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Systematic Reviews & Evidence Synthesis Methods

This is a guide to understanding systematic reviews and other evidence synthesis methods. Links to resources and information about the Libraries' Systematic Review Service is included.

More Types of Reviews

Reproduced from: Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009;26(2):91‐108. doi:10.1111/j.1471-1842.2009.00848.x
PMID: 19490148

Label Description Search Appraisal Synthesis Analysis
Critical Review Aims to demonstrate writer has extensively researched literature and critically evaluated its quality. Goes beyond mere description to include degree of analysis and conceptual innovation. Typically results in hypothesis or model. Seeks to identify significant items in the field. No formal quality assessment. Attempts to evaluate according to contribution. Typically narrative, perhaps conceptual or chronological. Significant component: seeks to identify conceptual contribution to embody existing or derive new theory.
Mapping Review/Systematic Map Map out and categorize existing literature from which to commission further reviews and/or primary research by identifying gaps in research literature Completeness of searching determined by time/scope constraints No formal quality assessment May be graphical and tabular Characterizes quantity and quality of literature, perhaps by study design and other key features. May identify need for primary or secondary research
Mixed Studies Review/Mixed Methods Review Refers to any combination of methods where one significant component is a literature review (usually systematic). Within a review context it refers to a combination of review approaches for example combining quantitative with qualitative research or outcome with process studies Requires either very sensitive search to retrieve all studies or separately conceived quantitative and qualitative strategies Requires either a generic appraisal instrument or separate appraisal processes with corresponding checklists Typically both components will be presented as narrative and in tables. May also employ graphical means of integrating quantitative and qualitative studies Analysis may characterise both literatures and look for correlations between characteristics or use gap analysis to identify aspects absent in one literature but missing in the other
Overview Generic term: summary of the [medical] literature that attempts to survey the literature and describe its characteristics May or may not include comprehensive searching (depends on whether systematic overview or not) May or may not include quality assessment (depends whether systematic overview or not) Synthesis depends on whether systematic or not. Typically narrative but may include tabular features Analysis may be chronological, conceptual, thematic, etc.
Qualitative Systematic Review/Qualitative Evidence Synthesis Method for integrating or comparing the findings from qualitative studies. It looks for ‘themes’ or ‘constructs’ that lie in or across individual qualitative studies May employ selective or purposive sampling Quality assessment typically used to mediate messages not for inclusion/exclusion Qualitative, narrative synthesis Thematic analysis, may include conceptual models
State-of-the-Art Review Tend to address more current matters in contrast to other combined retrospective and current approaches. May offer new perspectives on issue or point out area for further research Aims for comprehensive searching of current literature No formal quality assessment Typically narrative, may have tabular accompaniment Current state of knowledge and priorities for future investigation and research
Systematic Search and Review Combines strengths of critical review with a comprehensive search process. Typically addresses broad questions to produce ‘best evidence synthesis’ Aims for exhaustive, comprehensive searching May or may not include quality assessment Minimal narrative, tabular summary of studies What is known; recommendations for practice. Limitations