Open educational resources (OER) provide more accessible and affordable education globally by allowing users to access information without incurring high costs. OER gives students more options for how to learn through downloadable assignments or videos. It also allows students to review materials after courses and share knowledge with others. However, determining quality can be difficult and some instructors may feel ownership of their work is threatened by OER since it is a relatively new concept. Maintaining high quality OER sites over time can also be an expensive challenge.