What is the purpose of a scoping review?

The purpose of a scoping review is to identify the types of available evidence in a given area; summarise the existing evidence; identify gaps in the literature; and make recommendations for future research.2 In recent years, scoping reviews have become increasingly popular among nurses and other healthcare professionals. For example, a PubMed search of the term ‘scoping review’ yielded 53 309 results as of January 2024—more than double the results from just 4 years ago. Unlike a systematic review, a scoping review is not intended to inform clinical guidance, policy and practice.3 A scoping review aims to provide a descriptive summary of the sources of evidence without necessarily assessing the quality of the sources. Therefore, assessing the quality and risk of bias of the included studies is not required, however, some researchers choose to do so. Importantly, scoping reviews should be conducted systematically and transparently and be reproducible. It is recommended that a university or hospital librarian should assist with the development of a search strategy.

Scoping review methodology

While a scoping review differs in meaningful ways from a systematic review, it still uses a rigorous and systematic approach to evidence synthesis. Evidence synthesis describes the process of collecting and combining data from multiple sources—usually from existing research—to provide a summary of the current evidence. Scoping reviews need to be reported according to a rigorous methodology that has been refined over the past two decades.2 4–6 These include the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) and the Joanna Briggs Institute (JBI) methodology for scoping reviews. The PRISMA-ScR outlines a 22-item checklist—of which 20 are essential and 2 are optional—that researchers should follow when planning and writing up their scoping review. To aid researchers new to the scoping review methodology, PRISMA7 provides a tip sheet and examples of best practices for each item on the checklist. Additionally, JBI8 has provided a template to assist researchers in developing a scoping review protocol and scoping review. This can be useful for understanding the various steps required to undertake a scoping review. While not mandatory, it is considered best practice to register the scoping review protocol on a registry such as the Open Science Framework. Some journals may expect a scoping review protocol to have been published before they will consider it for publication. A protocol is the plan for your scoping review, and it should include the following details: key definitions, aims, rationale for the review, eligibility criteria, types of literature that will be searched and an explanation of how the data will be presented.

Key steps of a scoping review

The key steps in a scoping review are as follows:

• Identifying clear aims, objectives and research question/s.

• Developing a protocol (eg, including eligibility criteria, screening process, search strategy and selecting databases to search).

• Conducting a systematic search of the literature.

• Managing results using citation management software (eg, EndNote, Mendeley).

• Screening results that meet the eligibility criteria.

• Charting the data.

• Analysing the evidence.

• Writing up the evidence.

• Presenting findings.

Having clear aims, objectives and research question/s is essential for conducting a coherent scoping review. The population, concept and context framework can be a useful guide for developing comprehensive eligibility criteria and ensuring that the research question is clear.6 Developing a protocol will help clarify the kinds of studies that will be eligible for inclusion, the process of screening and the search terms that will be used to identify relevant sources. A search strategy will include but is not limited to the keywords, Boolean operators (eg, AND, OR, NOT) and the specific fields (eg, author, title, abstract) that will be used to search for sources that meet the eligibility criteria. It is also worth searching to see if anyone has published a scoping review protocol that might have or has explored a similar research question. The databases that are searched will depend on the topic of the research question, but in healthcare, it is common to search some of the following databases: PubMed (includes MEDLINE); Cumulative Index to Nursing and Allied Health Literature; Embase; Scopus; and ScienceDirect.

While there may be some overlap when searching the different databases, it is important to search more than one database. Given the broad nature of a scoping review, it is common to use additional search methods such as a manual search of the reference list of included studies and the grey literature. Grey literature is evidence that has not been commercially published (eg, in a journal) and can include public policy documents, government reports and PhD thesis. Once the searches are complete, the results should then be reviewed, documented and managed using citation management software. The search results will then need to be screened against the eligibility criteria. The first step will include reading the titles and abstracts and identifying sources that will require full-text screening. The second step will require reading the full text of those sources that were considered to meet the eligibility criteria following initial screening—a team approach is recommended. Following this, a decision must be made about what sources should be included in the scoping review based on the inclusion and exclusion criteria. The next step is data charting, which describes extracting relevant information from eligible studies into a descriptive summary. This requires the use of a data charting form where appropriate information can be recorded—importantly, only information relevant to the objectives and research question should be charted. Some of the following information is considered key for data charting9:

• Author(s).

• Year of publication.

• Origin/country of origin (where the study was published or conducted).

• Aims/purpose.

• Study population and sample size (if applicable).

• Methodology/methods.

• Intervention type/duration, comparator and outcome measures (if applicable).

• Key findings that relate to the scoping review question/s.

Analysis of the extracted evidence should be descriptive and can be organised into categories using basic coding and frequency counting.10 Where appropriate to the objectives, basic qualitative content analysis can also be used.6 The evidence can be presented in several different ways including tables, diagrams, bubble charts and a narrative format—many researchers use a combination of the different presentations. Tables and charts might record the distribution of the year of publication, countries where the studies were conducted and the journals the studies were published. Finally, the last step is to present the findings by writing and reporting it according to transparent standards. An additional benefit of writing up the scoping review according to recognised criteria is that the review is unlikely to require too much additional work to format for submission to a journal.

Ethics approval

Not applicable.