Advanced Reviews are part of the Evidence Synthesis umbrella. Evidence Synthesis is a group of research methodologies, primarily focused on the analysis of secondary data and marked by the principles of transparency, reproducibility, and reduction of bias. At its most basic level, evidence synthesis is just what it sounds like, a synthesis of the existing evidence on a topic. Many different research methodologies fall under this umbrella, including a cluster we are referring to as Advanced Reviews.
In the literature and across disciplines, 'evidence synthesis' and 'systematic review' are often used interchangeably. Please refer to the Systematic Reviews tab for more precise definitions of these reviews.
We use the terminology of ‘advanced reviews’ to refer to methodologies that include multiple systematic methods for secondary analysis, focusing on the systematic nature specifically of the search process, aka data collection. This reflects the evolution from integrations (Feldman, 1971) to meta-analyses (Glass, 1976), integrative reviews (Cooper, 1982), and finally systematic reviews (Cochrane, 1989).
In sum, advanced reviews are evidence synthesis methodologies based around a comprehensive literature review.
Advanced reviews fall within a broader category of evidence synthesis. Evidence synthesis includes advanced review frameworks, like systematic reviews, scoping reviews, and qualitative evidence syntheses, and individual synthesis methods that can be used within these frameworks, like meta-analyses, content analyses, meta-aggregations, meta-syntheses, meta-narratives, concept analyses, thematic syntheses, and meta-ethnographies.
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Learn more about the different types of reviews:
Evidence Synthesis is:
(from “What Is Evidence Synthesis?” Evidence Synthesis International, 25 August 2023, evidencesynthesis.org/what-is-evidence-synthesis/.
Evidence syntheses are much more time-intensive than traditional literature reviews and require a multi-person research team. See this PredicTER tool to get a sense of a systematic review timeline (one type of evidence synthesis). Before embarking on an evidence synthesis, it's important to clearly identify your reasons for conducting one.
This decision tree by Cornell University Libraries will assist you in determining what kind of review is right for your project:
What Type of Review is Right for you?
For more information about different types of advanced review projects, see:
A typology of reviews: An analysis of 14 review types and associated methodologies
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.libproxy.unl.edu/10.1111/j.1471-1842.2009.00848.x
This table is a further aid in comparing the aims of a traditional literature review with a systematic review.
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Traditional Literature Review |
Systematic Review |
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Review Question/Topic |
Topics may be broad in scope; the goal of the review may be to place one's own research within the existing body of knowledge, or to gather information that supports a particular viewpoint. |
Starts with a well-defined research question to be answered by the review. Reviews are conducted with the aim of finding all existing evidence in an unbiased, transparent, and reproducible way. |
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Searching for Studies |
Searches may be ad hoc and based on what the author is already familiar with. Searches are not exhaustive or fully comprehensive. |
Attempts are made to find all existing published and unpublished literature on the research question. The process is well-documented and reported. |
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Study Selection |
Often lack clear reasons for why studies were included or excluded from the review. |
Reasons for including or excluding studies are explicit and informed by the research question. |
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Assessing the Quality of Included Studies |
Often do not consider study quality or potential biases in study design. |
Systematically assesses risk of bias of individual studies and overall quality of the evidence, including sources of heterogeneity between study results. |
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Synthesis of Existing Research |
Conclusions are more qualitative and may not be based on study quality. |
Bases conclusion on quality of the studies and provide recommendations for practice or to address knowledge gaps. |