OER are educational materials that are specifically designed by their creator/s to be openly available, and are often licensed to be re-used, re-mixed, and re-distributed. Open is not just about low cost (though that is an important benefit of using OER) but about the ability to take what others have created, customize it for your specific educational needs, and then share your creation with others.
OER come in a variety of forms:
The open resource movement has been around for a while, starting with static learning objects (about 2000), and transitioning to OER that allowed for revision and reuse. It is the ever increasing cost of textbooks and materials for students that is now pushing the OER movement forward. Textbooks and learning materials cost students approximately $1,200 per year. According to the Chronicle of Higher Education, 7 in 10 students didn't purchase a textbook because it was too expensive. Through OER the cost of student materials can be drastically reduced. OER also give instructors the ability to customize the materials, creating the "perfect" textbook instead of being bound to traditional print resources.
The terms "open content" and "open educational resources" describe any copyrightable work (traditionally excluding software, which is described by other terms like "open source") that is either (1) in the public domain or (2) licensed in a manner that provides everyone with free and perpetual permission to engage in the 5R activities:
Defining the "Open" in Open Content and Open Educational Resources was written by David Wiley and published freely under a Creative Commons Attribution 4.0 license at http://opencontent.org/definition/.