- •Living systematic review was proposed in 2014 as an approach to systematic review updating. Since that time, many issues associated with the production and publication of living systematic reviews have been explored and are now being tested in a series of living systematic review projects (Cochrane and non-Cochrane).
- •This series presents the current state of development of living systematic reviews by members of the international Living Systematic Review Network.
- •This paper gives an overview of recent living systematic review developments in production and publication, including a working definition of living systematic review, when living systematic reviews are appropriate, and current approaches to living systematic review production.
1. Keeping evidence up to date
2. Continual updating
- •A systematic review that is continually updated, incorporating relevant new evidence as it becomes available
- •An approach to review updating, not a formal review methodology
- •Can be applied to any type of review
- •Uses standard systematic review methods
- •Explicit and a priori commitment to a predetermined frequency of search and review updating
- Living systematic reviews: 1. Introduction—the why, what, when, and how
- Authors: Julian Elliott, Annie Synnot, Tari Turner, Mark Simmonds, Eli Akl, Steve McDonald, Georgia Salanti, Joerg Meerpohl, Harriet MacLehose, John Hilton, David Tovey, Ian Shemilt, James Thomas on behalf of the Living Systematic Review Network
- Description: Julian Elliott et al. provide an introduction and overview of the why, what, when, and how of living systematic reviews. Key issues in living systematic review are discussed, including search, updating scenarios, production processes, editorial and peer review, and publication and links to downstream activities, including living recommendations.
- Living systematic reviews: 2. Combining human and machine effort
- Authors: James Thomas, Anna Noel-Storr, Byron Wallace, Steven McDonald, Chris Mavergames, Paul Glasziou, Iain Marshall, Ian Shemilt, Annie Synnot, Tari Turner, Julian Elliott on behalf of the Living Systematic Review Network
- Description: James Thomas et al. outline how new technologies which utilize human and machine effort, such as text mining, machine learning, and crowd sourcing, can enable significant production efficiencies, increasing the feasibility of continual updating. They discuss the potential and limitations of these systems, where they are in use, and where further research is needed.
- Living systematic reviews: 3. Statistical methods for updating meta-analyses
- Authors: Mark Simmonds, Georgia Salanti, Phillipe Ravaud, Julian Higgins, Jo McKenzie, Julian Elliott on behalf of the Living Systematic Review Network
- Description: Living systematic reviews often require repeated meta-analyses, which may increase the risk of spurious statistical significance. Mark Simmonds et al. discuss important issues relevant to meta-analyses and network meta-analyses within living systematic reviews. Various methods that have been proposed to address these issues are reviewed and described.
- Living systematic reviews: 4. Living guideline recommendations
- Authors: Elie Akl, Joerg Meerpohl, Julian Elliott, Lara Kahale, Holger Schunemann on behalf of the Living Systematic Review Network
- Description: “Living guidelines” hold the promise of providing timely, up-to-date and high-quality guidance to target users. Elie Akl et al. describe key issues in living guidelines, including when living guidelines are appropriate, workflows, linkages with living systematic reviews, thresholds for changing recommendations, and approaches to publication and dissemination.
3. What is a living systematic review?
4. When is an LSR appropriate?
- 1.The systematic review is a priority for decision-making. With current review production and publication systems, LSRs are only appropriate when the question is of sufficient importance to decision-making that the allocation of ongoing resources is worthwhile. Over time, we expect the scope of questions in which an LSR approach is appropriate to expand.
- 2.Certainty in the existing evidence is low or very low. An LSR will be useful when the current body of evidence does not provide certainty, and new information is likely to change the findings of the systematic review.
- 3.There is likely to be new research evidence. LSRs are most appropriate when the research field covered by the systematic review is moving relatively quickly, and new evidence is emerging.
5. How to perform an LSR?
5.1 Protocol development
- •A clear justification for the review being maintained as a living systematic review.
- •An explicit statement that the review will be maintained as a living systematic review.
- •A description of the frequency of searching for all sources.
- •A description of the frequency of screening, ideally matched to the frequency of searching.
- Data synthesis
- •A statement describing whether new evidence will be immediately incorporated into the review or may be deferred under certain circumstances.
- •If the incorporation of new evidence may be deferred, a description of the decision framework that will be applied to inform this decision.
- •A description of the planned statistical approach to updating of any meta-analyses.
- •A description of any systematic review enablers (such as machine learning or citizen science) used in the review.
- •A statement of the frequency with which the team will regularly review the review scope and methods, including search methods and strategies.
- •Specific thresholds for transitioning out of a Living systematic review mode, if known.
5.2 Producing an up-to-date systematic review
5.3 Transition to an LSR
5.5 Update scenarios
5.6 Production process
5.7 Enabling technologies
5.8 Updating of meta-analyses
5.9 Editorial and peer review
5.11 Links to other “living” activities
- •Keep the end user in mind, maximizing the utility of the review at all stages
- •Minimize additional workload for authors, peer reviewers, editors, and publishers
- •Maximize visibility of the latest findings for the reader
- •Maximize efficiencies through technology and the crowd
- •Streamline workflows and editorial processes
- •Do not reinvent the wheel but build on existing processes and platforms
- •Focus on workable, not perfect, solutions
- •Remain flexible to incorporate new developments in the broader evidence ecosystem
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Funding: The Living Systematic Review Network is supported by funding from Cochrane and the Australian National Health and Medical Research Council (Partnership Project grant APP1114605).