grey literature


Grey literature (or gray literature) is materials and research produced by organizations outside of the traditional
commercial Commercial may refer to: * a dose of advertising conveyed through media (such as - for example - radio or television) ** Radio advertisement ** Television advertisement * (adjective for:) commerce, a system of voluntary exchange of products and se ...
academic publishing Academic publishing is the subfield of publishing Publishing is the activity of making information, literature, music, software and other content available to the public for sale or for free. Traditionally, the term refers to the creation an ...
and distribution channels. Common grey literature publication types include reports (
annual Annual may refer to: *Annual publication, periodical publications appearing regularly once per year **Yearbook **Literary annual *Annual plant *Annual report *Annual giving *Annual, Morocco, a settlement in northeastern Morocco *Annuals (band), a ...
, research,
technical Technical may refer to: * Technical (vehicle), an improvised fighting vehicle * Technical analysis, a discipline for forecasting the future direction of prices through the study of past market data * Technical drawing, showing how something is con ...
, project, etc.),
working paper A working paper or work paper may be: *A preliminary scientific or technical paper. Often, authors will release working papers to share ideas about a topic or to elicit feedback before submitting to a peer review Peer review is the evaluati ...
s, government documents,
white paper A white paper is a report or guide that informs readers concisely about a complex issue and presents the issuing body's philosophy Philosophy (from , ) is the study of general and fundamental questions, such as those about reason, Metap ...

white paper
s and
evaluation Evaluation is a system A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundarie ...

s. Organizations that produce grey literature include government departments and agencies, civil society or
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, academic centres and departments, and private companies and consultants. Grey literature may be made available to the public, or distributed privately within organizations or groups, and may lack a systematic means of distribution and collection. The standard of quality, review and production of grey literature can vary considerably. Grey literature may be difficult to discover, access, and evaluate, but this can be addressed through the formulation of sound search strategies.


While a hazy definition of "grey literature" had existed previously, the term is generally understood to have been coined by the researcher Charles P. Auger, who wrote ''Use of Reports Literature'' in 1975. The literature he referred to consisted of intelligence reports and notes on atomic research produced in vast quantities by the Allied Forces during
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a World war, global war that lasted from 1939 to 1945. It involved World War II by country, the vast majority of the world's countries—including all of the gr ...
. In a conference held by the British Lending Library Division in 1978, Auger used the term "grey literature" to describe the concept for the first time. His concepts focused upon a "vast body of documents" with "continuing increasing quantity" that were characterized by the "difficulty it presents to the librarian". Auger described the documentation as having great ambiguity between temporary character and durability, and by a growing impact on scientific research. While acknowledging the challenges of reports literature, he recognized that it held a number of advantages "over other means of dissemination, including greater speed, greater flexibility and the opportunity to go into considerable detail if necessary". Auger considered reports a "half-published" communication medium with a "complex interrelationship
scientific journals". In 1989 Auger published the second edition of ''The Documentation of the European Communities: A Guide'', which contained the first usage of the term "grey literature" in a published work. The "Luxembourg definition", discussed and approved at the Third International Conference on Grey Literature in 1997, defined grey literature as "that which is produced on all levels of government, academics, business and industry in print and electronic formats, but which is not controlled by commercial publishers". In 2004, at the Sixth Conference in
New York City New York City (NYC), often simply called New York, is the List of United States cities by population, most populous city in the United States. With an estimated 2019 population of 8,336,817 distributed over about , New York City is also the L ...

New York City
, a postscript was added to the definition for purposes of clarification: grey literature is "...not controlled by commercial publishers, i.e., where publishing is not the primary activity of the producing body". This definition is now widely accepted by the scholarly community. The U.S. Interagency Gray Literature Working Group (IGLWG), in its "Gray Information Functional Plan" of 1995, defined grey literature as "foreign or domestic open source material that usually is available through specialized channels and may not enter normal channels or systems of publication, distribution, bibliographic control, or acquisition by booksellers or subscription agents". Thus grey literature is usually inaccessible through relevant reference tools such as databases and indexes, which rely upon the reporting of subscription agents. Other terms used for this material include: report literature, government publications, policy documents, fugitive literature, non-conventional literature, unpublished literature, non-traditional publications, and ephemeral publications. With the introduction of desktop publishing and the Internet, new terms include: electronic publications, online publications, online resources, open-access research, and digital documents. Though the concept is difficult to define, the term grey literature is an agreed collective term that researchers and information professionals can use to discuss this distinct but disparate group of resources. In 2010, D.J. Farace and J. Schöpfel pointed out that existing definitions of grey literature were predominantly economic, and argued that in a changing research environment, with new channels of scientific communication, grey literature needed a new conceptual framework. They proposed the "Prague definition" as follows: Due to the rapid increase web publishing and access to documents, the focus of grey literature has shifted to quality,
intellectual property Intellectual property (IP) is a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more than others. The most well-known types are copyright ...
, curation, and accessibility.

Publication types

The term ''grey literature'' acts as a collective noun to refer to a large number of publications types produced by organizations for various reasons. These include: research and project reports, annual or activity reports,
theses A thesis or dissertation (abbreviated diss.) is a document submitted in support of candidature for an academic degree or professional qualification presenting the author's research and findings.International Standard International Organizatio ...
conference proceedings In academia and librarianship, conference proceeding is a collection of academic paper Academic publishing is the subfield of publishing Publishing is the activity of making information, literature, music, software and other content availab ...
preprints In academic publishing, a preprint is a version of a scholarly or scientific paper that precedes formal peer review and publication in a peer review, peer-reviewed scholarly or scientific journal. The preprint may be available, often as a non-typ ...
working paper A working paper or work paper may be: *A preliminary scientific or technical paper. Often, authors will release working papers to share ideas about a topic or to elicit feedback before submitting to a peer review Peer review is the evaluati ...
newsletters A ''newsletter'' is a printing, printed or electronic publishing, electronic report containing news concerning the activities of a business or an organization that is sent to its members, customers, employees or other subscribers. Newsletters gene ...

, technical reports, recommendations and
technical standard A technical standard is an established norm (social), norm or requirement for a repeatable technical task which is applied to a common and repeated use of rules, conditions, guidelines or characteristics for products or related processes and product ...
patents NPOV disputes from March 2021 A patent is a title A title is one or more words used before or after a person's name, in certain contexts. It may signify either generation, an official position, or a professional or academic qualification. In ...
, technical notes, data and statistics, presentations, field notes, laboratory research books, academic courseware, lecture notes, evaluations, and many more. The international network GreyNet maintains an online listing of document types. Organizations produce grey literature as a means of encapsulating, storing and sharing information for their own use, and for wider distribution. This can take the form of a record of data and information on a site or project (archaeological records, survey data, working papers); sharing information on how and why things occurred (technical reports and specifications, briefings, evaluations, project reports); describing and advocating for changes to public policy, practice or legislation (white papers, discussion papers, submissions); meeting statutory or other requirements for information sharing or management (annual reports, consultation documents); and many other reasons. Organizations are often looking to create the required output, sharing it with relevant parties quickly and easily, without the delays and restrictions of academic journal and book publishing. Often there is little incentive or justification for organizations or individuals to publish in academic journals and books, and often no need to charge for access to organizational outputs. Indeed, some information organizations may be required to make certain information and documents public. On the other hand, grey literature is not necessarily always free, with some resources, such as market reports, selling for thousands of dollars. However, this is the exception and on the whole grey literature, while costly to produce, is usually made available for free. While production and research quality may be extremely high (with organizational reputation vested in the end product), the producing body, not being a formal publisher, generally lacks the channels for extensive distribution and bibliographic control. Information and research professionals generally draw a distinction between
ephemera Ephemera are any transitory written or printed matters that are not meant to be retained or preserved. The word derives from the neuter nominative etc. plural of the Greek ''ephemeros'', meaning "lasting only one day, short-lived", and it is thu ...

and grey literature. However, there are certain overlaps between the two media and they undoubtedly share common frustrations such as bibliographic control issues. Unique written documents such as
manuscript A manuscript (abbreviated MS for singular and MSS for plural) was, traditionally, any document written by hand – or, once practical typewriter A typewriter is a machine, mechanical or electromechanical machine for typing characters s ...

s and
archive An archive is an accumulation of Historical document, historical records – in any media – or the physical facility in which they are located. Archives contain primary source documents that have accumulated over the course of an individual o ...
s, and personal communications, are not usually considered to fall under the heading of grey literature, although they again share some of the same problems of control and access.


The relative importance of grey literature is largely dependent on research disciplines and subjects, on methodological approaches, and on the sources they use. In some fields, especially in the life sciences and medical sciences, there has been a traditional preference for only using peer-reviewed academic journals while in others, such as agriculture, aeronautics and the engineering sciences in general, grey literature resources tend to predominate. In the last few decades, systematic literature reviews in health and medicine have established the importance of discovering and analyzing grey literature as part of the evidence base and in order to avoid publication bias. Grey literature is particularly important as a means of distributing scientific and technical and public policy and practice information. Professionals insist on its importance for two main reasons: research results are often more detailed in reports, doctoral theses and conference proceedings than in journals, and they are distributed in these forms up to 12 or even 18 months before being published elsewhere. Some results simply are not published anywhere else. In particular, public administrations and public and industrial research laboratories produce a great deal of “grey” material, often for internal and in some cases “restricted” dissemination. The notion of
evidence-based policy Evidence-based policy (EBP) is an idea in public policy Public policy is a course of action created and/or enacted, typically by a government A government is the system or group of people governing an organized community, generally a ...
has also seen some recognition of the importance of grey literature as part of the evidence base; however, the term is not yet widely used in public policy and the social sciences more broadly.


For a number of reasons, discovery, access, evaluation and curation of grey literature pose a number of difficulties. Generally, grey literature lacks any strict or meaningful bibliographic control. Basic information such as authors, publication dates and publishing or corporate bodies may not be easily identified. Similarly, the nonprofessional
layout Layout may refer to: * Page layout, the arrangement of visual elements on a page ** Comprehensive layout (comp), a proposed page layout presented by a designer to their client * Layout (computing), the process of calculating the position of objec ...

s and formats, low print runs and non-conventional channels of distribution make the organized collection of grey literature a challenge compared to
journal A journal, from the Old French ''journal'' (meaning "daily"), may refer to: *Bullet journal, a method of personal organizations *Diary, a record of what happened over the course of a day or other period *Daybook, also known as a general journal, a ...
s and
book A book is a medium for recording information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature of its characteristics. The conc ...

s. Although grey literature is often discussed with reference to scientific research, it is by no means restricted to any one field: outside the hard sciences, it presents significant challenges in
archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. Archaeology is often considered a branch of socio-cultural anthropology, but archaeologists also draw from biological, geological ...
where site surveys and excavation reports, containing unique data, have frequently been produced and circulated in informal "grey" formats. Some of the problems of accessing grey literature have decreased since the late 1990s as government, professional, business and university bodies have increasingly published their reports and other official or review documents online. The informal nature of grey literature has meant that it has become more numerous as the technology that allows people to create documentation has improved. Less expensive and more sophisticated printers increased the ease of creating grey literature. And the ability to post documents on the internet has resulted in a tremendous boom. The impact of this trend has been greatly boosted since the early 2000s, as the growth of major search engines has made retrieving grey literature simultaneously easier and more cluttered. Grey reports are thus far more easily found online than they were, often at no cost to access. Most users of reports and other grey documents have migrated to using online copies, and efforts by libraries to collect hard-copy versions have generally declined in consequence. However, many problems remain because originators often fail to produce online reports or publications to an adequate bibliographic standard (often omitting a publication date, for instance). Documents are often not assigned permanent
URL A Uniform Resource Locator (URL), colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network A computer network is a group of computers that use a set of common communication prot ...
s or
DOI DOI or Doi may refer to: Science and technology * Digital object identifier, an international standard for document identification * Distinctness of image, a quantification of vision used in optics * 2,5-Dimethoxy-4-iodoamphetamine, a hallucinogeni ...
numbers, or stored in electronic depositories, so that
link rot Link rot (also called link death, link breaking, or reference rot) is the phenomenon of hyperlinks tending over time to cease to point to their originally targeted computer file, file, web page, or Server (computing), server due to that resource be ...
can develop within citations, reference lists, databases and websites.
Copyright Copyright is a type of intellectual property that gives its owner the exclusive right to copy and distribute a creative work, usually for a limited time. The creative work may be in a literary, artistic, educational, or musical form. Copyrigh ...

law and the copyrighted status of many reports inhibits their downloading and electronic storage and there is a lack of large scale collecting of digital grey literature. Securing long-term access to and management of grey literature in the digital era thus remains a considerable problem. The amount of digital grey literature now available also poses a problem for finding relevant resources and to be able to assess their credibility and quality given the number of resources now available. At the same time a great deal of grey literature remains hidden, either not made public or not made discoverable via search engines.


Various databases and libraries collect and make available print and digital grey literature; however, the cost and difficulty of finding and cataloguing grey literature mean that it is still difficult to find large collections. The
British Library The British Library is the national library A national library is a library A library is a curated collection of sources of information and similar resources, made accessible to a defined community for reference or borrowing. It provid ...

British Library
began collecting print grey literature in the post-WWII period and now has an extensive collection of print resources.
Analysis & Policy Observatory Analysis & Policy Observatory (more commonly known as APO) is a not-for-profit open access repository or digital library, specialising in public policy grey literature, mainly from Australia and New Zealand, with some coverage of other countries. Fo ...
has an extensive collection of grey literature on a wide range of public policy issues,
ArXiv arXiv (pronounced "archive"—the X represents the Chi (letter), Greek letter chi is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not Scholarly peer review, ...
is a collection of preprints on physics and other sciences, and RePEc is a collection of economics working papers. Many university libraries provide subject guides that give information on grey literature and suggestions for databases. ROAR and OpenDOAR are directories of open access
institutional repositories An institutional repository is an archive for collecting, preserving, and disseminating digital copies of the intellectual output of an institution, particularly a research institution.Van de Sompel, H & Lagoze, C. (2000. ''D-lib Magazine'', 6(2). ...
and subject repositories, many of which contain some grey literature. Several
academic search engines This article contains a representative list of notable databases and search engines useful in an academic setting for finding and accessing articles in academic journal An academic or scholarly journal is a periodical publication in which Scholarly ...
exist to combine the open data provided by such open archives through OAI-PMH, as well as records from publishers deposited in CrossRef and other sources. They include BASE (search engine), BASE, CORE (research service), CORE and Unpaywall, which indexes over 20 million open access publications as of 2020.

Resources and advocacy

The annual international grey literature conference series has been organized since 1993 by the Europe-based organization GreyNet. Research in this field of information has been systematically documented and archived via the International Conference on Grey Literature series. Grey Literature Network Service, Greynet also produces a journal on grey literature and has been a key advocate for the recognition and study of grey literature, particularly in library and information sciences, ''The Grey Journal''. ''The Grey Journal'' appears three times a year—in spring, summer, and autumn. Each issue in a volume is thematic and deals with one or more related topics in the field of grey literature. ''The Grey Journal'' appears both in print and electronic formats. The electronic version on article level is available via EBSCO's LISTA-FT Database (EBSCO Publishing). ''The Grey Journal'' is indexed by Scopus and others. On 16 May 2014, the ''Pisa Declaration on Policy Development for Grey Literature Resources'' was ratified and published.

See also

* Alternative media * European Association for Grey Literature Exploitation *Grey Literature International Steering Committee *Grey Literature Network Service * OpenSIGLE * System for Information on Grey Literature in Europe


Further reading

*Braun, Janice and Lola Raykovic Hopkins. "Collection-Level Cataloging, Indexing, and Preservation of the Hoover Institution Pamphlet Collection on Revolutionary Change in Twentieth Century Europe". ''Technical Services Quarterly'' 12:4 (1995): 1–8. *Cedefop; Eurolib. "EU grey literature: long-term preservation, access, and discovery". Luxembourg: Publications Office of the European Union, 2012. Available: *Childress, Eric and Erik Jul. "Going Gray: Gray Literature and Metadata". ''Journal of Internet Cataloging'' 6:3 (2003): 3–6. *Denda, Kayo. “Fugitive Literature in the Cross Hairs: An Examination of Bibliographic Control and Access”. ''Collection Management'' 27:2 (2002): 75–86. *D. J. Farace & J. Schöpfel (eds.) (2010). Grey Literature in Library and Information Studies. De Gruyter Sau

*Harrison, John. 200
Grey Literature or Fugitive Report Project
''MLA Forum'', 4(1). *Hirtle, Peter. 1991. Broadsides vs. Gray Literature. Available: I/msgOO02O.htm (June 15, 1997). *Information World. 1996. What is gray literature? Available:, (June 18, 1997). *Lawrence, A, Houghton J, Thomas J, and Weldon P 2014
''Where is the evidence: realising the value of grey literature for public policy and practice''
Swinburne Institute for Social Research. *P. Pejsova (ed.) (2010). Grey Literature Repositories. Radim Bacuvcik VeRBuM, Zlin C

*Schöpfel, Joachim. Observations on the Future of Grey Literature. ''The Grey Journal'' 2:2 (2006): 67–76. Available

(December 2009) *J. Schöpfel & D. J. Farace (2010). `Grey Literature'. In M. J. Bates & M. N. Maack (eds.), Encyclopedia of Library and Information Sciences, Third Edition, pp. 2029–2039. CRC Press. *Seeman, Corey. "Collecting and Managing Popular Culture Material: Minor League Team Publications as "Fringe" Material at the National Baseball Hall of Fame Library". ''Collection Management'' 27:2 (2002): 3–20. * *Sulouff, P., et al. Learning about gray literature by interviewing subject librarians: A study at the University of Rochester. ''College & Research Libraries News'', 66(7) 2005, pp. 510–515. * White, Herbert. 1984. ''Managing the Special Library''. White Plains, N. Y.: Knowledge Industries Publications, Inc.

External links

About grey literature in medical systematic reviews

The Grey Literature Network Service
is a gateway to over 50 million pages of authoritative selected science information provided by U.S. government agencies, including research and development results. * Science Accelerator searches science, including R&D results, project descriptions, accomplishments, and more, via resources made available by the Office of Scientific and Technical Information (OSTI), U.S. Department of Energy
The GrayLIT network: A science portal of technical reports
From the Office of Scientific & Technical Information at the United States Department of Energy.
Grey Literature Library for UK Archaeology
* The

''published one volume in 2000. The content may be limited to subscribers.
OpenGrey Repository, formerly OpenSIGLE
{{Authority control Grey literature, Technical communication Publishing