Assessment of what is already known about a policy or practice issue, by using systematic review methods to search and critically appraise existing research.
SEARCH is determined by time constraints.
APPRAISAL is a time-limited formal quality assessment.
SYNTHESIS is narrative and tabular.
ANALYSIS includes quantities of literature and overall quality/direction of effect of literature.
Source: A typology of reviews: an analysis of 14 review types and associated methodologies. Grant MJ & Booth A. Health information and Libraries Journal year: 2009 26(2):91 -108. doi: 10.1111/j.1471-1842.2009.00848.x.