When I talk about OER, I often am asked about the quality of the material. The assumption from some is that if something is free, it isn't any good. Others sarcastically point out that we pay a lot for content in schools today and the test scores and dropout rates are not necessarily stellar. We can mock the over-simplification of either side, but we do need to pay attention to quality. How do you go about judging the quality of OER or any other digital content that has not gone through a vetting process?
One excellent source is OER Commons. You can browse thousands of resources by subject and grade level, see a short description, contribute content, rate, review and comment on the materials based on six different criteria and for many materials, see the common core state standards that the materials are aligned with.
OER Commons is a project from the Institute for the Study of Knowledge Management in Education (ISKME) and worth checking out. Do you know of other sites that offer some kind of vetting for OER?