Grey literature is information "produced on all levels of government, academics, business and industry in print and electronic formats ... but not controlled by commercial publishers ..." (Schopfel, 2010).

Reference

Schopfel, J. (2010). Towards a Prague definition of grey literature. https://opengrey.eu/item/display/10068/700015-2/

Grey Literature Tutorial (2:39 mins) by Western University (YouTube)

Grey literature is used for various reasons, offering both advantages and limitations:

Advantages

• Introduces alternate viewpoints: Offers diverse perspectives not found in mainstream publications.
• May be the only source of information: For instance, unpublished studies can provide unique insights.
• Provides first-hand accounts of events: Diaries and personal narratives offer direct perspectives on historical events.
• Minimizes reporting or publication biases: More likely to include negative results, providing a balanced view, especially in clinical trials.
• Provides new information not yet published in traditional sources: Conference papers often contain cutting-edge research.
• Provides more local information: Government reports and local collections offer detailed regional or community-specific information.
• Is a source of raw data: Data sets and statistics crucial for research and analysis.

Limitations

• Often excluded from large databases and other mainstream sources: Making comprehensive collections harder to find.
• Is not peer-reviewed: Raising questions about the reliability and validity of the information.
• Often difficult to locate: Scattered across various sources, making it challenging to find.
• May only be available in obsolete formats: Complicating access due to outdated formats.
• May not be publicly available: Access restrictions can limit availability.