Comprehensive report using explicit processes so that rationale, assumptions and methods are open to scrutiny by external parties.Collates all that is known on a given topic and identifies the basis of that knowledge.Identifies, appraises and synthesizes all available research that is relevant to a particular review question.May include a meta-analysis (quantitative synthesis) *optional.Explicit methods of extracting and synthesizing study findings (qualitative or quantitative).Application of established standards to critically appraise study quality.Use of explicit criteria to include / exclude studies.Comprehensive search to find all relevant studies.The scope of the review is identified in advance (eg review question and sub‐questions and/or sub‐group analysis to be undertaken).Biases that occur in selecting and assessing the literature are unknown.The writers assumptions and agenda often unknown.To scope the types of interventions available to include in a review.Often used as rationale for new research.

Overviews, discussions, critiques of previous work and the current gaps in knowledge.Describes and appraises previous work but does not describe specific methods by which the reviewed studies were identified, selected and evaluated.Traditional literature review / narrative review:

Another word for previous studies