Grey literature generally consists of a variety of different publication types produced by governments, organisations, institutions, societies and companies. Grey literature can be in print or electronic format and is not usually published commercially.
Some examples of grey literature publications include: annual reports, datasets, brochures, statistics, white papers, policy reports, doctoral theses, dissertations, blogs, research reports, conference posters and factsheets.
A detailed list of what grey literature consists of can be seen here.
Grey literature is important for many reasons.
1. It allows you to incorporate information such as government statistics and experiments that may not have been published, such as experiments that led to negative or null results. This decreases any bias that may arise if you only chose formally published literature, which is more heavily skewed towards positive results in experiments.
2. It allows you to fully understand the full range of information on offer and come to a more reasoned conclusion as you have broadened your research beyond published material.
3. Grey literature does not have to fit into the guidelines provided by journal publishers and so is usually more detailed than journal articles in terms of the experiment or study methodology and the context surrounding a publication.
While grey literature is incredibly useful it does have its downsides:
1. Grey literature can be quite difficult to find as there is no one complete database due to the vast amount of documents produced by many different governments, organisations and companies.
2. As it is not part of a formal publications process the information does not go through a peer review process so the user must evaluate the quality of the information.
When searching for grey literature, think of your topic. Through research, or your own personal knowledge, make a list of organisations and government departments that you think would produce information relevant to your topic e.g for projects about public health in Ireland, the HSE may have relevant information.
Use Google advanced search to limit the results you get to certain websites, for example, .gov, .org, or .edu. This allows more relevant information to be found; it can also be limited to specific websites, which may provide better search results.
DkIT Multisearch allows you to limit any results to include certain document types such as reports, conference proceedings and trade magazines.