A good OER includes basically the following:
- being findable - it can be in multiple locations
- clearly described
- clearly licensed (normally through Creative Commons)
- from a reputable source
- easy to modify (if permitted in terms of the license)
- free-standing, that is, it does not assume knowledge of other resources
- free if copyright content
- being used by or recommended by peers and colleagues
Sourced from: The Open University. OpenLearn. Creating open educational resources. What makes a good OER?