public domain (free to use for any reason).

The term “public domain” refers to creative materials that are not protected by intellectual property laws such as copyright, trademark, or patent laws. The public owns these works, not an individual author or artist. Anyone can use a public domain work without obtaining permission, but no one can ever own it.

An important wrinkle to understand about public domain material is that, while each work belongs to the public, collections of public domain works may be protected by copyright. If, for example, someone has collected public domain images in a book or on a website, the collection as a whole may be protectable even though individual images are not. You are free to copy and use individual images but copying and distributing the complete collection may infringe what is known as the “collective works” copyright. Collections of public domain material will be protected if the person who created it has used creativity in the choices and organization of the public domain material. This usually involves some unique selection process, for example, a poetry scholar compiling a book—The Greatest Poems of e.e. cummings.

There are four common ways that works arrive in the public domain:

  • the copyright has expired
  • the copyright owner failed to follow copyright renewal rules
  • the copyright owner deliberately places it in the public domain, known as “dedication,” or
  • copyright law does not protect this type of work.

"Welcome to Public Domain" from the Copyright and Fair Use Libguide Stanford University Libraries CC BY NC 3.0


ZTC means Zero Textbook Cost.  It doesn't mean there is no cost, it means there is no cost to the student.   ZTC's may or  may not be Open Education Resources (OER).

Be sure to check the Merced College Library

Some ZTC materials include:


Infographic of ZTC sources

""ZTC Wheel" by Skyline College ZTC Department CC BY 4.0