Systematic Reviews
A systematic review (SR) seeks to answer a specific research question by analyzing and synthesizing a broad range of published evidence. They provide reliable findings that can inform research, practice, policy, and decision-making.
Is a SR Right For You?
A SR differs from other types of literature reviews in its use of a comprehensive, pre-defined research process. This is typically documented in a protocol to guide the search, selection, appraisal, and analysis of studies. This methodology is time-intensive, but designed to minimize bias, ensuring transparency, and reproducibility.
By contrast, a systematized review often follows the same initial protocol-guided steps but falls short of the rigorous reproducibility standards of a systematic review. For projects that are not intended for publication or formal conference presentation, a systematized review may provide a practical alternative to a full systematic review. Use the What Type of Review is Right for You decision tree and the Right Review website to decide which review is right for you.
Process Overview and Tools
The systematic review process consists of distinct steps.
Research Question
Formulate a precise research question that fills an information gap. It can be helpful to examine a few published studies on your topic to better understand the existing research and identify areas for further investigation. Using a framework such as PICO can help you clearly define and structure your research question.
Protocols & PRISMA
A protocol is a written plan created before conducting your search. It prevents retrospective adjustment to the search that could introduce bias. It describes the research objectives, search strategy, and defines your inclusion/exclusion criteria for selecting articles to include in your review, screening procedure, and synthesis strategy. It is recommended that you register your protocol so that it is made publicly available ahead of seeking publication.
PRISMA is a research guideline standard that includes a 27-item checklist. It is organized into seven sections covering title, abstract, introduction, methods, results, discussion, and an extension for reporting a literature search strategy. This maps to the number of record identified, excluded, and included at each stage of a systematic review.
Register Your Protocol
The most common protocol combination is: PROSPERO + PRISMA. For a systematized review, PROSPERO may not be appropriate, but the Open Science Framework (OSF) can still be used to document and share the protocol. For other review types, consider the JBI Manual for guidance.
- PRISMA
- Guideline for reporting systematic reviews, with checklists, and other resources.
- PROSPERO
- An internationally-recognized protocol registry.
- Open Science Framework (OSF) Registries
- An open-access online workspace where you can store and share your protocol, data, search strategies, and other project materials.
- Joanna Briggs Institute (JBI) Manual for Evidence Synthesis
- Provides standardized methodologies for conducting and reporting evidence syntheses, including systematic reviews, scoping reviews, and other review types.
Literature Search
Your literature search starts by determining appropriate terms and identifying which databases may be more useful for your research topic. These steps should be well documented for research reproducibility and transparency, including dates of search and filters applied. Contact your subject librarian for literature search assistance or search strategy recommendations specific to your topic.
Learn more about the research process and consider these literature search tools as you expand your search to meet SR criteria
Literature Search Tools
- LitSense
- Returns relevant sentences from the biomedical literature that best match the query sentence provided by the user. Filter search results by Article Section or Publication Year.
- ISSG Search Filters Resource
- Find pre-built search filters by specific study design or focus.
- McMasters Health Knowledge Refinery Hedges Project
- Search strategies, or Hedges, specifically designed to assist searches in PsychInfo, Medline and Embase.
- Yale MeSH Analyzer
- Enter PubMed article IDs (PMID) to identify common MeSH terms, keywords, and indexing patterns that can be incorporated into a search hedge.
- Polyglot Search Translator
- Once you have a well-built search block, copy it into the polyglot query box to translate the block to other database vocabularies and formats.
- The Evidence Review Accelerator (TERA)
- A suite of systematic review tools including search refinement, term identification, and strategy development utilities. Create and run one SR project free.
Screening
Screening is the process of reviewing search results to determine which studies meet the review’s predefined inclusion and exclusion criteria. Screening typically occurs in stages, beginning with titles and abstracts and followed by full-text review.
Screening Tools
- Rayyan
- Rapid title/abstract screening with AI-assisted ranking, keyword highlighting, easy reviewer collaboration, and up to three active reviews on the free plan.
- Abstrackr
- A free screening platform that includes automatic conflict detection, a live PRISMA numbers table, and a ranking queue that learns your inclusion criteria.
- Covidence
- Offers easy end-to-end review workflow that streamlines screening, full-text review, data extraction, and risk-of-bias assessment. Requires a subscription.
- DistillerSR
- Subscription tool that provides advanced customization and automation for complex reviews.
Appraisal
Critical appraisal, or quality assessment, is the process of evaluating the methodological quality, validity, and risk of bias of your screened results. Appraisal helps reviewers assess the strength and trustworthiness of the evidence and informs interpretation of review findings.
Appraisal Tools
- Quality of Evidence Checklist
- Our guide which defines and describes approaches to critical appraisal, offering further tools and resources.
- JBI Critical Appraisal Tools
- Downloadable checklists to assess the quality of research for many study types.
- Catalog of Bias
- Evidence-based descriptions that outline potential impact and preventative steps for several known biases.
Analysis & Synthesis
This is the process of organizing and analyzing data from included studies to identify patterns, relationships, or differences. If studies are similar in their populations, methods, and outcomes, statistical techniques may be used for quantitative synthesis or meta-analysis. If studies are too diverse, findings are summarized using a narrative, or descriptive, synthesis.
Analysis Tools
- SPSS
- Industry-standard statistical analysis software with an intuitive interface for data management, descriptive statistics, hypothesis testing, regression, and advanced analytical methods. Download SPSS.
- JASP
- Point-and-click interface, t-tests, ANOVA, regression, descriptive statistics, Bayesian analyses, APA-style output. Free and open source.
- Jamovi
- Spreadsheet-style interface, descriptive statistics, regression, ANOVA, mixed models, add-on modules, powered by R. Free and open source.
Questions & Help
We assist with understanding and organizing your research and offer tailored guidance on search strategy, resource discovery tools, and other related resources. Contact your subject librarian to make an appointment.
Resources
Detailed guides to the systematic review process and published standards.
- Cochrane/Key Steps in a Systematic Review [online learning modules]
- Doing a Systematic Review: A Student’s Guide [print book]
- Cochrane Handbook for Systematic Reviews of Interventions [print book]