Good question. Most platforms like Pressbooks that people use to make OERs are open to anyone who wants to write. Getting a textbook onto a platform like the Open Textbook Library, on the other hand, probably does require an author to jump through some hoops establishing their bona fides. Even so, it's a lot less restrictive than getting the attention of a publisher, and more based on the quality of the writing. The reviews the Library sponsors are very in-depth and ask a lot of detailed questions.
Does the OER encourage contributions from independent scholars or do they prefer that writers be formally affiliated with a university?
Good question. Most platforms like Pressbooks that people use to make OERs are open to anyone who wants to write. Getting a textbook onto a platform like the Open Textbook Library, on the other hand, probably does require an author to jump through some hoops establishing their bona fides. Even so, it's a lot less restrictive than getting the attention of a publisher, and more based on the quality of the writing. The reviews the Library sponsors are very in-depth and ask a lot of detailed questions.