Despite some limitations, Overton, a database of policy documents and gray literature, is a valuable tool for users who want to understand the intersections of policy with scholarly research.
In a world where policy decisions shape societies, understanding how scholarly work intersects with policy is a crucial part of measuring the influence of research beyond the walls of academia.
Overton Index is a large database of policy documents and gray literature, sources that are usually harder to find than academic research, making it a valuable tool for faculty, researchers, and students looking to broaden their literature searches. What makes Overton especially useful is that it also tracks where and how scholarly works—like journal articles, books, and book chapters with DOIs—are cited in policy documents from around the world, helping users uncover their real-world reach.
Overton indexes over 20 million policy documents. It serves a wide audience—faculty, students, librarians, and administrators—and is useful both as a source for gray literature and policy documents and as a tool for analyzing how academic research is cited in policy. A newer feature, “Engage,” helps users find opportunities worldwide to engage in the policy-making process, including consultations, funding, fellowships, learning agendas, and more. A free version of Engage , which gives users basic access to browse and discover some calls for evidence and engagement opportunities, is integrated into the Overton database. A paid version provides more extensive features, such as advanced search/filtering, search alerts, semantic searching, tagging opportunities, tracking or exporting opportunities, and access to training materials (Collard, 2025).
Overton defines policy documents broadly as those written “primarily for or by policymakers” and published by policy-focused sources (Overton, 2024d). These documents aren’t always tied to formal policy changes, but citations in them can reflect how academic research influences reports, briefs, and speeches encountered by decision-makers.
The database gathers documents from local and national governments, intergovernmental organizations (IGOs), non-governmental organization (NGOs), and think tanks. About 60 percent of its content comes from the US, UK, Canada, France, Japan, and Germany. Another significant share (10 percent) comes from global organizations such as the World Health Organization (WHO), United Nations Educational, Scientific and Cultural Organization (UNESCO), the World Bank, and the United Nations. While most coverage skews toward the Global North, Overton includes materials from around the world and does better than many academic databases at indexing documents in local languages. Some countries in the Global South, including Peru and Uruguay, are relatively well-represented (Overton, 2021; Szomszor & Adie, 2022).
Roughly 88 percent of documents in Overton lack DOIs, which is expected given the type of content—reports, proceedings, commentaries, and other gray literature. Only about 14 percent of documents include references to other policy or scholarly work (Szomszor & Adie, 2022). Even so, Overton offers insights into how research enters public discussions and policy processes.
There’s growing interest in whether policy citations reflect real-world “societal impact.” A study by Szomszor and Adie (2022) found that in the UK, fields where researchers reported impact also tended to have more policy citations in Overton—a promising sign. But policy citation rates are low overall: only 3.9 percent of Web of Science articles are cited in policy documents (Fang et al., 2024), and some relevant research may still be uncited. As Noyons (2019) suggests, other approaches—like topic analysis of policy documents and legislation—can help experts in research analytics or research evaluation assess policy relevance and its applicability to research and researchers.
Users may be surprised to discover that in Overton, the social sciences and humanities appear most often in policy citations, despite being less cited in traditional academic metrics, followed by life and earth sciences and biomedical and health sciences (Szomszor & Adie, 2022; Fang et al., 2024). This contrasts with tools like InCites, where the top-cited fields, such as engineering and biomedical sciences, are often in science, technology, engineering, and mathematics (STEM).
Overton also integrates generative AI to summarize and identify the themes of policy documents. These AI tools are run locally, with occasional cloud use under strict privacy conditions (Overton, 2024b). Users can view summaries and document descriptions directly from the results page (Figure 1).
A recent Financial Times report explored new methods to measure and promote research that is relevant to global issues and applicable in practice (Jack & Dala, 2024). The authors analyzed FT’s business school rankings to highlight the broader impact of these institutions in policy, teaching, industry, and academia, with Overton as one of its data sources, demonstrating that such resources are becoming more important in academia.
Overton’s advanced search tools include Boolean operators, quotation marks, the ~ operator with proximity numbers, and parentheses to refine queries (Figure 2).
By default, Overton connects unquoted search terms with a Boolean AND—for example, climate change mitigation becomes climate AND change AND mitigation. The system will suggest searching the exact phrase to narrow results (Figure 3).
Search results show highlighted text within the document and link directly to the relevant page for easy access (Figure 4).
After searching, users can apply a wide range of filters, including cited institutions, policy source type (e.g., government, IGO, think tank), document type, country of origin, year, Sustainable Development Goals, language, subject area, people cited, and more.
Users can also search by the DOI, Open Researcher and Contributor ID (ORCID), PubMed Identifier (PMID), or ISBN of specific scholarly works to find the policy documents that cite them—up to 3,000 identifiers at once. Searching by author name is also possible using the “Search People” option, but results may be less complete due to name ambiguity. Using unique identifiers is generally more accurate.
When users search for mentions of scholarly works, the results report how often and where they are cited in policy, with short snippets of the policy text shown for context (Figure 5).
By selecting “See the policy citing these papers” in the Explore tab, users can view the policy documents citing a set of scholarly works (e.g., from a research group), complete with snippets of text showing the citations and links to in-text mentions (Figure 6).
Explore options also include:
Export options vary by page type. For policy document results, users can export:
For citations of scholarly articles, exports include:
Batch exporting isn’t currently supported, so users are limited to these predefined export sets. But to perform larger, more comprehensive data downloads for more in-depth analyses, users with institutional subscription access can typically get access to the application programming interface (API) (Overton, 2025b).
An analytics dashboard breaks down results by country, document type, year, source sector, funders, cited institutions, Sustainable Development Goal categories, and more. Each category can be exported as CSV for use in custom tables or visualizations.
Users should consult “Using policy related metrics responsibly in research assessment” (Overton, 2024c) regarding the limitations of the analytics dashboard feature.
Overton is WCAG 2.1 compliant at Level A and is working toward Level AA, with improvements to color contrast and font sizing underway. The interface is designed for clarity and accessibility, supporting screen readers, zoom up to 200 percent, keyboard navigation, and speech recognition (Overton, 2024a). A detailed VPAT is available (Overton, 2025a).
Overton calculates an initial price for an institution using a formula based on the institution’s annual number of publications, as sourced from OpenAlex. Renewal prices increase by percentage each year, which makes future pricing predictable. Typically, Overton applies a three percent annual increase for universities; they do not fix prices for multiyear agreements.
To put some numbers on it, the 2025 institution-wide prices for Overton Index generally range from $10–30k (with larger R1 institutions coming in higher and less research-intensive organizations coming in lower). For users who elect to subscribe to the paid version of Overton Engage, the annual fee is in the same price range. For institutions that purchase both products, Overton applies a 50 percent discount to the price of one.
Additionally, Overton offers a five-seat team license that allows smaller groups within a university to use Overton independently, or as a steppingstone to advocate for campus-wide access later on.
Although Overton’s index is not currently COUNTER-compliant, the platform can generate usage reports detailing session and page views by month or by user. Overton is most comparable to other research analytics tools, such as SciVal and InCites, where COUNTER reports are typically less pertinent. Most users tend to export reports and datasets for their own offline impact analysis; full-text policy documents are accessible via PDF URLs included in exported files. As a result, standard COUNTER reports may not adequately capture the complete range of user engagement with Overton.
Because Overton provides direct links to the full text of policy documents on external sites or, when possible, to publicly archived versions, interlibrary loan options are not relevant. Similarly, text and data mining are generally unnecessary, as the platform only links to documents that are freely and externally available. That said, Overton is working to indicate when standard licenses—such as government public domain licenses—apply, so users do not need to independently verify usage rights on outside sites.
In the event that Overton ceases operations, the platform itself would become unavailable. But a comprehensive metadata snapshot of all policy documents within Overton would be shared with a select group of academic partners, who would be authorized to distribute the data as needed.
Overton offers several authentication options. Site license subscriptions typically rely on IP address recognition and proxy services, such as EZproxy, for seamless on-campus and remote access. The platform also supports user registration with institutional email addresses, provided the organization’s domain has been verified. For institutions using federated identity systems, Overton supports OpenAthens and other SAML-based authentication protocols, including Shibboleth. Organizations may configure SAML Single Sign-On (SSO) to allow users to log in using institutional credentials. In some cases, integration with EBSCO or other platforms may extend support to both federated and 1:1 SAML SSO configurations, depending on local infrastructure. While Overton is not currently part of a read-and-publish or transformative agreement, authentication methods are designed to accommodate a range of institutional access and identity management needs.
Two major products often compared to Overton are Altmetric Explorer (AE) and Policy Commons, though each serves a distinct purpose.
Altmetric Explorer and Dimensions
AE tracks online attention to research outputs with DOIs, including from social media, news articles, blogs, policy documents, Wikipedia, and YouTube. While Overton focuses solely on policy citations, AE feeds its policy citation data into Dimensions, which also connects research to grants, patents, trials, and datasets.
Other key differences between Overton and AE/Dimensions:
Policy Commons
Policy Commons is a broad platform for policy and gray literature but does not specifically track citations within documents; the vendor has indicated that this feature is under development. Policy Commons does have a tool that enables users to search for any mention of specific organizations, such as governments, news media organizations, higher education institutions, banks, and corporations, within the policy documents (Coherent Digital, 2024), helping organizations to demonstrate their impact beyond citations.
By contrast, Overton tracks citations of research outputs by authors affiliated with institutions of higher education specifically. Overton users can search the database by institution as well, but the search is limited to research published by the institution, not for broader mentions of the institution within policy documents. In other words, the search is limited to the institution’s own outputs, rather than references to the institution itself. As a workaround, Overton users can search for an institution or organization as a keyword, which may return similar results. Like Policy Commons, it displays snippets of where the keyword is mentioned in the document.
As of July 2025, Policy Commons includes ~20 million publications from 42,000+ organizations, while Overton includes slightly more at 20.5 million documents from 46,000+ sources. The two platforms differ in focus:
Policy Commons allows users to subscribe to specific content modules (e.g., African history or global studies), while Overton emphasizes tracking research-policy interactions through citation analysis.
Overton acts as both a searchable policy document database and an altmetric tool for tracking scholarly citation in policy literature, complementing traditional bibliometrics by highlighting societal impact (Pinheiro, Vignola-Gagné, & Campbell, 2021). Its intuitive interface features contextual citation views and in-text highlighting. Functions like report generation and data export have a learning curve.
A key limitation is Overton’s exclusive reliance on DOIs to track policy citations to research outputs, which excludes gray literature and research outputs lacking persistent identifiers. This reduces visibility for books, reports, and disciplines less tied to digital publishing. However, it’s worth noting that comparable analytic tools, such as Altmetric Explorer and SciVal, also rely heavily on DOIs. Overton only links to, rather than preserves, policy documents, which risks link rot—although links to archived documents are included when available. By contrast, Policy Commons provides more sustainable access by archiving documents and assigning them persistent identifiers.
Engage offers researchers fewer than 4,000 indexed policy engagement opportunities. AI-generated document summaries are promising but not exportable, limiting users’ ability to integrate them into reports and further analysis.
The snippets of text that are displayed with mentions—whether of a specific citation, a researcher, or search terms—can be exported. But the usefulness of the export feature is limited by the treatment of snippets of citations: instead of exporting the in-text citations (and surrounding snippet of text), Overton exports the full reference. This makes it difficult to perform more meaningful analyses, since the in-text citations reveal the contextual information about how sources are being used.
Reports can be publicly shared, including to non-subscribers.
Overton’s contract allows unlimited user seats and institutional API access, with pricing scaled to institution size, but, due to its reliance on externally available documents, lacks preservation guarantees. Despite these limitations, Overton is a valuable tool for analyzing research-policy intersections, provided institutions are aware of its functional and coverage constraints.
Universities are increasingly asked to provide evidence about their value to the public, especially when they are supported with tax dollars. Regardless of whether policy citations eventually result in concrete policy changes, their presence in policy discussions is a meaningful indicator of how broader audiences are engaging with research. Policy citations show that research outputs are not only reaching policymakers but are also being consumed and considered within public and governmental spheres. This demonstrates a tangible connection between scholarly work and public discourse, highlighting the broader societal influence of research beyond academic circles.
I recommend Overton to users who want to understand this phenomenon.
University administrators, research managers, and research evaluators can leverage Overton to gain a deeper understanding of how society is engaging with their institution’s research and how policymakers are adopting it, providing a valuable layer of insight beyond traditional academic metrics. For individual researchers, Overton presents an opportunity to track how their work is cited within policy documents. Such insights can encourage institutions or individuals to develop strategies to focus on policy-relevant topics.
Overall, access to policy citation data can support a more informed approach to research and the assessment of its influence, fostering awareness of the broader societal context in which scholarly work is discovered and can ultimately have influence.
Coherent Digital. (2024, April 8). New tool on Policy Commons enables impact analysis for millions of items of gray literature. Library Technology Guides. https://librarytechnology.org/pr/29950
Collard, S. (2025, January 22). Overton Engage explained: Paid subscription vs free account. Overton blog. https://www.overton.io/blog/overton-engage-explained-a-paid-vs-free-subscription-whats-the-difference
Fang, Z., Dudek, J., & Nyons, E. (2024). Science cited in policy documents: Evidence from the Overton database. arXiv. https://doi.org/10.48550/arXiv.2407.09854
Jack, A., & Dala, A. (2024, November 8). Business school and the pursuit of rigour, resonance and relevance. Financial Times. https://www.ft.com/content/7e81e1b6-eb08-43de-ab71-ab6c50181cc3
Noyons, E. (2019). Measuring societal impact is as complex as ABC. Journal of Data and Information Science, 4(3). https://doi.org/10.2478/jdis-2019-0012
Overton. (2021). How international are your sources? Overton Knowledge Base. https://help.overton.io/article/how-international-are-your-sources/
Overton. (2024a). Accessibility statement. Overton Knowledge Base. https://help.overton.io/article/accessibility-statement/
Overton. (2024b). How does Overton generate document descriptions? Overton Knowledge Base. https://help.overton.io/article/how-does-overton-generate-document-descriptions/
Overton. (2024c). Using policy related metrics responsibly in research assessment. Overton Knowledge Base. https://help.overton.io/article/using-policy-related-metrics-responsibly-in-research-assessment/
Overton. (2024d). What’s your definition of a policy document? Overton Knowledge Base. https://help.overton.io/article/whats-your-definition-of-a-policy-document/
Overton. (2025a). Open Policy Ltd Accessibility Conformance Report WCAG Edition [VPAT Report]. Overton. https://help.overton.io/wp-content/uploads/2021/11/2025-Overton-VPAT.pdf
Overton. (2025b). Overton’s API. https://www.overton.io/overton-api
Overton. (2025c). Policy engagement opportunities. Overton Knowledge Base. https://help.overton.io/article/policy-engagement-opportunities/
Pinheiro, H., Vignola-Gagné, E., & Campbell, D. (2021). A large-scale validation of the relationship between cross-disciplinary research and its uptake in policy-related documents, using the novel Overton altmetrics database. Quantitative Science Studies, 2(2), 616–642. https://doi.org/10.1162/qss_a_00137
Szomszor, M., & Adie, E. (2022). Overton: A bibliometric database of policy document citations. Quantitative Science Studies, 3(3), 624–650. https://doi.org/10.1162/qss_a_00204
10.1146/katina-091725-1
