"OER are teaching, learning, and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use and re-purposing by others. Open educational resources include full courses, course materials, modules, textbooks, streaming videos, tests, software, and any other tools, materials, or techniques used to support access to knowledge." 
The Open Education movement is built around the 5Rs of Open 
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Surveys show that 65% of students do not purchase course required textbooks because of the expense. They also show that 94% of those students who forgo purchasing a textbook are concerned that doing so would hurt their grade in the course. 
Too frequently, students feel forced to choose between not purchasing textbooks (presumably resulting in less learning) or taking fewer classes (resulting in slower time to graduation) in order to manage or reduce college costs. Data has shown that students using OER enroll in a significantly higher number of credits that students who do not.