Grey literature Grey literature is informally published written material ( such as reports ) that may be difficult to trace via conventional channels such as published journals and monographs because it is not published commercially or is not widely accessible . It may nonetheless be an important source of information for researchers , because it tends to be original and recent . Examples of grey literature include patents , technical report s from government agencies or scientific research groups , working papers from research groups or committees , white papers , and preprint s . The term " grey literature " is used in library and information science . The identification and acquisition of grey literature poses difficulties for librarians and other information professionals for several reasons . Generally , grey literature lacks strict bibliographic control , meaning that basic information such as author , publication date or publishing body may not be easily discerned . Similarly , the nonprofessional layout s and formats , low print runs , and non - conventional channels of distribution of grey literature make the organized collection of such publications challenging compared to journals and books . In 1995 , D . B . Simpson observed that " peripheral materials , including grey literature , expand unabated . Libraries having difficulty collecting traditional materials have little hope of acquiring the periphery " . Information and research professionals generally draw a distinction between ephemera 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 manuscripts and archive s , and personal communications , are not usually considered as falling under the heading of grey literature , although they again share some of the same problems of control and access . Although grey literature is often discussed with reference to scientific research , it is by no means restricted to a single field : outside the hard sciences , it presents significant problems in , for example , archaeology , in which site surveys and excavation reports , containing unique data , have frequently been produced and circulated in informal " grey " formats . Many 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 free on the World Wide Web . The impact of this trend has been greatly boosted since the early 2000s by the growth of major search engines such as Google , Yahoo ! and Bing . Grey reports are thus far more easily found online than they were , and at radically lower cost , at least in the immediate aftermath of their publication . 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 document online reports or publications adequately ( often omitting a publication date , for instance ) ; because documents are rarely assigned permanent URL s or DOI numbers , or stored in electronic depositories , so that broken links can develop ; and because the copyright status of many reports is left unclear , inhibiting their downloading and electronic storage . Securing long - run or secure access to grey literature in a predominantly digital age thus remains a considerable problem , as does archiving or overviewing such materials . Definitions . The concept of grey literature has emerged since the 1970s . When Charles P . Auger published the first edition of his landmark work on " reports literature " in 1975 , he did not use the term " grey literature " . Nevertheless , his account of this " vast body of documents " , with its " continuing increasing quantity " , the " difficulty it presents to the librarian " , its ambiguity between temporary character and durability , and its growing impact on scientific research , was entirely compatible with what is now called grey literature . While acknowledging the challenges of reports literature , he also 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 " . For Auger , reports were a " half - published " communication medium with a " complex interrelationship [ to ] scientific journals " . Only in the second edition of his book , published in 1989 , did he adopt the term " grey literature " . The so - called " 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 , a postscript was added 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 has since been widely accepted , by , among others , the Grey Literature Network Service . It emphasizes the supply side of grey literature , namely its production and publication both in print and electronic formats . It calls attention to the question of dissemination , and the difficulty of identifying and accessing documents described as ephemeral , non - conventional or underground . 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 " . This definition accords with Mackenzie Owen ’ s 1997 observation that " grey does not imply any qualification [ but ] is merely a characterization of the distribution mode " . 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 , and with new channels of scientific communication , grey literature needed a new conceptual framework . Towards a new definition . The 12th International Conference on Grey Literature at Prague in December 2010 discussed a new approach to grey literature . It concluded that the existing definition of grey literature — the New York definition — remained helpful and should not be replaced , but that it needed to be adapted to the changing environment . The definition was insufficient in the context of Internet publishing , and that further attributes were needed to differentiate grey from other items . The proposal was to add four attributes to the New York definition : The proposal for a new definition ( " Prague Definition " ) of grey literature is as follows : " Grey literature stands for manifold document types produced on all levels of government , academics , business and industry in print and electronic formats that are protected by intellectual property rights , of sufficient quality to be collected and preserved by library holdings or institutional repositories , but not controlled by commercial publishers i . e . , where publishing is not the primary activity of the producing body . " Today , due to the overwhelming success of web publishing and access to documents focus has shifted to quality , intellectual property , and intermediation . Without the revision mentioned above , the current definition risks becoming obsolete due to its inability to differentiate grey literature from other documents . The proposal for a revised “ Prague definition ” brings together the former economic approach with new attributes . The next step should be to check this definition against common usage in libraries and different types of grey and other documents . Once done , the value of the definition can be evaluated on the basis of the answers to the following two questions : does this new definition include all kind of documents usually considered by LIS professionals as grey literature , including today ’ s difficult - to - process and hard - to - collect items , and does it lead to further differentiation or better understanding of how grey literature may be distinguished from other forms of literature ? Three challenges in particular are said to face professionals in the field at the present moment : Typology of grey literature . The term traditionally referred to reports , conference proceedings and doctoral theses . In the OpenSIGLE repository , reports are the most numerous among the different types of grey literature . The " reports " category covers a wide variety of very different documents : institutional reports , annual or activity reports , project or study reports , technical reports , reports published by ministries , laboratories or research teams , etc . Some are disseminated by national and international public bodies ; others are confidential , protected , or disseminated to a restricted readership , such as technical reports from industrial R & D laboratories . Some are voluminous , with statistical appendices , while others are only a few pages in length . In the other categories , citation analyses offer a wide range of grey resources . Besides theses and conference proceedings , they also include unpublished manuscripts , newsletters , recommendations and technical standard s , patents , technical notes , product catalogs , data and statistics , presentations , malin - grey literature , personal communications , working paper s , house journals , laboratory research books , preprints , academic courseware , lecture notes , and so on . The international network GreyNet maintains an online listing of document types . Malin - grey literature . " Malin - grey literature " refers to publications whose construction and self - referencing are actively construed to avoid the attention of information professional s . Typically such professionals employ various parameters in identifying which publications are suited to incorporation within a particular collection . To avoid dissemination and archiving the authors of malin - grey literature employ the absence of bibliographical indicators , deception , disinformation , rapid decomposition ( or other self - destructive construction ) , obscurity or atypical formats . Malin - grey literature differs from samizdat , or underground literature , in that samizdat publications only seek to disguise the identities of the author and distributor , whereas malin - grey literature seeks actively to prevent or obstruct dissemination . Some commentators have suggested that the name derives from the French for " deceptive ingenuity " ; others , less convincingly , claim that it is a reference to Anne - Marie Malingrey ( fl . 1960s - 70s ) , a French historian . Impact . Grey literature has a role of its own as a means of distributing scientific and technical 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 . A Franco - Dutch study reviews 64 citation analyses published between 1987 and 2005 , citing altogether several thousand references . The table below shows the proportion of grey literature cited in publications from different scientific disciplines . The relative importance of grey literature is largely dependent on research disciplines and subjects , on methodological approaches , and on sources used . In some fields , especially the life sciences and medical sciences , there has been a traditional preference for conventional distribution media ( journals ) , while in others , such as agriculture , aeronautics and the engineering sciences in general , grey literature resources tend to predominate . 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 . According to another study , grey literature seems also to play a considerable part in the library and information sciences , accounting on average around 20 % of all sources used a figure that may be compared with the citation habits in economics and educational sciences . Even so , citations to grey material vary widely between different papers from 0 % to 50 % and more , depending on subject areas and methodologies . Grey Literature International Steering Committee . The Grey Literature International Steering Committee ( GLISC ) was established in 2006 after the 7th International Conference on Grey Literature ( GL7 ) held in Nancy ( France ) on 5 – 6 December 2005 . During this conference , the Istituto Superiore di Sanità ( ISS ) ( Rome , Italy ) presented guidelines for the production of scientific and technical reports included in the wider category of grey literature . The Italian initiative for the adoption of uniform requirements for the production of reports was discussed during a Round Table on Quality Assessment by a small group of grey literature producers , librarians and information professionals who agreed to collaborate in the revision of the guidelines proposed by ISS . The group approving these guidelines – informally known as the " Nancy Group " – has been formally defined as the Grey Literature International Steering Committee . The Guidelines include ethical principles related to the process of evaluating , improving , and making reports available and the relationships between grey literature producers and authors . The latter sections address the more technical aspects of preparing and submitting reports . GLISC believes the entire document is relevant to the concerns of both authors and grey literature producers . GreyNet resources . Since 1993 , GreyNet International , the Grey Literature Network Service , organizes the International Conferences Series on Grey Literature : GreyNet also organizes GreyWorks , a summer workshop series on grey literature : GreyNet likewise publishes an academic journal on grey literature , " The Grey Journal " ( print : , online : ) . 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 . Perspectives . In the ongoing discussion on new business models of academic publishing , eScience and open access to public research results , non - commercial distribution channels will continue to play a central role as vectors of scientific communication , alongside commercial publishing . Another question is about impact and usage . In the past , impact metrics were limited to citations and journals . Today , usage metrics offer new opportunities to measure impact of a large scale of digital resources , also on the individual item level . Tomorrow , these metrics will provide additional information on quality and popularity to the end user . Open archive s will offer more appropriate services and functions for at least some segments of grey literature if not for all . But bibliographic control of grey literature will remain problematic despite the trend toward standardization of digital documents . And the libraries , together with their scientific communities , need to find new forms for the fundamental functions of scientific publishing , applied to open repositories , non - commercial items and datasets .