Grey literature is information produced by governments, industry, non-government organisations and community groups. It often comes in the form of briefing papers, government documents & reports, issues papers, discussion papers, white papers, policy papers, fact sheets, market reports & annual reports.
It has not gone through the process of peer review like scholarly literature, but is often rigorously researched, well referenced, and written by experts in the subject area.
Like any resource you are using for your assessment, grey literature needs to be evaluated based on a number of considerations:
Grey literature is rarely found in academic libraries, it is mostly published on websites, and can be easily found during a Google search. Where you search is key to finding what you are looking for so try a Google Advanced search using a government or organisation domain to filter your results like this:

Australian Policy Online is an extensive collection which reinforces quality search results across articles, grey literature, reports, video, digital, infographics and guides available within the Informit database. Sharing the latest in policy knowledge and evidence, this database supports enhanced learning, collaboration and contribution.
Overton is a searchable index of over 12 million full text policy documents and grey literature from 32,000 organisations in 188 countries including policy documents, guidelines, think tank publications and working papers. Each document is parsed to find references, people and key concepts which are then used to link them to relevant news stories, academic research, think tank output and other policy.
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