Which statement best differentiates grey literature from traditional published literature in research reviews?

Which statement best differentiates grey literature from traditional published literature in research reviews?

• A. Grey literature includes reports, theses, and preprints not controlled by major publishers and can reduce publication bias.
• B. Grey literature does not include theses or preprints.
• C. Grey literature is always peer-reviewed.
• D. Grey literature cannot contribute to systematic reviews.

Answer: (A)

Grey literature consists of materials not produced or controlled by major publishers, such as reports, theses, conference papers, government documents, and preprints. Because these items aren’t limited to the traditional publishing pathway, they’re often not captured in standard databases, and they may include studies that journals might not publish, especially if results are negative or inconclusive. Including grey literature in a review helps counter publication bias by broadening the evidence base beyond what appears in conventional journals. In contrast, traditional published literature is typically peer-reviewed and widely indexed, which can skew the visible evidence toward positive or favorable results. That’s why this statement best differentiates grey literature: it highlights the absence from major publishing control and its potential to reduce publication bias.

Grey literature consists of materials not produced or controlled by major publishers, such as reports, theses, conference papers, government documents, and preprints. Because these items aren’t limited to the traditional publishing pathway, they’re often not captured in standard databases, and they may include studies that journals might not publish, especially if results are negative or inconclusive. Including grey literature in a review helps counter publication bias by broadening the evidence base beyond what appears in conventional journals. In contrast, traditional published literature is typically peer-reviewed and widely indexed, which can skew the visible evidence toward positive or favorable results. That’s why this statement best differentiates grey literature: it highlights the absence from major publishing control and its potential to reduce publication bias.