What is grey literature?

'Grey literature stands for manifold document types produced on all levels of government, academia, 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.'
(Schöpfel, 2010)

Grey literature includes: 

• reports (government and non-government)
• organisation websites or publications from organisations - including brochures, leaflets, fact sheets & bulletins
• policy documents, working papers, technical reports
• patents
• theses & dissertations
• conference proceedings
• clinical trials
• surveys, interviews & personal communications
• census & other data & statistics sources
• respositories & digital libraries eg e-print or pre-prints of articles, theses, research reports
• blogs, podcasts & video
• social media networks (Twitter, wikis etc).

To evaluate grey literature use the AACODS checklist.

 Sources for grey literature:

• University of Otago Library Grey literature in health guide includes sources for clinical trials and guidelines. (bpac has guidelines for New Zealand 2015 onwards bpac guidelines)

• Canadian Agency for Drugs and Technologies in Health (CADTH)
  • Grey Matters: a practical search tool for evidence-based medicine
  • Covid-19 Grey Literature Resources

See also:

• Theses and dissertations
• Conferences and proceedings
• The Hub from SIA (Social Investment Agency) for New Zealand focused social science research  and reports undertaken, commissioned or at least partly funded by central government in New Zealand. Some reports still at Superu which operated 2004-2018 and closed on 30th June 2018 under the Families Commission Act Repeal Act.
• Analysis and Policy Observatory - mainly Australian policy documents but one of the collections is New Zealand governance and policy. Also see Koi Tu a transdisciplinary centre based at the University of Auckland.
• Think Tank Search from Harvard Kennedy School Library and Knowledge Services
• PsycEXTRA - a full-text grey literature American Psychological Association resource, which includes conference papers, technical and government reports, newsletters, magazines and other non-peer-reviewed material
• Systematic reviews done by:
  • Campbell Collaboration
  • EPPI Centre (Evidence for Policy and Practice Information and Co-ordinating Centre).
  • Joanna Briggs Institute for nursing
  • (NZ) Health Services Assessment Collaboration
• Health Technology Assessments - See Centre for Reviews and Dissemination database and the NIHR HTA database
• Clinical trials
  
  • Clinical trials registers and regulatory databases from the Cochrane Collaboration. Includes import filters for EndNote - A useful resource to start you on your way.
  • York Health Economics Health Consortium Finding clinical trials, research registers and research results
    
    Trials websites:
  • University of Leeds Library has a comprehensive list
  • University of Otago Library - Clinical Trials segment of their Grey Literature guide.
  • Section 6.2.3 Unpublished and ongoing studies in the Cochrane handbook has lists and links to national and pharmaceutical company trial registers
  • ClinicalTrials.gov
  • WHO International Clinical Trials Registry Platform (ICTRP) NOTE keep your search really basic.
  • Australian New Zealand Clinical Trials Registry
  • ANZICS current active endorsed research
  • Alltrials 'international initiative of Ben Goldacre, BMJ, Centre for Evidence-based Medicine, Cochrane Collaboration, James Lind Initiative, PLOS and Sense about Science'
  • OpenTrials 'locate, match, and share all publicly accessible data and documents, on all trials conducted, on all medicines and other treatments, globally' - collaboration between Open Knowledge International and Dr Ben Goldacre from the University of Oxford DataLab
  • Clinical Trials preprints on BioRxiv
  • ALOIS - From the Cochrane Dementia and Cognitive Improvement group 'controlled trials that have been completed, are ongoing or are planned in the areas of dementia (prevention and treatment), mild cognitive impairment and cognitive improvement...updated every month from searches of a wide range of databases and clinical trials registries, with the help of a team of volunteers'.
  • EU clinical trials register
  • UK clinical trials gateway includes registered, recruiting and completed trials
  • Chinese Clinical Trial Registry
  • UMIN Clinical Trials Registry (Japan)
  • Dimensions - filter results to Clinical Trials
  • RIAT Studies (Restoring Invisible and Abandoned Trials)
  • Trials Transparency - FYI - Trials tracker including links to FDAAA and EU trials
  • ClinicalStudyDataRequest.com
• FDA (US) Drug approvals and database
• European Medicines Agency Clinical data
• Clinical Study Reports. These are documents prepared and submitted to regulators to obtain a marketing licence for a pharmaceutical. See the 2 above resources plus sources in Jefferson T, Doshi P, Boutron I et al. When to include clinical study reports and regulatory documents in systematic reviews. BMJ Evidence-Based Medicine, 2018;23:210-217.
• NIDA International Drug Abuse Research Abstract DatabaseNIH National Institute on Drug Abuse
• Health Canada: Clinical information on drugs and health products
• Patents at LENS.ORG
• Ministry of Health Grey matter newsletter
• OpenDOAR Directory of Open Access Respositories
• Preprint sites eg medRxiv
• OpenGrey
• The University of Auckland library guide for Statistics and numeric data
• government, NGO, research institute, think tank, & professional college websites eg Kings Fund, World Bank Open Knowledge Repository.

Systematic reviews and grey literature:

Mahood Q, Eerd DV, Irvin E. Searching for grey literature for systematic reviews: challenges and benefits. Research Synthesis Methods. 2014;5(3):221-34.

Schöpfel, J. (2010. Towards a Prague definition of grey literature. Paper presented at the Twelfth International Conference on Grey Literature: Transparency in Grey Literature. Grey Tech Approaches to High Tech Issues, Prague, 6-7 December 2010. Retrieved from http://archivesic.ccsd.cnrs.fr/sic_00581570