Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Searching for and using grey literature

  • Comment

VOL: 102, ISSUE: 50, PAGE NO: 35-36

This article aims to provide nurses with a practical guide to searching for and making use of grey literature in their research and reports.

Looking for a job in healthcare?

Nursing Times Jobs has thousands of current vacancies




Coad J et al (2006) Searching for and using ‘grey’ literature. Nursing Times.netAim

We have drawn on our own experiences as writers for reports and publications and from the submission of assignments.

This article outlines the best way to search for and use grey literature from a variety of sources including oral presentations and personal communication, leaflets, newspaper and magazines, unpublished research, internal reports and minutes of meetings.

There is an ever-growing amount of grey literature available to nurses and with the right approach it can be an invaluable resource. The use both published and unpublished literature has grown immensely in the past 20 years. Literature that is ‘semi-published’, is not published and/or is not available through the usual bibliographic sources such as databases or indexes is known as grey literature. It is often information that has been conveyed by another route such as an oral presentation or an internal report.


What sources are included?

Auger (1994) notes that sources of grey literature include all types of literature that are not available through the normal book selling channels, including reports, trade literature, translations and ad hoc publications.Thus, there is an immense range of grey literature including, but not limited to, brochures, pamphlets, internal reports, memoranda, reports and assignments. Sources can also be oral, in print form and, increasingly, electronic formats.



Jane Coad, PhD, BSc, PGDip, RGN, RSCN, is senior research fellow at the University of Bristol Centre for Child and Adolescent Health; Jayne Hardicre, MSc, BSc, RN(A), is lecturer in nursing, University of Salford; Patric Devitt, MSc, BA, RGN, RSCN, is senior lecturer, University of Salford.


Table 1 details a selection of the most common sources of grey literature.

Oral PresentationsTables/ImagesWritten informationReports Media Research Letters
Conference proceedings, abstracts and presentationsAudio-visual materialsInternal and technical reportsNewspapersUnpublished dissertations and thesisDiaries
Lectures, seminars and tutorialsDiagrams,tablesCommittee reportsTelevision/web-basedResearch - completed and in progressLetters
SymposiaMusic (sound images)Business reportsEditorials Memoranda
Informal communications such as telephone conversations and ad hoc meetingsModels/frameworksFormal meetings (with minutes)Magazines Trade literature or brochures
 PhotographsTranslations  Pamphlets
 Art pictures and postersAssignments  Bulletins
 Film and videoCensus reports  Leaflets

Table 1. Sources of grey literature


Why is it important?

Grey literature is an important source of information and arguably may become more important as the flow of information across the world continues to spread (Lawrence and Giles, 1999). According to Farace (1997) the rate of growth of grey literature is three to four times that of conventional literature. Although grey literature may not be scholarly or peer-reviewed, it is often produced by researchers and practitioners who have drawn on their experience. It can often be produced relatively quickly so is often very up to date, has much flexibility in application and is often more detailed than other types of literature. Published work on the other hand is often subject to restrictions such as a limited word count. However, there are also common pitfalls in searching for and using grey literature, some of which will be covered in this article.


Finding grey literature

Searching for grey literature can be difficult for a number of reasons. Grey literature tends to be difficult to control bibliographically, in that some pieces will lack proper titles or descriptive information, making classification or cataloguing challenging. This said, most libraries will have a collection of some grey literature in stock but again this may be variable because some librarians are hesitant to add grey literature to their catalogues for practical reasons (it can be difficult to store and it’s vast nature makes it difficult to source/catalogue). The simplest solution is to ask your librarian for more information on what is available in your library. Also most institutions, NHS trusts, primary care trusts (PCTs), companies, industries and resource centres will have a certain amount of grey literature available, for example, pamphlets and brochures available in a health centre.


The internet

Searching can be costly, especially in terms of time, but this is undoubtedly made a great deal easier if you have access to the internet. The internet is now a major source of dissemination and retrieval of grey literature and often serves as the initial introduction to your subject or topic area. As costs increase, researchers are publishing and disseminating their work through different channels, such as the internet, desk-top publishing packages and portable document files (PDF). These help to reduce publishing costs, but the challenge is to keep web sites up-to-date, well indexed and navigable.

Scientific publishing on the World Wide Web has made it possible to disseminate new information to a global audience in a matter of minutes. The search engine Google ( enables users to search for PDF files, and for information within PDF files which has improved the facility for and increased the speed of searching for relevant papers and reports. Indeed, searching for web sites under the relevant subject heading while linking the key words of ‘grey literature’ and a wealth of information is instantly revealed. But, users need to be aware that these resources can change rapidly so it is important to ensure relevant websites are saved immediately in ‘favourites’ and the full internet address is recorded, including the date that the resource was accessed. This process authenticates the sources for future use and referencing. Internet gateways can be used to access specific databases from which published and grey literature can be obtained. Details for finding specific grey literature, including web addresses are outlined in Hart (2001). Substantial amounts of information can be found in the System for Grey Literature in Europe (SIGLE) which organises grey literature by subject area and is produced by the European Association for Grey Literature (EAGLE). The Open University also have a dedicated grey literature site with useful information about key references on using grey literature ( GreyNet (Grey Literature Network Service) was established in the Netherlands in 1992 and has an immense collection of bibliographies and information about using grey literature work. Further information can be found in the New York Academy of Medicine grey literature website (, which is particularly useful for medical and health science related grey literature. The website includes a list of grey literature producing organisations and has a quarterly report listing new resources. Table 2 illustrates a range of databases and search engines, and whilst this is not an exhaustive list, it includes useful sources that incorporate grey literature. If you type in any of these it will take you through the homepage to an array of grey literature.


Search Adobe PDF Online
BLDS Database (British Library for Development Studies)
BIREME Databases
CABOT (Canadian Research Database)
CMA Infobase (Canadian Clinical Practice Guidelines)
CoGPrints e-archive
Competitive Intelligence Databases (CISTI)
CRISP database
DARE (Database of Abstracts of Reviews of Effects)
DIMDI databases
Directory Database of Research (JAPAN)
Dissertation Abstracts
ERIC database
GrayLit Network
HMIC: Health Management Information Consortium
HTA Database
ISI (Index to social and humanities proceedings)
Microlog (Subscription Only)
National Guidelines Clearinghouse
National Research Register (UK)
Netprints (BMJ)
Networked Digital Library of Theses
Social Care On line
SIGLE (System for Information on Grey Literature in Europe)(Subscription only)
WorldCat (subscription only)

Table 2. Useful databases and search engines


Obvious sources of oral information are conference proceedings, symposia, abstracts and presentations, lectures, seminars and tutorials. But this category also includes informal communications such as telephone conversations and ad hoc meetings. If you have heard an oral presentation, for example, at a conference or lecture you may find that the speaker provides supportive literature (many conferences and/or lectures are now loaded into the web so are more accessible). If, however, you wish to obtain a paper following an event you can do this in several ways. Firstly, use a database such as ISI (Index to social and humanities proceedings) or Boston Spa (BLDSC) both of which have thousands of titles and conference proceedings. Other routes might be to contact the organisers via the conference information. Some conference units may ask for a small charge to send previous papers and proceedings. Finally, you could ask the speaker directly. If you do this ensure that you tell them that you will acknowledge their work in your intended piece. Also, if it is a face to face meeting or telephone conversation try to ask permission at the time as this may facilitates a more positive result than if the request comes several weeks later.


In the strictest sense, image-related information is not literature as such, but can be used in your grey literature searching strategy in order to underpin your thinking. There are thousands of sources of image-related information, which are updated regularly and a general Google or Yahoo search is a good place to start. Image-related information includes audio-visual materials, art, films, video, diagrams, tables, music, photographs, posters and frameworks. However, it is important to be selective about using the work as there may be limited critical discussion about the material. But image-related information can often provide a basis for the rest of your work. We recommend that you begin the search with your focus such as film or art but link it to the words of collections, indexing, library and/or databases. WRITTEN INFORMATIONWritten information includes internal reports; minutes from formal meetings, newspapers, magazines, unpublished theses, research in progress, letters, diaries, memos, leaflets and bulletins. We have found this type of grey literature to be most valuable as many pieces contain excellent information at the forefront of current and original thinking. You can find written literature through a variety of sources such as higher education institutions, organisations such as the Royal College of Nursing, voluntary or pressure groups such as Macmillan and the British Library. Although abstracts and short pieces are generally easy to obtain getting hold of a full copy of the work can often be a major problem. The higher education institutions have copies of all their student theses on microfiche which can be very helpful. USING GREY LITERATUREA critical issue in using grey literature is the quality and value of information available and the lack of peer-review (Hart, 2001; Egger et al, 2003). In using any grey literature you must be prepared to carefully evaluate when it was written, by whom and its purpose. The piece also must be available to others, such as a reader, assessor, delegate or reviewer. Some writers overcome this problem by including the piece as an appendix. REFERENCINGLike any reference source you must include all the details of grey literature you have used in your reference/bibliography lists in order to authenticate the information. You will need to include the original author details, any dates (or approximate if absent) and full titles. You should also include that the piece is unpublished and/or the format such as a dissertation, leaflet or personal communication. If you download information from the internet you need to include the date this was accessed because of rapid turnover of web-based materials. If the piece is an image you should identify the sources within the heading title, but you can note that the piece is ‘adapted from’ if you had to re-draw the image or table. Remember if your work which makes use of grey literature is published you must seek the original authors’ permission.


There are a number of ways to search, identify and make use of grey literature in your research and reports. Undoubtedly, the amount of grey literature is ever increasing and it can be an invaluable source.



Auger, C.P. (1990) Information sources in grey literature. London: Bowker-Saur.

Egger, M. et al (2003) How important are comprehensive literature searches and the assessment of trial quality in systematic reviews? Health Technology Assessment; 7(1).

Farace, D.J. (1997) Rise of the phoenix: a review of new forms and exploitations of grey literature. Pub ResQ; 13, 2: 69-76.

Goodman, C. (1993). Literature searching and evidence interpretation for assessing health care practices. Stockholm: The Swedish Council on Technology Assessment in Health Care.

Hart, C. (2001) Doing a literature search. London: Sage Publications.

Helmer, D. (2004) Grey literature. In: Etext on health technology assessment (HTA) information resources.

Lawrence, S., Giles, L. (1999) Accessibility of information on the web. Nature. 400: 6740: 107-9.

Open University (2006) Reports and grey literature.



  • Comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Links may be included in your comments but HTML is not permitted.