• Grey literature is often the best source for up-to-date research on certain topics. This is because it doesn't have to undergo the often lengthy publication process before it can be reviewed.
• In the same breath, grey literature databases can have a scope that includes recently emerging research areas.
• Scientific publishing, for instance, has a strong bias toward publishing research that shows a significant positive correlation. Many studies show no effect and can go unpublished, but negative results are just as important to note. Accessing grey literature fills this knowledge gap, and generates a more balanced picture of the available evidence.
• The reports produced in grey literature are often more detailed in nature and can contain raw data sets not available anywhere else - the caveat is that they come in tons of different formats and document types, making the data slightly more difficult to find.
• Grey literature can help researchers to reduce publication bias.
• Most grey literature is free (one exception is materials produced by market research firms, which often charge for access), making it much more accessible to everyone.

What are some of the drawbacks of grey literature?

• The information in grey literature hasn't gone through the usual publishing channels, so it isn't rigorously and formally peer-reviewed. This means you'll need to carry out your own checks to assess its reliability.
• When grey literature isn't published, it's free from publication bias. However, it may carry its own set of biases. The organization that distributed the grey literature can have its own political, social, or financial motivations for promoting unreliable research. Make sure to cross-check information from grey literature against studies found elsewhere.
• Grey literature is produced from a great variety of sources, so it's usually not indexed or organized in any way. That can make it very difficult to locate what you're looking for.
• Librarians often have a difficult time acquiring grey literature and making it accessible.

What are some examples of grey literature?

Publication types of grey literature are almost endless, and include:

• Government reports
• Technical reports
• Unpublished clinical trials
• Conference abstracts
• Graduate dissertations and theses
• Newsletters
• White papers
• Patents
• Working papers
• Blogs
• Dissertations
• And more

Websites, manuals, statistics, and datasets are technically also types of grey literature that you may come across during the research process.

How do you identify grey literature?

Grey literature can be found in so many contexts it can be tough to list them all. Essentially, if you didn't find it in a renowned journal or published book, there's a good chance it's grey literature. Luckily, if you know how to find academic sources, you should be able to identify grey literature in the wild. Here are some other indicators that you may be looking at a piece of grey literature:

• It was difficult for you to find
• It hasn't been widely distributed
• It contains more information on the subject than you've seen elsewhere, as there weren't publication length stipulations
• It was produced and disseminated quickly
• It hasn't been archived