The Meriam Library at Cal State Chico developed the CRAPP test for evaluating websites:
The short version -- Look at:
Download the full one page document for more information.
While this article has been published on a multiple sclerosis website, it was written by a librarian and succinctly describes evaluating websites for content.
Achieve is a non-profit, non-partisan educational organization working to reform education. They have developed a robust evaluation tool to use to thoroughly examine the efficacy of OERs.
These rubric is used on OER Commons to evaluate materials. They also make the code available for others to use.
They provide a rubric to evaluate the facets of OER: