Grey (or gray) literature is project or research literature published outside of peer-reviewed journals and other traditional channels. Often this means reports from government or non-governmental organisations. It includes working papers, websites, conference presentations, clinical guidelines, and clinical trial data sets.
Grey literature is usually produced by those who are working in the area and so may offer a more pragmatic and immediate point of view. Most grey literature is not peer reviewed, so you need to use your judgement and assess it to decide whether it is a high quality resource.
Google is a great place to start, but there are heaps of other great resources out there. We’ve put together some lists to help you find what you’re looking for, as well as some tools to help you evaluate what you find. For some general tips on how to search, check out our Search Tips guide.