The “inclusion criteria” of the protocol details the basis on which sources will be considered for inclusion in the scoping review and should be clearly defined. These criteria provide a guide for the reader to clearly understand what is proposed by the reviewers and, more importantly, a guide for the reviewers themselves on which to base decisions about the sources to be included in the scoping review. As explained in Section 11.2.2, as for other review types, there must be clear congruence between the tile, question/s, and inclusion criteria of a scoping review.
Types of participants
Important characteristics of participants should be detailed, including age and other qualifying criteria that make them appropriate for the objectives of the scoping review and for the review question.
In some circumstances, participants per se are not a relevant inclusion criterion. For example, for a scoping review that is focused upon mapping the types and details of research designs that have been used in a particular field, it may not be useful or within scope to detail the types of participants involved in that research.
The core concept examined by the scoping review should be clearly articulated to guide the scope and breadth of the inquiry. This may include details that pertain to elements that would be detailed in a standard systematic review, such as the “interventions”, and/ or “phenomena of interest”, and/or “outcomes” (as relevant for the particular scoping review).
For example, the overarching concept of interest for the above scoping review is quality of life questionnaires that are used following tonsillectomies with or without adenoidectomies for chronic infection or sleep-disordered breathing.
Further elements of this overarching concept may be of importance to this review. For example, the format (e.g. paper or web-based) and contents (i.e. assessment domains) of the included instruments. The validity and reliability (i.e. if and how they have been psychometrically tested) may also be of interest for mapping.
Outcomes may also be a component of a scoping review’s “Concept”. If outcomes of interest are to be explained, they should be linked closely to the objective and purpose for undertaking the scoping review. For example, this scoping review could also identify and map the outcomes of quality of life assessments and/or the outcomes of the psychometric testing of the tools themselves.
The “Context” element of a scoping review will vary depending on the objective/s and question/s of the review. The context should be clearly defined and may include, but is not limited to, consideration of cultural factors, such as geographic location and/or specific social, cultural, or gender-based interests. In some cases, context may also encompass details about the specific setting (such as acute care, primary health care or the community). Reviewers may choose to limit the context of their review to a particular country or health system or healthcare setting, depending on the topic and objectives.
The context of the review in the example provided above has not been stated explicitly (i.e. it could be described to be ‘open’) as sources of evidence pertaining to any contextual setting would be eligible for inclusion. However, a context could be imposed to refine the scope of the review in different ways. For example; only within middle-high income countries or only within primary care settings.
Types of evidence sources
For the purposes of a scoping review, the “source” of information can include any existing literature, e.g. primary research studies, systematic reviews, meta-analyses, letters, guidelines, websites, blogs, etc. Reviewers may wish to leave the source of information “open” to allow for the inclusion of any and all types of evidence. Otherwise, the reviewers may wish to impose limits on the types of sources they wish to include. This may be done on the basis of having some knowledge of the types of sources that would be most useful and appropriate for a particular topic. For example, the scoping review example on quality of life questionnaires available for pediatric patients following tonsillectomies with or without adenoidectomies for chronic infection or sleep-disordered breathing sought quantitative studies, specifically; experimental and epidemiological study designs including randomized controlled trials, non-randomized controlled trials, quasi-experimental, before and after studies, prospective and retrospective cohort studies, case-control studies, and analytical cross-sectional studies. Qualitative studies, reviews, and conference abstracts were excluded.