© 2009 The authors Journal compilation © 2009 Health Libraries Group. Health Information and Libraries Journal, 26, pp.91–108 91 DOI: 10.1111/j.1471-1842.2009.00848.x Blackwell Publishing Ltd Review Article A typology of reviews: an analysis of 14 review types and associated methodologies Maria J. Grant* & Andrew Booth†, *Salford Centre for Nursing, Midwifery and Collaborative Research (SCNMCR), University of Salford, Salford, UK, †School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK Abstract Background and objectives: The expansion of evidence-based practice across sectors has lead to an increasing variety of review types. However, the diversity of terminology used means that the full potential of these review types may be lost amongst a confusion of indistinct and misapplied terms. The objective of this study is to provide descriptive insight into the most common types of reviews, with illustrative examples from health and health information domains. Methods: Following scoping searches, an examination was made of the vocabulary associated with the literature of review and synthesis (literary warrant). A simple analytical framework—Search, AppraisaL, Synthesis and Analysis (SALSA)—was used to examine the main review types. Results: Fourteen review types and associated methodologies were analysed against the SALSA framework, illustrating the inputs and processes of each review type. A description of the key characteristics is given, together with perceived strengths and weaknesses. A limited number of review types are currently utilized within the health information domain. Conclusions: Few review types possess prescribed and explicit methodologies and many fall short of being mutually exclusive. Notwithstanding such limitations, this typology provides a valuable reference point for those commissioning, con- ducting, supporting or interpreting reviews, both within health information and the wider health care domain. Background The advent of evidence-based practice (EBP) in the early 1990s has seen the role of the health library and information worker in the ascendancy, with clinicians increasingly relying on health care literature in their decision making. With their knowledge of information sources and their skills to retrieve information to inform health care decisions, library and information sector workers have played, 1 and indeed continue to play, an important role in assisting in the uptake of EBP principles and practice. It quickly became apparent that synthesized summaries of ‘all’ evidence within a particular domain would be required, in addition to the evidence from primary studies, if clinicians were to make truly informed decisions within a typical consultation. However, the review article of the time seemed ill-equipped to meet such a challenge. Medical review articles of the pre-EBP era were generally unsystematic and lacked formal statistical methods to derive best estimates of treatment effects from the available Correspondence: Maria J. Grant, Salford Centre for Nursing, Midwifery and Collaborative Research, School of Nursing, University of Salford, Salford M6 6PU. E-mail: m.j.grant@salford.ac.uk