Workflow | Carol Hollier| May 18, 2020
Carol Hollier, a librarian and information literacy expert at IFIS Publishing, distinguishes between a systematic review and a systematic literature review.
For those not immersed in systematic reviews, understanding the difference between a systematic review and a systematic literature review can be confusing. It helps to realise that a “systematic review” is a clearly defined thing, but ambiguity creeps in around the phrase “systematic literature review” because people can and do use it in a variety of ways.
A systematic review is a research study of research studies. To qualify as a systematic review, a review needs to adhere to standards of transparency and reproducibility. It will use explicit methods to identify, select, appraise, and synthesise empirical results from different but similar studies. The study will be done in stages:
Some reviews also state what degree of confidence can be placed on that answer, using the GRADE scale. By going through these steps, a systematic review provides a broad evidence base on which to make decisions about medical interventions, regulatory policy, safety, or whatever question is analysed. By documenting each step explicitly, the review is not only reproducible, but can be updated as more evidence on the question is generated.
Sometimes when people talk about a “systematic literature review”, they are using the phrase interchangeably with “systematic review”. However, people can also use the phrase systematic literature review to refer to a literature review that is done in a fairly systematic way, but without the full rigor of a systematic review.
For instance, for a systematic review, reviewers would strive to locate relevant unpublished studies in grey literature and possibly by contacting researchers directly. Doing this is important for combatting publication bias, which is the tendency for studies with positive results to be published at a higher rate than studies with null results. It is easy to understand how this well-documented tendency can skew a review’s findings, but someone conducting a systematic literature review in the loose sense of the phrase might, for lack of resource or capacity, forgo that step.
Another difference might be in who is doing the research for the review. A systematic review is generally conducted by a team including an information professional for searches and a statistician for meta-analysis, along with subject experts. Team members independently evaluate the studies being considered for inclusion in the review and compare results, adjudicating any differences of opinion. In contrast, a systematic literature review might be conducted by one person.
Overall, while a systematic review must comply with set standards, you would expect any review called a systematic literature review to strive to be quite comprehensive. A systematic literature review would contrast with what is sometimes called a narrative or journalistic literature review, where the reviewer’s search strategy is not made explicit, and evidence may be cherry-picked to support an argument.
A systematic review is a research study of research studies. To qualify as a systematic review, a review needs to adhere to standards of transparency and reproducibility.
A defining characteristic of a systematic literature review is its thoroughness. A systematic review must capture all the relevant literature on a question so that its conclusion is based on all available evidence. Because FSTA indexes research articles related to the science of food and health wherever they appear, including journals not indexed in PubMed, Web of Science, CAB Abstracts, or other databases, using FSTA will help ensure that literature searches are exhaustive.
FSTA allows you to easily search for review articles (both narrative and systematic reviews) by using the subject heading or thesaurus term “REVIEWS" and an appropriate free-text keyword.
In 2011 FSTA introduced the descriptor META-ANALYSIS, making it easy to search specifically for systematic reviews that include a meta-analysis published from that year onwards.
Systematic reviews with meta-analyses published before 2011 are included in the REVIEWS controlled vocabulary term in the thesaurus.
An easy way to locate pre-2011 systematic reviews with meta-analyses is to search the subject heading or thesaurus term "REVIEWS" AND meta-analysis as a free-text keyword AND another appropriate free-text keyword.
EBSCO offers FSTA – Food Science and Technology Abstracts on EBSCOhost® and EBSCO Discovery Service™. EBSCO, along with IFIS, recently sponsored the Research Information webinar, “Literature reviews in food science – what, why and how?”
*This post was originally published by IFIS Publishing on the Thought for Food Blog.
Before joining IFIS, Carol worked in academic libraries in student and faculty facing roles that involved teaching research and information literacy skills. She has been a Reference and Instruction Librarian at The Ohio State University, an Academic Subject Librarian at the University of Lincoln (UK), and Faculty Team Librarian supporting the School of Biosciences at the University of Nottingham. Her most recent role before moving to IFIS was Senior Librarian, Teaching and Learning Support at the University of Nottingham. Carol holds a Master’s in Library and Information Science from Kent State University, a Postgraduate Certificate in Teaching and Learning in Higher Education from the University of Lincoln and is a Fellow of the Higher Education Academy.
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