- Systematic reviews are designed to answer specific research questions with the goal of synthesizing evidence to inform clinical practice or policy decisions, such as determining the effectiveness of an intervention.
- Scoping reviews are valuable tools for exploring broader research landscapes, clarifying concepts, and identifying research gaps.
How to Choose the Best Review for your Research Topic
The Cochrane Handbook states that the primary factor in deciding between a systematic review and a scoping review is the authors’ intention:
Do they aim to use the review’s results to answer a clinically meaningful question or to inform practice?
A systematic review is recommended if the objective is to evaluate the feasibility, appropriateness, meaningfulness, or effectiveness of a treatment or practice.
For example, “Is treatment A more effective than treatment B for condition C in population D?”
The goal is to produce a comprehensive, unbiased summary of the available evidence that can be directly applied to clinical decision-making.
Systematic reviews can address various aspects of healthcare beyond just effectiveness, including patient experiences and economic considerations.
They are often the foundation for developing evidence-based clinical practice guidelines.
Conversely, a scoping review is suitable when the focus is on identifying and discussing specific characteristics or concepts within the literature rather than generating direct clinical or policy recommendations.
Scoping reviews can be an excellent way for postgraduate students to gain a broad understanding of a field or to identify potential areas for more in-depth research.
If a research area has inconsistent terminology or definitions, a scoping review can map out how different concepts are used and potentially propose a unified understanding. This can help refine the focus and scope of a subsequent systematic review.
Key differences:
- Systematic reviews aim to answer a specific question and typically involve a more rigorous, comprehensive search and analysis of the literature, including a detailed quality assessment of included studies.
- Scoping reviews aim to map the key concepts and types of evidence available on a topic. While they follow a systematic approach, they typically do not include the same level of critical appraisal as systematic reviews.
- Scoping reviews often have broader, more exploratory objectives than the focused question(s) in systematic reviews.
- Scoping reviews map the available evidence, while systematic reviews synthesize and evaluate the evidence.
- Scoping reviews typically use narrative synthesis, while systematic reviews may include meta-analysis.
- Scoping reviews often identify research gaps, while systematic reviews focus on informing practice and policy.
- Unlike scoping reviews, systematic reviews aim to be exhaustive within their defined scope, capturing all relevant evidence on a particular question.
- Critical appraisal of individual studies is optional in scoping reviews but essential in systematic reviews.
- Scoping reviews can be used as a preliminary step to a systematic review, helping to identify the types of evidence available, potential research questions, and relevant inclusion criteria.
- Due to their rigorous methodology, systematic reviews are generally more time-consuming, often taking 12-24 months to complete, while scoping reviews can usually be completed more rapidly, typically within 2-6 months.
If the goal is to determine the effectiveness of an intervention:
Systematic reviews evaluate the effectiveness of a particular intervention for a specific condition while scoping reviews map the research landscape by:
- Examining the range of interventions for a health condition.
- Identifying types of studies conducted.
- Noting populations studied.
- Summarizing outcomes measured.
Scoping reviews help identify areas needing further research, whereas systematic reviews aim to draw conclusions about intervention effectiveness.
| Scoping Reviews | Systematic Reviews | |
|---|---|---|
| Purpose | Exploratory, providing a descriptive overview of the research landscape. | Aims to provide a rigorous and unbiased answer to a specific research question. |
| Question Framework | PCC (Population, Concept, Context) | PICO (Problem/Population, Intervention, Comparison Intervention, Outcome) |
| Example Question | How do cultural beliefs and practices (C-context) influence the ways in which parents (P-parents of children with physical disabilities) perceive and address (C-concept) their children’s physical disabilities? | For women who have experienced domestic violence (P), how effective are advocacy programs (I) compared to other treatments (C) in improving the quality of life (O)? |
| Search Strategy | Designed to be inclusive rather than exhaustive, capturing a wide range of sources. | Comprehensive and systematic, aiming to minimize bias and identify all relevant studies, |
| Protocol Registration | Open Science Framework (OSF) | PROSPERO |
| Grey Literature Search | Not usually included | Usually included |
| Data Items | Typically broader, including study characteristics, concepts, interventions, methodologies, and key findings. | More specific, often focusing on study design, participants, interventions, outcomes, and risk of bias assessment. |
| Data Analysis | Primarily descriptive, focusing on summarizing characteristics and identifying themes and trends. | Create a new understanding by synthesizing and interpreting the available evidence. This can include statistical meta-analysis to combine results from multiple studies. |
| Quality Assessment | Typically not a primary focus. | Rigorous assessment of study quality is essential using standardized tools to minimize bias in the findings. |
| Reporting Standard | PRISMA-ScR | Standard PRISMA |
Standardized Reporting Guidelines
The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist is tailored for reporting systematic reviews and meta-analyses.
It consists of 27 items covering aspects such as the rationale, objectives, eligibility criteria, search strategy, study selection process, data extraction methods, risk of bias assessment, data synthesis, and reporting of finding.
PRISMA helps researchers communicate their methods and findings more effectively, ultimately improving the reliability and usefulness of systematic reviews for informing healthcare decisions.
The PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) checklist builds upon the PRISMA checklist but is specifically designed for reporting scoping reviews.
It includes additional items relevant to scoping reviews, such as charting methods, stakeholder consultation, and the presentation of a broader range of evidence sources beyond empirical studies.
References:
Arksey, H., & O’Malley, L. (2005). Scoping studies: towards a methodological framework. International Journal of Social Research Methodology, 8(1), 19-32.
Centre for Reviews and Dissemination (CRD). (2001). Undertaking systematic reviews of research on effectiveness: CRD’s guidance for those carrying out or commissioning reviews. York: University of York.
Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.4 (updated August 2023). Cochrane, 2023. Available from www.training.cochrane.org/handbook.
Levac, D., Colquhoun, H., & O’Brien, K. K. (2010). Scoping studies: advancing the methodology. Implementation Science, 5(1), 69.
Munn, Z., Pollock, D., Khalil, H., Alexander, L., Mclnerney, P., Godfrey, C. M., … & Tricco, A. C. (2022). What are scoping reviews? Providing a formal definition of scoping reviews as a type of evidence synthesis. JBI evidence synthesis, 20(4), 950-952.
