Grey literature

Evaluating grey literature

Grey literature usually doesn't go through the formal peer review process that other research does. This means the reliability of the information can vary. This makes it very important to evaluate the quality of grey literature. 

When evaluating preprints, consider these additional elements: 

• potential for bias in the study design 
• reputation of the preprint server 
• peer review status of the preprint.  

Appraisal tools

Appraisal tools exist for specific study types such as randomised controlled trials and other types of clinical trials. The same tools apply whether they are published or unpublished.  

While there are no specific appraisal tools for grey literature generally, the AACODS checklist considers key elements for reviewing grey literature other than clinical trials. These include the authority of the creator and the sharing organisation, accuracy and objectivity of the content, date of creation and significance of the content. 

• AACODS checklist
  an Australian grey literature appraisal checklist
   
• CASP Randomised Controlled Trial checklist
  appraisal tool for a specific type of clinical trial (published and unpublished)
   
• JBI policy appraisal tool
  tools from the Joanna Briggs Institute
   
• Risk of bias tools
  a series of appraisal tools for different types of clinical trials