Open educational resources (OER) are materials used for educational purposes that are free for anyone to access. They are also licensed to enable uses such as sharing and revising. OER can be textbooks, syllabi, test banks, homework assignments, articles, podcasts, videos, slides, and more.
The short video below introduces the general concepts of open educational resources.
The video below is a brief report on research on the effectiveness and perceptions of OER as compared to commercial textbooks.