Classic
Syntheses Synthesized: A Look Back at
Grant and Booth's Review Typology
A Review of:
Grant, M. J., & Booth, A. (2009). A
typology of reviews: An analysis of 14 review types and associated
methodologies. Health Information and
Libraries Journal, 26(2), 91–108.
https://doi.org/10.1111/j.1471-1842.2009.00848.x
Reviewed by:
Carrie Price
Health Professions Librarian
Albert S. Cook Library
Towson University
Towson, Maryland, United
States of America
Email: carrieprice@towson.edu
Received: 11 Jan. 2022 Accepted: 22 Mar. 2022
2022 Price. This is an Open Access
article distributed under the terms of the Creative Commons‐Attribution‐Noncommercial‐Share Alike License 4.0 International
(http://creativecommons.org/licenses/by-nc-sa/4.0/),
which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly attributed, not used for commercial
purposes, and, if transformed, the resulting work is redistributed under the
same or similar license to this one.
DOI: 10.18438/eblip30093
Abstract
Objective – The article, published in 2009, aims to provide a
descriptive analysis of common review types to dispel confusion and misapplication
of terminology.
Design – An examination of terminology and methods applied in
published literature reviews.
Methods – Grant and Booth preliminarily performed a scoping
search and drew on their own experiences in health and health information
theory and practice. Using literature reviews from the Health Information and Libraries Journal review feature and reviews
identified in a previously published evaluation of methods in systematic
reviews and meta-analyses (Ankem, 2008), Grant and
Booth examined characteristics of literature reviews. They subsequently
identified variations in literature review methodologies and correlating
vocabulary. After arriving at the conclusion that probing the review titles and
descriptions—or alternatively, examining review workflow and timeframe
processes—were not accurate for classifying review types, the authors chose to
apply an analytical framework called Search, AppraisaL,
Synthesis, and Analysis (SALSA). By examining the scope of the search, the
method of appraisal, and the nature and characteristics of the synthesis and
analysis, SALSA helped the authors describe and characterize the "review
processes as embodied in the description of the methodology" (Grant &
Booth, 2009, p. 104). By employing an objective technique to categorize
literature review types, the authors generated a descriptive typology.
Main Results – The authors provided a descriptive typology for 14
different literature reviews: critical review, literature review, mapping
review/systematic map, meta-analysis, mixed studies review/mixed methods
review, overview review, qualitative systematic review/qualitative evidence
synthesis, rapid review, scoping review, state-of-the-art review, systematic
review, systematic search and review, systematized review, and umbrella review.
With the application of the SALSA framework, the literature review types were
defined and narratively described and summarized, along with perceived
strengths, weaknesses, and a previously published example provided for
comparison. Two tables supplied a quick reference for comparing literature
review types and examining selected reviews. A breakdown of review types was
followed by a discussion of using and developing reviews in the library and
health information science domain.
Conclusion – Inconsistency in nomenclature and methods across
literature reviews perpetuates significant confusion among those involved in
authoring or deciphering literature reviews. Grant and Booth noted the lack of
an internationally agreed-upon set of review types, the formulation of which
would set a precedent for a better understanding of what is expected and
required of such publications. In supplying a historical context of the
literature review (detailing both its importance as a synthesis of primary
research and its value to users), Grant and Booth provided a useful narrative
and typology to "inform how LIS workers might approach the appraisal or
development of a health information review" (p. 106).
Commentary
Background of the Work
The publication of literature reviews, systematic and
otherwise, has been on the rise for decades, at the very least since
epidemiologist Archie Cochrane famously criticized the lack of a formal summary
of research evidence in medicine (Cochrane, 1979). Evidence-inclined educators,
researchers, practitioners, and students in various domains place value in
reviews of the literature and consequently seek them out to inform research,
policy, and practice. Readers of reviews have found that methodological quality
cannot be assumed and that reviews may follow disparate methods, introduce
bias, or lack quality assessment or appropriate synthesis (Shea et al., 2002;
Shea et al., 2007) despite stated methods.
Prior to 2009, publications had evaluated and
described singular literature review methodologies, such as systematic and
scoping reviews. One famous example is the Cochrane Handbook for Systematic
Reviews of Interventions, the first version of which was developed and
published in 1994 (Cochrane, 2021) with successive versions to come. Yet
another example of an in-depth description of methodology is the still-relevant
scoping studies' methodological framework articulated by Arksey & O'Malley
in 2005.
Likewise, other publications focused on the art and
conduct of general literature reviews. Perhaps most notable is a publication
that appeared in 1988. Oxman and Guyatt
in "Guidelines for Reading Literature Reviews" created a guide for
readers of literature reviews who were grappling with increasing, and
increasingly overwhelming, amounts of published medical literature. In their
parting sentiments, Oxman and Guyatt
(1988) state that "just as flawed methods in a study of diagnosis or
therapy may invalidate the results, an unscientific literature review may come
to incorrect conclusions" (p. 697). The 1988 publication facilitated
future work, such as a literature review checklist (Oxman,
1994), an article series (Oxman et al., 1993) on
reading the medical literature, and the User's Guide to the Medical
Literature, now in its third edition (Guyatt et
al., 2001). In 1997, Greenhalgh included a chapter on "papers that
summarize other papers" in her extensive How to Read a Paper: The
Basics of Evidence-Based Medicine, focusing primarily on systematic reviews
of the literature.
A few publications began to compare evidence synthesis
methods but with limited attention or momentum. In 1988, Cooper devised a
taxonomy of literature reviews in education and psychology. There was
difficulty in separating "what one hears from what one hopes to hear, and
what is from what ought to be" (p. 123), leading again to the conclusion
that "efforts at systematic evaluation will be fruitless unless a
descriptive scheme . . . exists to structure the discussion" (p. 125).
Finally, it was just before Grant and Booth's typology
publication that literature review assessment tools started to appear such as
the Assessment of Multiple Systematic Reviews (AMSTAR) Checklist and the
subsequent AMSTAR-2. Tools such as these aimed to help readers assess
methodological quality in systematic reviews (Shea et al., 2007; Shea et al.,
2017).
Prior to Grant and Booth (2009), no other authors had
so clearly categorized and described 14 common literature review types. Grant
and Booth, both fully aware of evolving trends in evidence-based medicine,
describe the use of the systematic literature review to synthesize research
evidence in health care: "Gathering research, getting rid of rubbish and
summarizing the best of what remains captures the essence of the science of
systematic review" (p. 92).
The application of explicit methods to literature
reviews is, Booth anticipated as early as 2001, a practice that should be
adopted in the library and information science sector for the purpose of
"establishing a solid evidence base" within a field that had little
(Grant & Booth, 2009, p. 92). "Given the importance evidence-based
practice places upon the retrieval of appropriate information," ambiguous
and inconsistent terminology only perpetuates further uncertainty (Grant &
Booth, 2009, p. 93).
In a 2017 letter in the Health Information and
Libraries Journal, Grant reflects on one of the typology's catalysts. As a
new review editor at the journal in 2007, Grant realized that "there were
no consistent guidelines on the features a review should incorporate
perpetuating a sense of confusion about what . . . was an indistinct and
misapplied term" (p. 1). Grant goes on to note that it was the shortage of
consistent guidelines that led her to coauthor with Booth.
Expanding on Ankem's (2008)
work, which evaluated systematic review and meta-analysis methods in LIS
journals, Grant and Booth provided an "explicit basis . . . to gain a
clear understanding of what [method] is being requested and the resources . . .
required to meet the specification" for various types of literature
reviews (Grant & Booth, 2009, p. 104).
Impact of the Work
Grant and Booth's work ignited a spark for those, both
inside and outside of health information science, who hoped to see an
implementation of more appropriate, more transparent, and more consistent
methods for knowledge and evidence synthesis publications. While Grant and
Booth originally set out to describe literature reviews in health information
topics, the resulting publication proved useful for its generalizability to
other fields and disciplines. It is likely for this reason that the article has
been so popular in higher education, becoming highly cited not only in library
science and health methods research but in other domains such as social and
environmental science, psychology, business, engineering, computer science, and
even the arts and humanities (Scopus, n.d.). The article has had over 3,100
citations as of March 2022, with over 900 citations just in 2021 alone (Scopus,
n.d.). Google Scholar reports almost twice as many cumulative citations as
Scopus (Google Scholar, n.d.). The article's Altmetric
Attention Score, which is representative of online attention and other
nontraditional metrics, was 394 as of March 2022 (Altmetric,
n.d.; Elmore, 2008). A score of 20 or more, according to Altmetric,
demonstrates a higher-than-average level of attention (Altmetric
Support, 2020). The article's significant Altmetric
Attention Score indicates that through media attention, including Tweets, blog
posts, and more, it has been shared widely on various digital platforms.
Another indicator of this article's impact is the
frequency with which it appears on library websites. A web search locates this
article on many academic library literature review sites and guides, with over
100,000 Google results in a search for this article's title limited to the .edu domain. These types of guides are frequently
disseminated to educators or researchers by library staff when approached
seeking guidance about literature reviews. In consulting the typology,
potential authors can simplify the task of selecting the appropriate literature
review methodology for their research and choose the one that aligns with their
goals and objectives. Readers of the
typology will also note the early discussion of the utility and purpose of
"systematized" reviews, instructed to be "typically conducted as
a postgraduate student assignment, in recognition that they are not able to
draw upon the resources required for a full systematic review" (Grant
& Booth, 2009, p.102).
Since 2009, both authors have contributed further to
the topics of methods, searching, writing, and reporting with Grant's focus on
public health writing and Booth's attention on qualitative evidence synthesis
and methods. In 2019, Booth collaborated once again, this time with different
coauthors, on a publication that identified 48 review types and categorized
them into seven broad review families (Sutton et al., 2019). Despite the
thoroughness and expansion on methodological approaches of this more recent
article and others that followed, the simplicity of the 2009 typology can be
more easily understood and therefore more easily applied by those starting out
in evidence synthesis.
Implications of the Work
The Grant and Booth typology helps authors contribute
to the evidence base and transform the knowledge landscape in their own
disparate fields in consistent ways (Grant & Booth, 2009). The work
encourages transparency in applied methods and sets out best practices, such as
defining the scope of the search, describing the need and nature of quality
assessment, and identifying the appropriate types of synthesis and analysis.
All of these topics are receiving significant attention in academic communities
today.
The typology has made its way into instructions for
authors: any potential authors wishing to submit a review article to Health Information and Libraries Journal
will find a link to the Grant and Booth article on the "Author
Guidelines" page (Health Information
and Libraries Journal, 2022), setting a worthy example for other journals
and placing a responsibility on editors to adhere to published standards and
consistency.
Furthermore, review authors are beginning to
understand the value of collaborating with a librarian or information
specialist. Various research demonstrates that librarians can contribute to
more thorough search methods reporting (Meert et al.,
2016), higher quality searches (Rethlefsen et al., 2015), and other unique
skills such as records management, methods education (Dudden
& Protzko, 2010), and publishing. Professional
expert review guidance like the Institute of Medicine's Finding What Works
in Healthcare: Standards for Systematic Reviews (Institute of Medicine,
2011), the Cochrane Handbook for Systematic Reviews of Interventions
(Higgins et al., 2022), and the JBI Manual for Evidence Synthesis (Aromataris et al., 2020) all encourage authors to
collaborate with a librarian or information specialist for search strategy
development in reviews of the evidence. Along with this evolving trend comes
the need for established best practices and guidance. Over the past decade, a
corpus of literature has started to emerge for those who would take on roles in
literature review teams and participate in educating potential authors about
appropriate review methodologies. Many of these publications reference or build
upon Grant and Booth's classic article. For example, the JBI Manual for
Evidence Synthesis (Aromataris et al., 2020)
explores methodological approaches for systematic reviews that are both
interventional and non-interventional in nature while also advancing the
methodology of scoping reviews that was first thoroughly examined by Arksey and
O'Malley (2005) and later listed among Grant and Booth's (2009) 14 review
types. Another notable development in the literature since the publication of
Grant and Booth's typology article is the standardization of reporting for
systematic and scoping reviews through the PRISMA Statement and its extensions
for protocols, searching, scoping reviews, and more (Page et al., 2020).
Grant and Booth succeeded in establishing a
well-regarded typology that has stood the test of time and is still being
frequently consulted and cited over a decade later. The 14 identified review
types, which align with prospective objectives and research designs, is
referenced by subsequent detailed guidance. Developing terminological and
methodological consistency will allow the "distinguishing features of each
review type [to] be built up within the systematic review community through
both direct comparison and emerging precedent" (Grant & Booth, 2009,
p. 104). Certainly, Grant and Booth's contributions benefit the global evidence
synthesis community. The article's simplicity and straightforward approach make
it an ideal starting point for many. Through their typology, Grant and Booth
have empowered those involved in evidence and knowledge synthesis to make
appropriate decisions for the conduct and methodological applications of
literature reviews not only in health information science but also in numerous
other fields.
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