A lot of information produced for educational purposes is considered "grey literature." But what is grey literature?
The Conference on Grey Literature (1999) states grey literature is "That which is produced on all levels of government, academics, business and industry in print and electronic formats, but which is not controlled by commercial publishers." In other words, grey literature is all the "stuff" that is out there not published in a book or journal. Some examples:
Grey literature is a great resource because it often gives insight into a particular topic from a particular point of view. It is also where new ideas often first appear. For example, this white paper published by the California, Nevada, Oregon, and Washington Science Teachers Associations give more information and recommendations for aligning materials with the Next Generation Science Standards.
Most grey literature exists on the open web, you just have to know where to look:
Google Search:
You can do Google search to help find grey literature, but it is recommended to use advanced search features for Google.
Government Websites:
Government websites are the best way to find grey literature as they produce more than anyone else!
Other sources:
Here are a few more useful resources for grey literature.