Gray Literature

Grey literature (or gray literature) is a library and information science term that refers to written material (such as reports) that is difficult to find via conventional channels such as published journals and monographs because it is not published commercially or isn't generally accessible. It is considered an important source of information, however, because it tends to be original and recent. Examples of grey literature include patents, technical reports from government agencies or scientific research groups, working papers from research groups or committees, white papers, and preprints.

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, nonprofessional layouts and formats and low print runs of grey literature make the organized collection of such publications challenging compared to journals and books.

Information and research professionals generally draw a distinction between ephemera and grey literature. However, there are certain overlaps between the two media and they certainly share common frustrations such as bibliographic control issues. Although the term is often employed with scientific research in mind, grey literature is not specific to one field.

Many of the problems of initially or temporarily accessing the 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 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 and accessed online now than a decade ago, 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 print 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 URLs or DOI numbers, nor stored in electronic depositories, so that broken links can develop; and because the copyright status of most 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.