The following are key elements of a scoping review:
The PRISMA extension for scoping reviews was published in 2018. The checklist contains 22 items to include when completing a scoping review. Scoping reviews serve to synthesise 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.
Access the checklist, explanatory paper, introductory video and tip sheets.
A scoping review requires a well-defined objective and aligned research questions to provide coherence and direction. These elements guide the review process, including setting criteria for inclusion and exclusion, developing a search strategy, and directing data extraction and analysis. The objective outlines the goals, rationale, and achievements desired from the review, such as mapping existing literature and identifying knowledge gaps. Research questions, derived from the objectives, offer a focused roadmap and should be clear, concise, and relevant. Frameworks like PCC (Population, Concept, Context) help in developing these objectives and questions, by defining the specific group or entities (Population), the central idea or topic (Concept), and the relevant setting or circumstances (Context).
What were the unintended consequences of measures taken in the UK school setting to prevent and manage the spread of Covid-19?
Population - Children, teachers
Concept - Covid-19 mitigation consequences
Context - UK schools
Other frameworks include PICO, SPICE, and SPIDER. See the Systematic reviews guide for more information.
Refer to PRISMA-ScR item 3 Rationale and item 4 Objectives.
A research protocol is a detailed plan outlining the methodology for a review, including documenting results, search strategy, and stating objectives. It should be created to ensure transparency and reproducibility. While not mandatory, registering the protocol is highly recommended to promote transparency, reduce duplication, and prevent publication bias. The platform Open Science Framework (OSF) is an option for registration. Some journals accept scoping review protocols for publication, but PROSPERO does not currently accept them.
Refer to PRISMA-ScR item 5 Protocol and registration.
This step involves developing and aligning the eligibility criteria with the objectives and questions of the scoping review. Transparent and well-justified eligibility criteria are essential for ensuring replicability and allowing readers to assess the relevance of included sources. When reporting these criteria, clarity and justification should be emphasised, with a clear link to the review’s objectives.
Eligibility criteria are commonly known as inclusion criteria and exclusion criteria. Inclusion criteria are the elements of an article that must be present for it to be eligible for inclusion in a review. Exclusion criteria are the elements of an article that disqualify the study from inclusion in a review.
Ensure that the eligibility criteria are comprehensive enough for effective screening to retrieve the desired number of studies. If they're not, you may need to adjust them based on the initial search results—it's an iterative process.
Check if there are specific papers you want included in your review and verify if they appear in your search results.
Refer to PRISMA-ScR item 6 Eligibility criteria
Specific restrictions, such as date range, language, or publication status, also require clear justification to ensure the inclusion of the most relevant and current evidence while acknowledging the limitations imposed by these restrictions.
Eligibility criteria for a study typically include several key components:
Using this framework ensures comprehensive, well-defined eligibility criteria for a focused literature synthesis. Even if not explicitly stated, a systematic approach might still be applied through other methods.
Scoping reviews aim to provide a comprehensive overview by identifying a broad range of relevant studies, including both published and unpublished literature, rather than being exhaustive like systematic reviews. They may use various information sources, such as scholarly databases, unpublished literature, conference papers, books, and expert consultations. The search strategy and execution should be reported, including who developed it and the date of the most recent search. The following are suggested resources to use for a scoping review.
Make a comprehensive list of all databases you used; scoping reviews typically search a minimum of three academic journal article databases which cover the disciplines represented by your research objectives. If there are more nuanced concepts in your research questions, you may need to search even more databases.
Expansive searches can include grey literature databases, conference proceedings, unpublished reports, theses, clinical trial databases, and author-specific searches.
A method used to ensure a comprehensive understanding of the research landscape by reviewing the reference lists of included studies and examining articles that cite those studies. This process can help identify additional relevant literature that might not have been captured through initial database searches.
If contacting experts in in the field for additional sources, document this in detail.
Refer to PRISMA-ScR item 7 Information sources
Selecting evidence for a scoping review involves a systematic process where articles are screened against predefined eligibility criteria to identify relevant studies. This process may not capture all available evidence due to search limitations. The emphasis is on mapping literature and identifying research gaps, rather than assessing the quality of studies. Two reviewers should independently screen titles and abstracts to remove duplicates and irrelevant studies.
The process of initial screening and assessment in a scoping review involves several key steps:
Initial Screening of Titles and Abstracts: After applying a search strategy, reviewers screen the titles and abstracts of identified articles against predefined inclusion and exclusion criteria. The aim is to identify potentially relevant studies while excluding those clearly outside the review's scope. At this stage, reviewers should prioritise over-inclusion to minimise the risk of excluding potentially valuable studies.
Retrieving and Assessing Full Texts: For studies where relevance cannot be determined from the title and abstract alone, reviewers should obtain the full text for comprehensive assessment against the criteria. This involves a detailed review of each potentially relevant study to definitively determine its eligibility.
Resolution of Disagreements: If there is disagreement between reviewers about a study's eligibility, a predefined strategy should be in place. This could involve consensus-building discussions or arbitration by a third reviewer to reach a final decision. This collaborative approach ensures a fair and impartial selection process and enhances the review's reliability.
Refer to PRISMA-ScR item 9 Selection of sources for evidence
Charting, or data extraction, is essential in conducting a scoping review. It involves systematically collecting information from sources using a structured form, with at least two reviewers independently extracting data.
Unlike systematic reviews, which focus on synthesising results and assessing study quality, scoping reviews aim to map existing literature, identify key concepts, themes, and research gaps. As a result, data charting in scoping reviews is broader and includes a wider range of data items. This process helps characterise and summarise research evidence, highlighting research gaps.
Refer to PRISMA-ScR item 10 Data charting process
To standardise source selection in scoping reviews, a structured form is crucial. This form, aligned with eligibility criteria, should include clear questions and specify software like Covidence or EndNote.
A calibration exercise is recommended before screening, involving testing the form with a sample of five - ten citations. This helps resolve inconsistencies, which are discussed and refined in a roundtable discussion. If needed, a second calibration can ensure at least 70%-80% agreement.
During the full screening process, at least two reviewers should independently screen sources. Duplicates must be managed, and disagreements resolved through consensus or a third reviewer. The scoping review should include a detailed narrative description of the charting process, covering reviewers involved, duplicate management, software used, resolution of disagreements, and rationale for source exclusion.
Include the final charting form, with clear definitions for each item, as an appendix or supplementary file in the scoping review if possible. Key data items to chart can include authors, publication year, origin, study aims, population, methodology, outcomes, and key findings.
Refer to PRISMA-ScR item 11 Data items
When summarising evidence in research, present findings clearly and logically to address research questions. Use tables, figures, or narrative summaries to illustrate data. A narrative summary should be clear and concise, providing a comprehensive overview of current knowledge. Highlight known facts and areas needing further exploration. Integrate information from multiple sources into a cohesive narrative, focusing on necessary actions, discontinuations, or the lack of evidence for efficacy. Use headings and subheadings to organise information logically, aiding understanding of the evidence and its connections.
In a scoping review, focus on mapping existing evidence, identifying knowledge gaps, and clarifying concepts, rather than making practice or policy recommendations, which are typical in systematic reviews. Summarise key findings in relation to research questions, highlighting themes or patterns and elucidating nuances in evidence. Discuss evidence consistency for clear takeaways. Note that scoping reviews aim to map evidence without evaluating result quality. Identify gaps and suggest research questions or study designs to address them. This guidance informs future research, often leading to more focused systematic reviews.
Refer to PRISMA-ScR: item 18 Synthesis of results, item 19 Summary of evidence, item 20 Limitations and item 21 Conclusions
To ensure you have covered all the steps there are flow chart templates available from both the JBI Scoping Review Network and PRISMA.
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