ABSTRACT
When writing a meta-analysis, the rst step is to perform a literature review with respect to the clinical question. As with writing a clinical topic review (CTR), a literature review should include all the common databases, relevant papers from the references of papers that have already been chosen and a review of the grey literature. Grey literature is data that is not easily available and could include unpublished studies, conference abstracts, and drug company promotional material. How and where the authors of the paper have searched must be explicitly stated.
