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Grey Literature Guide: Grey Literature

Understanding Grey Literature

When starting to explore grey literature, it’s important to understand what it is and why it matters in your research. Grey literature refers to information and research materials that are not published through traditional commercial or academic channels. Examples include: government reports, policy documents, white papers, conference proceedings, etc. These resources can provide valuable insights and unique perspectives that are often not found in traditional academic publications.

In this section, we’ll define grey literature and discuss its significance in academia.

What is Grey literature?

Grey (or 'Gray') literature can be generally defined as everything other than scholarly journal articles and books. It is essentially any information source that has not been formally published, either academically or commercially.

The most widely accepted definition comes from the 2010 International Conference on Grey Literature:

Grey literature stands for manifold document types produced on all levels of government, academics, business and industry in print and electronic formats that are protected by intellectual property rights, of sufficient quality to be collected and preserved by libraries and institutional repositories, but not controlled by commercial publishers; i.e. where publishing is not the primary activity of the producing body.

A wide range of material can be considered grey literature:

 

Different types of grey literature are useful for different research. Clinical trial data is highly relevant to medical researchers, while company reports and market research are particularly valuable for business researchers.

Remember:

Before you start searching, consider the specific types of grey literature that align with your interests and needs. This focus will help you target your search more effectively and frame it with greater precision.

Why use grey literature?

Grey literature is a key source of information and is uniquely useful for many reasons.

  • Up to date: Since grey literature isn't formally published, it can be produced at a faster rate than a scholarly journal article or book. Grey literature is often the most current source of information on a topic because it can react to developments quickly. 
     
  • New and emerging research areas: Because grey literature isn't subject to publication delays, it provides information on new research areas which published literature may not yet have addressed. Grey literature can be the only available source when there is no published literature on a topic, so it helps to fill gaps in academic literature.
     
  • Free and open access: Most grey literature sources are free to access, with no paywalls. 
     
  • Avoids publication bias: Niche literature on less popular research topics, or which differs from the positive findings of other research studies, is less likely to be formally published. Grey literature can include more unique research, including studies with null or negative results​.
     
  • Global perspectives: The majority of published academic literature comes from sources in the global north (e.g. the US, Canada, the UK). In contrast, grey literature is produced by hundreds of thousands of organisations all across the world, representing a more diverse range of voices.
     
  • Insights outside of academia: Grey literature also offers important perspectives from contexts outside of academia. Grey literature publications can illustrate how research impacts policy, industry and everyday life and is often a great source of evidence-based practice. It explores the practical applications of research, considering what steps to take in the light of the academic evidence. 

 

There are also some important limitations to keep in mind when working with grey literature: 

  • Grey literature varies in quality. Unlike with academic journals and books, grey literature is not subject to a formal, scholarly peer-review process​. However, many grey literature sources do come from reputable sources with the authority to gather information, like governments, international organisations and charities. Some grey literature sources will undergo a form of peer-review. For example, theses have been marked and checked by scholars with relevant expertise, and government reports are checked and edited thoroughly. Just keep in mind, not all sources will have been quality-checked, and not to the same degree, so it's important to evaluate the grey literature sources you find. 

  • Grey literature can change or disappear. Because grey literature is not formally published, it's not fixed. The information could be changed or the source could be removed completely. Make sure to keep a record of the grey literature sources you find, and capture the version you saw. 

 

Acknowledgements

This guide was inspired by:

Next Section: Finding Grey Literature

Grey literature encompasses diverse sources and requires a strategic approach to locate relevant materials for your research. The next section, will introduce specific techniques and resources for effectively locating relevant grey literature.