Open Educational Resources (OER) are free, publicly available materials for teaching, learning, assessment, and research. The resources include openly licensed text, videos, photos, and other forms of digital media. Unlike regular copyrighted materials, such as many textbooks, OER creators reserve few, if any, of their ownership rights.
OER require no payment, only Creative Commons attribution in certain cases. This makes them an excellent resource for students and professors, who no longer have to pay exorbitant prices to receive high-quality educational materials.
Creative Commons attribution is fairly easy to understand once you've read over the different types. The basic principles should be familiar to anyone who has worked with MLA, APA, Chicago, or any other form of citation.
Most OER are fully available online, making them easily accessible for both distance and classroom learning. There are also print materials available in some cases for those who prefer physical copies.
Here's where you can learn more about OER.