OER Commons uses the rubrics created by Achieve, Inc. to evaluate the quality, potential effectiveness, and degree of alignment with Common Core Standards of the OER materials in its library. It applies the rubrics directly to these materials, rating them on a scale of 1-3, with 3 representing a superior ranking.
In general, you should look at the following:
Author's Qualifications and Affiliations
Date of Publication
Documentation of Sources
Suitability of the Work for your Purposes
Review and Curation Process
Restrictions/Licenses of the Work