Scoping Review vs Systematic Review

A scoping review maps the evidence on a broad topic, showing what research exists, how it is spread and where the gaps lie. A systematic review answers a narrow question, usually whether an intervention works, by appraising and combining the best studies. The two methods answer different questions.

• 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.

Difference in Research Questions: Broad vs Narrow

The most fundamental difference between the research questions in scoping and systematic reviews is their breadth.

• Scoping reviews: These reviews explore broad research questions to map the existing literature, identify key concepts, types of evidence, and research gaps. They’re exploratory in nature and aim to provide a broad overview of the field.
• Systematic reviews: These reviews address narrow and specific research questions, aiming to provide precise answers based on a thorough analysis of the available evidence. Their focus on specific interventions and outcomes allows for a detailed synthesis of findings to inform practice, policy, and further research.

This distinction in research question scope is evident in the sources’ explanations and examples:

Scoping Review Question Examples:

• “What is known about HIV and rehabilitation?” This question explores a broad concept (“rehabilitation”) in the context of a specific health condition (HIV).
• “What is known from the existing literature about the effectiveness and cost-effectiveness of services to support carers of people with mental health problems?” This question seeks to understand the existing research landscape on a specific topic.

Scoping questions are usually framed with PCC: Population, Concept, and Context (Peters et al., 2015). Another example asks about the barriers and facilitators to accessing mental-health services among homeless veterans. The population is homeless veterans, the concept is barriers and facilitators, and the context is mental-health services.

Systematic Review Question Examples:

• “For women who have experienced domestic violence, how effective are advocacy programmes compared to other treatments on improving the quality of life?”

Systematic review questions are usually framed with PICO: Population, Intervention, Comparator, and Outcome. The example above compares advocacy programmes with other treatments on quality of life for women who have experienced domestic violence.

Scoping reviews, with their broad research questions, are beneficial when:

• Determining the feasibility of a systematic review: By mapping the breadth of evidence, researchers can assess whether there’s sufficient literature to warrant a full systematic review.
• Identifying research gaps: Scoping reviews can highlight areas where little or no research has been conducted, informing future research priorities.
• Clarifying key concepts and definitions: In fields with inconsistent terminology, scoping reviews can map out how different concepts are used, potentially proposing a unified understanding.

Systematic reviews are better suited for addressing well-defined clinical questions where the goal is to synthesize evidence to inform decision-making.

Difference in Synthesis of Findings: Descriptive vs Interpretative

The key element of any review is the synthesis. This is the process of bringing together findings from the included studies to draw conclusions from the body of evidence.

While both types of reviews involve collecting and summarizing data, systematic reviews aim to combine and analyze the results from different studies to answer the specific research question.

Scoping reviews

Scoping reviews provide a descriptive account of the available research, identifying key concepts, themes, and gaps in the existing knowledge base.

Data synthesis in a scoping review involves collating, combining, and summarizing findings from the included studies.

The synthesis is descriptive, not evaluative. A scoping review does not weigh the strength of the evidence or pool results into a single estimate.

Instead, it sorts studies into meaningful categories. Typical categories are research design, population characteristics, intervention types, outcome measures, and theoretical frameworks. A numerical summary of designs, populations and settings usually sits alongside a simple thematic analysis.

This categorization helps to make sense of a potentially large and diverse body of literature.

Systematic reviews

Systematic reviews provide a narrative synthesis that goes beyond simply summarizing individual studies.

A systematic review integrates and interprets the evidence in a transparent way. The result is a new understanding.

Interpreting results in context:

• The strength of the evidence: Conclusions should be drawn based on the overall quality and certainty of the evidence, considering factors like risk of bias, inconsistency, and imprecision.
• Potential biases: Systematic reviews explicitly address potential biases in the review process itself, such as limitations in the search strategy, study selection, or data extraction.
• Consistency with other evidence: Findings are discussed in the context of existing knowledge, comparing and contrasting with other systematic reviews or relevant research.

Drawing conclusions and implications: The final step involves summarizing the key findings and their implications for practice, policy, and future research. The conclusions should directly answer the research question, highlighting the strength of the evidence and any remaining uncertainties.

Meta-analysis: When appropriate, systematic reviews use statistical methods (meta-analysis) to combine the numerical results of similar studies, producing a pooled estimate of the intervention’s effect.

This quantitative synthesis allows for a more precise estimation of the effect size and helps address inconsistencies across individual studies.

How to Choose the Best Review for your Research Topic

According to Munn et al. (2018), the most important factor in choosing 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?

When to Choose a Systematic Review

Choose a systematic review to evaluate the feasibility, appropriateness, meaningfulness, or effectiveness of a treatment or practice (Munn et al., 2018). A decision will rest on the answer.

A typical question asks whether treatment A is more effective than treatment B for condition C in a given population.

The goal is a comprehensive, unbiased summary of the evidence that can be applied directly to clinical decision-making. The logic is convergent. Many studies are funneled toward a single, appraised answer.

Systematic reviews can also address patient experiences and economic considerations, not just effectiveness. They are often the foundation for evidence-based clinical practice guidelines. The Cochrane Handbook sets out the methods for reviews of interventions.

When to Choose a Scoping Review

Choose a scoping review to identify and discuss characteristics or concepts within the literature. It is not designed to generate direct clinical or policy recommendations.

Munn et al. (2018) describe several indications, including:

• Types of evidence: See what kinds of evidence exist and how research on a topic has been conducted, including designs, populations and settings.
• Extent and range: Map and characterize the literature to see how far it extends and how it is distributed.
• Knowledge gaps: Find what has and has not been studied, and set a research agenda.

Scoping reviews also help postgraduate students gain a broad understanding of a field and spot areas for deeper 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.

When a Scoping Review Is the Wrong Choice

A scoping review is the wrong tool for a focused question about whether a practice or intervention works. Such questions need the quality appraisal, and often the statistical pooling, of a systematic review (Munn et al., 2018).

Do not use it to dodge a demanding systematic review. Skipping appraisal produces a review that looks comprehensive but cannot support the effectiveness claims readers may infer from it.

Sometimes no new review is needed. A recent, high-quality systematic review may already cover the question.

Let the question choose the method. If it asks what is known and how that evidence is shaped, scope it. If it asks whether something works and how well, review it systematically.

Key Differences Between Scoping and Systematic Reviews

• 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.

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 (filing the written plan for the review before screening begins)	Open Science Framework (OSF)	PROSPERO
Grey Literature Search	Searched deliberately, including theses, reports, policy documents and trial registries (grey literature), so the map is not distorted by publication bias.	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.

The checklist has 27 items. They cover the rationale, objectives, eligibility criteria, search strategy, study selection process, data extraction methods, risk of bias assessment, data synthesis, and reporting of findings.

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.

The PRISMA-ScR was built by Delphi consensus. In a Delphi process, experts rate candidate items in rounds until they agree (Tricco et al., 2018a). A 24-member expert panel and two research leads took part, following the EQUATOR Network method for developing reporting guidelines.

The checklist has 20 essential items and 2 optional ones. Reporting critical appraisal of sources is optional, which sets scoping review reporting apart from systematic review reporting.

The checklist also covers charting, the scoping-review version of data extraction, in which key details of each source are recorded on a standard form.

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.

Scoping Review vs Narrative, Rapid, and Umbrella Reviews

Tricco et al. (2018b) compared the conduct and reporting quality of five types of knowledge synthesis: systematic, scoping, rapid, state-of-the-art narrative, and umbrella reviews. Each balances rigour, breadth and speed differently. None is simply a lesser version of another.

Scoping Review vs Narrative Review

A narrative review surveys a topic without a mandatory protocol, an exhaustive search, or explicit selection criteria. The author selects the literature by expertise and judgment.

That makes it efficient for building background, teaching, or presenting an expert argument. It is also the review type most vulnerable to selection bias, because two authors reviewing the same field may cite quite different studies.

A scoping review has the same broad scope but a documented, replicable process. It is the systematic, reproducible cousin of the narrative review.

Choose it when the map itself must withstand scrutiny, for instance because it will inform a funding or research-priority decision.

A narrative review discusses a topic. A scoping review maps it. A systematic review adjudicates a specific question about it.

Scoping Review vs Rapid and Umbrella Reviews

A rapid review streamlines the systematic review process to give an appraised answer within weeks rather than months. It may restrict the databases or date range searched, use a single reviewer for some screening stages, or abbreviate quality appraisal (Tricco et al., 2015).

It suits a decision-maker with a tight deadline who still needs an appraised answer to a narrow question, such as an emerging public-health threat.

It is not a faster scoping review. A rapid review shortens an effectiveness-focused process, whereas a scoping review asks a different question from the outset.

An umbrella review, or review of reviews, synthesizes the findings of several existing systematic reviews and meta-analyses on a related topic (Aromataris et al., 2015). It often compares interventions across outcomes or reconciles conflicting conclusions.

It fits once good-quality systematic reviews already exist. A scoping review fits earlier in the evidence lifecycle, when it is unclear how much primary research exists at all. An umbrella review has nothing to summarize until primary studies have first been systematically reviewed.

Critical Evaluation of Scoping Reviews

Scoping reviews fill a distinct niche. They bring the protocol, documented search and duplicate screening of the systematic review tradition to broad mapping questions. Narrative reviews once handled those questions informally (Arksey & O’Malley, 2005; Munn et al., 2018).

Used to current standards, the method is rigorous and valuable. Its main risks are superficiality, over-interpretation and misuse as a lighter systematic review.

Strengths of Scoping Reviews

A scoping review is uniquely suited to exploratory questions. Five features make the method valuable:

• Breadth: A wide, varied literature, including grey literature, can be covered, giving a panoramic overview that a narrowly focused systematic review cannot. This suits large, emerging or sprawling topics.
• Rigour: Unlike a narrative review, it uses a protocol, a documented search and duplicate screening, so the process is transparent and reproducible.
• Gap identification: Charting where evidence clusters and where it is absent helps identify knowledge gaps and set research priorities, which is why funders increasingly commission scoping reviews.
• Precursor role: It can show whether a systematic review is feasible and worthwhile, and refine its question and criteria, which reduces wasted effort on a premature review.
• Concept clarification: Where a term is used inconsistently, it can map the definitions and conceptual boundaries in play before anyone synthesizes findings.

Limitations of Scoping Reviews

Six limitations follow from the same design choices:

• Breadth over depth: A wide net risks superficiality. A scoping review shows what evidence exists, not how good it is or what it collectively concludes.
• No appraisal: Included studies are not critically appraised, so readers must not treat the map as an endorsement of the findings it lists.
• No pooled answer: Without an effect estimate, scoping reviews generally cannot support practice or policy recommendations.
• Inconsistent methods: Early frameworks left room for discretion, so conduct and reporting varied widely, and still do where standards are ignored.
• Heavy workload: Broad searches, grey literature and duplicate charting can be as labor-intensive as a systematic review.
• Misuse: Choosing a scoping review to avoid appraisal, then reading it as an effectiveness answer, is the greatest practical danger.

Contemporary Research

Recent work on the method reads as one argument. The field measured its own inconsistency, built standards to fix it, and is now refining them.

How Consistent Were Scoping Reviews?

As a duplicate-screened census of the whole method, this is strong methodological evidence. It turned a vague impression of inconsistency into documented fact.

Standards Built in Response

The PRISMA-ScR was the direct response. Reporting is more uniform where the checklist is applied.

In parallel, Peters et al. (2021b) updated the JBI conduct guidance to clarify when a scoping review is appropriate. It also aligns with the PRISMA-ScR, so the conduct and reporting halves of the method now fit together.

Adherence still lags behind availability. Peters et al. (2021a) caution that the label “scoping review” is sometimes used without regard to the available guidance. They name stakeholder engagement and consistent terminology as the next frontiers.

AI-Assisted Clustering

A very recent study extended the analysis stage. Hofmann et al. (2026) charted 684 distinct named therapeutic processes from 778 studies.

A large language model proposed candidate clusters from batches of process labels, and human raters corrected, merged and relabeled them over repeated rounds until 32 stable clusters emerged.

The largest cluster, common factors such as therapeutic alliance, held 20.6% of processes. Search, screening and reporting stayed conventional and human-led. The model only organized data already extracted, never selecting, appraising or interpreting studies.

It is an early example of how such tools might make mapping hundreds of inconsistently labeled concepts manageable.

References:

Arksey, H., & O’Malley, L. (2005). Scoping studies: Towards a methodological framework. International Journal of Social Research Methodology, 8(1), 19-32. https://doi.org/10.1080/1364557032000119616

Aromataris, E., Fernandez, R., Godfrey, C. M., Holly, C., Khalil, H., & Tungpunkom, P. (2015). Summarizing systematic reviews: Methodological development, conduct and reporting of an umbrella review approach. International Journal of Evidence-Based Healthcare, 13(3), 132-140. https://doi.org/10.1097/XEB.0000000000000055

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.

Hofmann, S. G., Pahlen, L., Westhoff, M., Hossner, K., Quintarelli, H., Usée, F., Stenzel, K., & Stangier, U. (2026). Processes in psychotherapy: A scoping review with LLM-assisted clustering. Clinical Psychology Review, 128, Article 102782. https://doi.org/10.1016/j.cpr.2026.102782

Levac, D., Colquhoun, H., & O’Brien, K. K. (2010). Scoping studies: Advancing the methodology. Implementation Science, 5(1), 69. https://doi.org/10.1186/1748-5908-5-69

Munn, Z., Peters, M. D. J., Stern, C., Tufanaru, C., McArthur, A., & Aromataris, E. (2018). Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Medical Research Methodology, 18(1), 143. https://doi.org/10.1186/s12874-018-0611-x

Munn, Z., Pollock, D., Khalil, H., Alexander, L., McInerney, 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. https://doi.org/10.11124/jbies-21-00483

Peters, M. D. J., Godfrey, C. M., Khalil, H., McInerney, P., Parker, D., & Soares, C. B. (2015). Guidance for conducting systematic scoping reviews. International Journal of Evidence-Based Healthcare, 13(3), 141-146. https://doi.org/10.1097/XEB.0000000000000050

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Peters, M. D. J., Marnie, C., Tricco, A. C., Pollock, D., Munn, Z., Alexander, L., McInerney, P., Godfrey, C. M., & Khalil, H. (2021b). Updated methodological guidance for the conduct of scoping reviews. JBI Evidence Implementation, 19(1), 3-10. https://doi.org/10.1097/XEB.0000000000000277

Tricco, A. C., Antony, J., Zarin, W., Strifler, L., Ghassemi, M., Ivory, J., Perrier, L., Hutton, B., Moher, D., & Straus, S. E. (2015). A scoping review of rapid review methods. BMC Medicine, 13, 224. https://doi.org/10.1186/s12916-015-0465-6

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Tricco, A. C., Lillie, E., Zarin, W., O’Brien, K. K., Colquhoun, H., Levac, D., Moher, D., Peters, M. D. J., Horsley, T., Weeks, L., Hempel, S., Akl, E. A., Chang, C., McGowan, J., Stewart, L., Hartling, L., Aldcroft, A., Wilson, M. G., Garritty, C., … Straus, S. E. (2018a). PRISMA extension for scoping reviews (PRISMA-ScR): Checklist and explanation. Annals of Internal Medicine, 169(7), 467-473. https://doi.org/10.7326/M18-0850

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