A selection of the common review types found in the literature is presented and compared in the following table using the SALSA framework developed by Grant and Booth (2009).
| Name | 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 mode |
Seeks to identify most significant items in the field |
No formal quality assessment. Attempts to evaluate according to contribution |
No formal quality assessment. Attempts to evaluate according to contribution |
Significant component: seeks to identify conceptual contribution to embody existing or derive new theory |
| Literature review |
Generic term: published materials that provide examination of recent or current literature. Can cover wide range of subjects at various levels of completeness and comprehensiveness. May include research findings
|
May or may not include comprehensive searching |
May or may not include quality assessment
|
Typically narrative | Analysis may be chronological, conceptual, thematic, etc. |
| 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 |
| Meta-analysis | Technique that statistically combines the results of quantitative studies to provide a more precise effect of the results. Often used within a systematic review | Aims for exhaustive, comprehensive searching. May use funnel plot to assess completeness | Quality assessment may determine inclusion/ exclusion and/or sensitivity analyses | Graphical and tabular with narrative commentary | Numerical analysis of measures of effect assuming absence of heterogeneity |
| Mixed Methods Review | 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 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 Review | 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 |
| Rapid review | Assessment of what is already known about a policy or practice issue, by using systematic review methods to search and critically appraise existing research | Completeness of searching variable, determined by time constraints | Time-limited formal quality assessment | Typically narrative and tabular | Quantities of literature and overall quality/direction of effect of literature |
| Scoping review | Preliminary assessment of potential size and scope of available research literature. Aims to identify nature and extent of research evidence (usually including ongoing research) | Completeness of searching determined by time/scope constraints. May include research in progress | No formal quality assessment | Typically tabular with some narrative commentary | Characterizes quantity and quality of literature, perhaps by study design and other key features. Attempts to specify a viable review |
Adapted from:
Grant, M.J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26: 91-108. https://doi.org/10.1111/j.1471-1842.2009.00848.x