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How to find grey literature

Planning your search for grey literature

Many Library databases include grey literature. Searching additional sources and using other search approaches will make your searching more comprehensive, reducing the chance that you miss anything crucial. To be systematic, adapt the search strategy that you developed for your core database search, and ensure that your approach is transparent and reproducible where possible.

The Library's Guides provide links to discipline specific information sources such as databases, organisations, and more. 

How to find grey literature

Technique Description
Expand your search to other databases Some databases index material that is traditionally regarded as 'grey' literature, such as theses and reports
Undertake citation searching Check reference lists of reports of included studies ('backwards citation searching') and research outputs that have cited these reports in turn ('forwards citation searching')
Identify key authors and experts The author profiles of researchers working in the area may reveal further avenues (studies, organisations, contacts, etc.). Experts may be able to provide guidance
Undertake 'hand searching' View issues of relevant journals or conference proceedings
Examine relevant clinical guidelines These high quality summaries designed to assist health professionals make clinical decisions about appropriate health care can be a valuable source of studies
Search trials registers Locate ongoing or unpublished studies
Consult conference materials Conference material can be a source of the latest research and contain references to studies that are ongoing or for which outcomes were never formally published
Identify key organisations Identify government agencies, peak bodies, research institutes and other organisations relevant to your area of interest
Undertake web searching Use search engines, catalogues, portals, directories, and other tools to locate further material. Search websites of key organisations

Note: terminology has changed over time, and rather than using 'pearling' and 'snowballing' this is now more commonly referred to as backward citation searching (also known as reference list checking) and forward citation searching.

Finding grey literature can be difficult and time consuming.

Grey literature often:

  • is not classified, catalogued, indexed or archived
  • is not stored in a retrievable format
  • is not available electronically
  • has short print runs which may lead to lack of availability
  • has inconsistent format and citation information
  • has a large volume of material which may be overwhelming
  • has variation in evidence quality.

These challenges can make relevant information virtually impossible to find and eventually invisible.

Guidelines and standards

Dedicated to grey literature

A selection of organisations, portals and tools that focus on grey literature: