"Comprehensive reviews" is an umbrella term. It refers to any review where the literature search is exhaustive and documented in a detailed and thorough way in accordance with accepted standards to avoid outcome bias. Conversely, a non-comprehensive review (typically a narrative review) is not beholden to the same standards, rigor or time commitment.
A systematic review is one type of comprehensive review. It is a review of a "clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review" (PRISMA Statement). Statistical techniques (meta-analysis) may optionally be used to analyze the results of included studies of a systematic review. For biostatistics consultations, contact the MGH Division of Clinical Research or the Harvard Catalyst Biostatistics Consultation Service.
Comprehensive reviews are also protocol-driven. Similar to how one would not embark on primary research without a protocol, one should have a protocol in place before initiating a systematic review.
The table below breaks down which review types are considered comprehensive and which are not:
|Comprehensive Reviews||Non Comprehensive Reviews|
|Systematic Reviews||Narrative Reviews|
|Scoping Reviews||Critical Reviews|
It's important to have a good understanding of whichever review type you would like to pursue. Below are articles that talk more in depth about the differences between reviews. You can also use the "Which Review Is Right For You?" tool to help guide you in choosing a methodology.
Grant MJ, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies. Health Info Libr J. 2009 Jun;26(2):91-108. https://onlinelibrary.wiley.com/doi/10.1111/j.1471-1842.2009.00848.x
Munn Z, Stern C, Aromataris E, Lockwood C, Jordan Z. What kind of systematic review should I conduct? A proposed typology and guidance for systematic reviewers in the medical and health sciences. BMC Med Res Methodol. 2018 Jan 10;18(1):5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5761190
Sutton A, Clowes M, Preston L, Booth A. Meeting the review family: exploring review types and associated information retrieval requirements. Health Info Libr J. 2019 Sep;36(3):202-222. https://onlinelibrary.wiley.com/doi/10.1111/hir.12276
Petticrew M. Systematic reviews from astronomy to zoology: myths and misconceptions. BMJ. 2001 Jan 13;322(7278):98-101. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1119390/
Treadwell offers two tiers of review service, adapted from Harvard's model:
Level I: Acknowledgement
Level II: Co-authorship
|Initial consultation meeting||
All level I services
Develop a Medline search strategy using controlled vocabulary and keywords
Offer advice on feasibility and construction of research question and methodology best practices
|Identification and suggestion of other databases for extending search||Edit sections of the protocol that document the search|
Advice on citation and project management tools
|Translate Medline search strategy into other databases using controlled vocabularies and keyword selections|
|Create PRISMA-compliant search documentation|
|Deliver citation results using a Covidence project after removing duplicates|
Author literature search methodology for the final manuscript
|Review manuscript before submission and draft responses to peer reviewers or editors if questions arise regarding the search|
NOTE: Due to overwhelming demand and not enough current staffing to handle it, we have been forced to temporarily suspend our comprehensive review service.
Unfortunately, our wait list has reached the point where we feel it's unrealistic to continue adding projects to the list. We suggest trying to leverage a librarian at a different institution if someone on your team has another affiliation, or hiring a contract librarian if you have the funds available. Additionally, below are some suggested resources outside of MGH that could help:
Tutorials and classes to learn how to perform the literature search:
How to find a independent contract worker to perform the literature search:
Independent consultancies exist such as Systematic Review Consultants LTD, Effective Evidence and others. You can also post a call for work to the following listervs: expert searching (requires Medical Library Association membership) or MEDLIB-L (no membership required).
We'll be working hard to have the ability to ramp back up our service in the meantime. If no other options are available to you, you can try us again in August to see where we stand with continuing the service at that time. If you have questions, please direct them to firstname.lastname@example.org.
Contact us if:
To begin the process, submit a request by filling out this intake form. Once your form has been reviewed, you'll receive an email arranging a time for a virtual consultation.
Learn how to conduct systematic reviews in our Systematic Review Process and Systematic Review Standards pages.
Resources about other common comprehensive review methodologies are listed below.
Scoping reviews serve to synthesize evidence and assess the scope of literature on a topic. Among other objectives, scoping reviews help determine whether a systematic review of the literature is warranted.
Systematic reviews of systematic reviews
Rapid reviews omit parts of the systematic review process to speed up the review process.
Integrative reviews are most often seen in the nursing discipline.
Living Systematic Reviews
Living systematic reviews are continually updated reviews that may be used to synthesize rapidly evolving areas of research.
Treadwell provides access to Covidence, an online platform that aims to accelerate the systematic review process, at no cost to MGH employees. MGH employees can also invite individuals from outside of MGH to collaborate on systematic reviews at no cost.
Covidence is accessible by computer or mobile device, and provides one convenient place to screen citations, assess risk of bias, and extract data.
To access Covidence, request an invitation here using your mgh.harvard.edu or mghihp.edu e-mail address. Do not use your partners.org or mgb.org address.
Have a MGH Covidence account already? Log in here.
Learn How to Get Started With Covidence
For videos and written instructions to help you get started with Covidence, see our support page in the Covidence Knowledge Base.