How to use Overton to decolonise your research and teaching

How incorporating grey literature can enhance your research methodologies

By Ellie Downes, Product Support Specialist at Overton

This guide shows you how and why to use Overton to find public policy and grey literature in your research and teaching.

The Overton Index is the world’s largest policy database. We define a ‘policy document’, as any document made by or for policymakers. This of course includes publications from governments and official bodies, but also materials from IGOs, think tanks and NGOs – groups whose input is generally aimed at influencing policy. This expansive definition makes Overton a powerful discovery tool. By bringing together all of these different types of publication in one searchable place, Overton makes finding grey literature easy. You can use it to unearth a broad range of documents from all over the world, gaining a much deeper and broader understanding of a topic than if you were to use commercially published materials alone. 

In this guide we demonstrate how incorporating policy grey literature can improve your research methods and teaching materials, by removing bias and helping to unearth different views and voices. We also show you the key features of Overton for effective analysis of grey literature.

Whether you’re an experienced academic or an early career researcher we hope it will equip you with new insights and tools with which to approach your work. 

What is grey literature?

‘Grey literature’ refers to the range of information and materials produced that is not commercially published. This includes policy documents, white papers, reports, blogs or government guidelines. It can come from a range of sources, including government, business or academia.

It has historically been difficult to search for systematically, compared with the ease of using an academic database, as it’s produced by a huge number of organisations who all make their publications available in different ways.

On top of this, search engines struggle to index this type of publication, so locating documents using keywords is tricky and time consuming. This means that it’s an under-used resource in academic scholarship.

Overton's coverage

Our goal at Overton is to make this resource more visible and accessible. We combine rich and extensive data with a user-friendly interface – we’re like Google for policy documents.

We collect government guidelines, working papers, reports, think tank publications and more, from 1000s of sources in 188 countries. You can see a complete list on the Sources page within your Overton account.

We are always expanding our coverage, and actively encourage users to suggest new sources from which we can pull documents (users can request adding a specific source by emailing support)!

Why you should incorporate grey literature in your research

Using grey literature as a resource in research can be a powerful tool. For a fully comprehensive systematic review, it’s recommended that you include grey literature. Several manuals including the Cochrane Handbook and PRISMA for systematic review protocol promote the use of grey literature searching.

By diversifying the range of sources that you analyse, you help reduce publication bias and bring in alternative perspectives and underrepresented voices. Importantly, it can also provide access to the most current information on a topic as it is not subject to lengthy publishing processes. 

These considerations are important for any researcher who wants to do quality research and deepen their understanding of an issue, but especially those trying to decolonise their research methodologies.

What is decolonisation?

Decolonisation in universities relates to the “recognition that knowledge and practices in Higher Education have often been formed and shaped by aspects of Western colonialism and racism, and this makes Higher Education an unwelcoming social and intellectual space”

Decolonisation is an active practice and involves challenging your mindset, assumptions and behaviours. It has a broad application across the university – from admissions to promotions to pastoral care – that aims to make higher education more inclusive. 

An important aspect of it focuses on universities as seats of knowledge production. Faculty who want to support decolonisation must consider how they produce and share work that is as unbiased as possible. 

This is a complex and ongoing task, but the starting point is to broaden the type of sources and viewpoints that are used in research and teaching. This helps to expand the accepted wisdom on a topic and challenge the dominant position – a position which has likely been established by privileging certain voices over others. 

Using grey literature enables you to expand the range of views you include in your research. This is especially important when trying to reflect perspectives of communities who have limited representation in global discourse – groups who often excluded from scholarly circles or come from countries who publish less academic work. 

Three ways grey literature improves equity in research

1. It helps address academic publishing bias

Policy documents (especially those which draw on research) are an important way of democratising knowledge. Many policy documents produced by NGOs, IGOs and governments are publicly available so people can read them without having to pay journal fees or other costs associated with academic publishing, which are themselves a barrier to the dissemination of much important research. This limits valuable perspectives and expertise from diffusing to other experts and decision makers, and stops it from making the impact that it should.

The biases in the academic publishing landscape also shape the research agenda and perpetuate focus on issues affecting the Global North while disregarding those affecting the Global South. By broadening the scope of the literature you include in your research with grey literature produced by the Global South, you can contribute to changing that imbalance.

2. It allows you to acknowledge expertise which is often ignored​

Using policy documents is a way of acknowledging the knowledge and contribution of those experts or participants in research who may otherwise be overlooked. This may be local stakeholders, experts who are outside of academia, independent researchers or research participants. 

By doing our best to identify ‘mentions’ of contributors, Overton helps demonstrate the impact of those who do not necessarily have published academic work, but have contributed to policy outcomes regardless. 

Using these sources can also help decolonise research methods by addressing the issue of citation bias (see our interview with Ohio State’s Sheila Craft Morgan for more information), which states that women, people of colour and other minoritised groups are systematically under cited in academic work. 

Where policy documents may not be free from bias, the wider range of evidence presented in them may help recognise or bring these voices to the forefront.

3. It breaks down hierarchies

Depending on the type of policy document and topic you are exploring, using grey literature to inform your research can bring in an element of co-creation into your work. Policy documents can be the result of extensive consultations and/or collaborations with the public, and can contribute to this co-creation of knowledge. 

This can be a key aspect of decolonisation as it attempts to break down the more hierarchical aspects of traditional research, by sharing perspectives and expertise. 

Using Overton to decolonise research

We explore how the features of Overton – and a decolonial mindset – facilitate better and more useful research.

Being able to focus on regions which are traditionally underrepresented in the academic literature can broaden your perspective and improve your understanding of research topics. 

You can actively choose to focus on knowledge produced and created by the people who experience it. Rather than using research produced on a particular country or group by external organisations or researchers, you can use research by the country or group themselves.

Overton helps you not only unearth a diverse range of sources, but also analyse and organise the data in helpful ways, with numerous filters to help you structure or limit your query. 

For example, we provide regional grouping filters which enable you to focus on a particular area or group of countries, like BRICS, EU27, ASEAN or the Gulf States. You can use this to pull grey literature from a wider but similar pool – for example with similar socioeconomic or religious backgrounds.

This is helpful when trying to incorporate perspectives from regions that publish less, as it can be difficult to generate enough data to do a reliable analysis. But with this larger sample, it’s possible to evaluate and compare the outputs more effectively.

By way of example, island nations are already experiencing and having to mitigate and adapt to climate change, therefore their policy documents will be reflective of the research and actions they have undertaken. 

This is an important perspective to forefront in any research into climate change and its effects, as they are happening and responding in real time.

Using source, country and regional filters, we can focus our attention on documents produced by specific countries, islands and territories.

Another example can be found in health. Overton includes policy documents and clinical guidance from NHS Trusts and Clinical Commissioning Groups, but also comparable healthcare agencies and departments across the world. 

This can give you a much broader perspective on different types of healthcare systems, and analyse the public health strategies in similar regions. For example, you may want to analyse how several different equatorial countries manage the effects of tropical diseases (while excluding parts of the world in which that would be irrelevant), or compare how different countries in the Global North address obesity.

Quickfire tips on grey literature search with Overton

Here’s how to search for policy documents in Overton – see the three levels you can incorporate to build depth and complexity.


You can search Overton just as you would search an academic database using key terms, boolean searching and filtering techniques. 

You can select topics or sources and uncover all the relevant policy documents in this category.


If you want to expand the complexity of your search, you can export a search string that you’ve developed in an academic database. You can then use the list of DOIs attached to those articles in Overton by pasting them into the box on the ‘Search Scholarly Articles’ tab. 

If you click ‘Explore’ to see the policy citing these papers, you will get a list of policy documents which cite the scholarly articles from your original search. This adds another layer of depth to your literature search while remaining relevant to your search topic.


Once you’ve created a search string you are happy with in the ‘Policy Documents’ tab, you can save the search, and re-run it periodically to incorporate any new documents. We recommend renaming the searches you save for clarity.

If you want to view only the documents published since your last search, you can click on the search and then use the ‘added after’ date filter.

It is important to note that if you use a set of articles to search the ‘Scholarly Articles’ tab, you will only ever see the policy documents which cite that fixed set of articles. If you wanted to add further scholarly articles to your search, you would need to rerun the search and add the DOIs of the new articles to the initial set.

Transparent reporting of literature reviews and systematic reviews is important for the robustness and replicability of scientific research. Your ability to save searches, and re-run them in Overton can enable you to follow accepted practice for reviews, but you can also include Overton in reporting checklists or flowcharts to demonstrate your methodology such as the PRISMA flow diagram.

Overton user and librarian John Barbrook explains how he uses the platform to decolonise research on our blog. Read it here.


If you’d like to read more about decolonising research methods or literature searching you might find these guides useful:

About Overton

The Overton Index is the world’s largest searchable public policy and grey literature database. We collect millions of documents from policy sources all over the world (including governments, IGOs, think tanks and NGOs) and pull out the evidence that they used in the publication – we identify references to the research, people, organisations and other policy documents that are cited or mentioned.

You can track how evidence is used across the policy landscape, giving you unparalleled insights into how ideas flow from research to policy as well as from policy to policy.

The platform can be used as a research tool, for finding policy and grey literature, and as a tracking tool to find and evidence mentions of individual or institutional ‘impact’ in policy. Importantly, this data allows you to analyse how influence works in the policy sphere, to identify trends and extract learnings about the use of evidence. Overton’s data brings transparency to policymaking.

Access the Overton data yourself

Fill out the form below to get a free trial of the platform, and explore grey literature from all over the world.

by Ellie Downes

at Overton

Ellie is a Product Support Specialist in our Engagement and Training Team. Before Overton she worked as a university research librarian and is experienced at providing support and training to researchers.