Finding grey literature

Grey literature is produced by governments, companies, charities and other organisations, rather than by commercial publishers. It's an extremely useful way of gaining a deeper insight into a subject.

It includes:-

While not strictly speaking grey literature, it may also be useful to find secondary data sets relevant to your research or read articles in the mainstream news.  You may also like to look at your 'subject' page (see link on the top bar) for further resources, such as information and statistics about companies, markets and industries and specific law databases.  If you have any questions, please contact The Library and we can help you further.


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Why look at grey literature?

Grey literature should be used in addition to academic research, rather than instead of it. It can offer many things -

New findings and research can appear in grey literature (e.g. in working papers) before they are formally published in peer-reviewed publications.

Grey literature allows you to read research findings from beyond academia and traditional models of publishing (e.g. from industry).

It can be more industry or sector focused, rather than academic.

It includes reports from professional organisations, which may offer a more practical insight into particular issues or examine a topic in greater depth.

With regards to research into health care, searching for grey literature helps to avoid "publication bias". Publication bias is the (unfortunate) fact that research projects showing the positive effects of a drug or treatment are more likely to be published in journals, compared to those showing no or negative effects. As all trials now have to be registered, searching grey literature will uncover this bias. See the clinical trials section below.


Also, if you're an academic or researcher and you want to investigate the potential impact of your own research, then exploring grey literature can be a useful way of seeing where your work has made a difference in the real world.


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What should I be careful of?

While there are many positives of grey literature, you do need to be vigilant. You must - 

Always consider its source. Is it verifiable and reliable?  Do not use anything unless you are sure you can verify where it came from and who wrote it. One way of checking this is to look at the website's domain. e.g. official UK government documents should always be on a website ending in

Grey literature typically isn’t peer reviewed.  You will need to critically review it, considering any errors or inaccuracies that it may contain.

While anything may contain some bias, grey literature may be more susceptible to containing bias. For example, a report produced by a company may be written from a certain perspective. If you think that it may contain bias, then you should explain this in your work.

If you are in any doubt at all about the validity of something that you've found, then please contact the Library.


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How do I find grey literature?

Unfortunately there’s no simple answer!  You will need to do some detective work and it depends very much on what you’re looking for.  We’ve given some suggestions below, but if you need further help then please contact the library.


Company and organisation websites

OK - let's start with the obvious!  If you're interested in a particular company or organisation, then it's usually best to start with their website. If their website is unfathomably complex, then try using an Advanced Google Search of their website (see below).


Google and Google Scholar

As you’re probably aware, just plugging keywords into Google will probably result in an avalanche of information, most of which is either irrelevant or you've no idea who actually wrote it!  So here's a few tips that will turn Google into a much more powerful search tool. 


Tip 1: Use an Advanced Google Search

Using an Advanced Google Search lets you -

Advanced google search
If you are an academic looking for evidence of your research's impact then you can search for your name in the 'this exact word or phrase' box (above).


Tip 2: Use Google Scholar, rather than Google

Google Scholar is similar to Google, but it will only show you research focused things. This includes a lot of journal articles and books, but it also includes government policies, technical reports, and much more.


Tip 3: Used an Advanced Search within Google Scholar

To turbo-charge Google Scholar, use it with the advanced search terms. This makes your search even more targeted and you can find all sorts of interesting things ...

To search a specific website, use the term “site:”

For example, to search for reports on knife crime produced by the police, use the search term "knife crime"

Google scholar

Or for example, to search for NHS reports on stopping smoking, use the search term smoking

Google scholar

Or for example, to search a particular company, use a search similar to

Google scholar

Government reports

Government reports are posted on government and local authority websites. The web address for these end in “.gov.something”   For example -

You can either visit and search the websites directly. Or if the websites are difficult to use, try using an Advanced Google Search (described above) and restrict the domain to the website. 

If you are specifically interested in the UK, then these shortcuts may be useful -

Publications - example social care.
Consultations (open and closed) - example Network Rail.
Announcements - example Defence and Armed Forces.

From time-to-time, the government may tidy up their website and remove reports. If this happens, then please search the UK Government Web Archive.


PhD theses

Most countries have a central database where all PhD completed theses are shared. Some main ones are listed on our finding past PhD theses page.




Altmetrics let you find when mainstream news articles, social media, patents, government policy documents etc have referenced a particular academic journal article. This is a useful way of seeing an article's influence on the 'real world'. Instructions for looking up Altmetrics.


Open grey

"System for Information on Grey Literature in Europe, is your open access to 700.000 bibliographical references of grey literature (paper) produced in Europe and allows you to export records and locate the documents." Visit Open Grey


Standards and patents

A standard is a set of criteria or technical specification, which manufacturers and service providers are either required or recommended to conform to. Laws or regulations can make it compulsory to comply with a specific standard. British Standards Online and ETSI (European Telecommunications Standards Institute).

A patent protects a new invention. It gives the inventor the right to stop others using, making or setting it without permission. It provides a detailed description of the invention.  Patents can be an important source of information about very recent developments that have not yet been described in journal articles or conference papers.  They can also provide you with an overview of recent technical developments in an area. Please see esp@cenet worldwide network of patent databases and Google Patent Search.


Medical and health care

Clinical trials registers

Clinical trials approved by ethics committees should now all be registered with an international registry (database).  This includes results that were not actually published in formal publications. There are several registers to look at -

WHO Primary registries
US National Library of Medicine
Research Registry

Other useful sources

NHS evidence

Social Care Online: The UK’s largest database of information and research on all aspects of social care and social work.

Popline: Comprehensive collection of population, family planning and related reproductive health and development literature.

TRIP medical database: Search engine for clinical guidelines, synopses of evidence, systematic reviews, journal articles, clinical trials, medical images and videos, patient information, etc.

Reports from large organisations

King’s fund publications

UNESCO documents and publications

World Health Organisation (WHO)


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