When planning a literature review, researchers often face a critical decision: scoping review or systematic review? While both approaches synthesize existing research, they serve different purposes and follow distinct methodologies. Understanding these differences is essential for selecting the right tool for your research question and ensuring your review delivers meaningful insights.

The Fundamental Distinction

Scoping reviews map the breadth and depth of available evidence on a topic, providing an overview of what research exists rather than synthesizing findings to answer specific questions. They're exploratory in nature, designed to identify gaps, clarify concepts, and explore emerging fields.

Systematic reviews, in contrast, synthesize high-quality evidence to provide definitive answers to focused clinical or research questions. They follow rigorous methodological standards to minimize bias and provide reliable conclusions for decision-making.

Think of scoping reviews as creating a "map" of the literature landscape, while systematic reviews provide detailed "directions" to specific destinations.

Core Differences: A Comparative Analysis

| Aspect | Scoping Review | Systematic Review | |--------|----------------|-------------------| | Purpose | Identify gaps, clarify concepts, explore emerging fields, map evidence breadth | Synthesize evidence for precise answers (e.g., intervention effects, diagnostic accuracy) | | Research Question | Broad (PCC framework: Population, Concept, Context) | Narrow (PICO framework: Population, Intervention, Comparator, Outcome) | | Quality Assessment | Optional or absent - focuses on relevance over rigor | Mandatory - uses tools like GRADE, Cochrane RoB, or JBI checklists | | Synthesis Approach | Descriptive charting, thematic analysis, no statistical meta-analysis | Quantitative (meta-analysis) or qualitative synthesis with statistical pooling | | Study Inclusion | Broad range of study designs and quality levels | Restricted to high-quality studies meeting methodological criteria | | Timeline | 2–6 months (efficient and focused) | 12–24 months (comprehensive and rigorous) | | Reporting Standards | PRISMA-ScR (Scoping Review extension) | PRISMA statement with additional extensions as needed |

When to Choose a Scoping Review

Scoping reviews are particularly valuable in several scenarios:

Exploring New or Emerging Fields

Concept clarification: When terms, definitions, or theoretical frameworks are unclear
Preliminary mapping: Understanding the scope and nature of research in developing areas
Stakeholder identification: Finding who is researching or affected by a topic

Informing Future Research

Research gap identification: Highlighting areas needing more investigation
Protocol development: Providing foundation for subsequent systematic reviews
Feasibility assessment: Determining if sufficient evidence exists for a full systematic review

Broad Policy or Practice Questions

Service delivery mapping: Understanding how interventions are implemented
Policy landscape analysis: Identifying existing policies and their evidence base
Educational program evaluation: Mapping educational interventions across contexts

When Systematic Reviews Are More Appropriate

Choose systematic reviews when you need:

Definitive answers to specific clinical or research questions
Effect size estimates through meta-analysis
High-confidence recommendations for practice or policy
Comprehensive quality assessment of included studies

Methodological Similarities and Differences

Shared Elements

Both review types emphasize:

Transparent methods clearly documented in protocols
Systematic searches across multiple databases
Reproducible processes with dual screening and extraction
Comprehensive reporting following established guidelines

Key Divergences

Question Formulation

Scoping: PCC framework focuses on broad exploration
- Population: Who is affected or who might benefit?
- Concept: What is the main idea or phenomenon?
- Context: What are the circumstances or settings?
Systematic: PICO framework targets specific interventions
- Population: Who is the target group?
- Intervention: What is being done?
- Comparator: What is being compared to?
- Outcome: What are the results?

Search Strategy

Scoping: Iterative searching to capture broad evidence
Systematic: Exhaustive searching with highly sensitive strategies

Study Selection

Scoping: Includes diverse study types and quality levels
Systematic: Applies strict methodological inclusion criteria

Data Extraction and Synthesis

Scoping: Charts study characteristics and themes descriptively
Systematic: Extracts data for statistical synthesis and quality assessment

Step-by-Step Guide to Conducting a Scoping Review

Step 1: Define Your Research Question

Use the PCC framework to formulate a broad, exploratory question that will guide your mapping of the evidence.

Step 2: Develop and Register a Protocol

Document your methods in advance (register with PROSPERO)
Define inclusion/exclusion criteria
Plan your search strategy and data extraction approach

Step 3: Conduct Systematic Searches

Search multiple databases and sources
Use iterative searching techniques
Include grey literature and unpublished sources

Step 4: Screen and Select Studies

Title/abstract screening for relevance
Full-text screening for eligibility
Document exclusion reasons

Step 5: Extract and Chart Data

Extract study characteristics (design, sample, methods)
Chart findings thematically
Identify patterns and gaps

Step 6: Report Results

Use PRISMA-ScR guidelines for reporting
Present descriptive summaries and thematic analyses
Discuss implications for future research

Tools and Resources for Scoping Reviews

Protocol Development

PROSPERO registration platform
PRISMA-ScR checklist and explanation document

Search and Screening

Covidence or EPPI-Reviewer for systematic processes
EvidenceTableBuilder.com for streamlined data extraction and charting

Analysis and Synthesis

NVivo or MAXQDA for thematic analysis
Excel or specialized software for data charting

Common Challenges and Solutions

Challenge: Maintaining Focus with Broad Questions

Solution: Use the PCC framework to provide structure while allowing flexibility for emerging findings.

Challenge: Managing Large Volumes of Diverse Evidence

Solution: Implement clear inclusion criteria and use purposive sampling if needed.

Challenge: Balancing Breadth with Feasibility

Solution: Define scope boundaries early and consider iterative searching approaches.

Challenge: Demonstrating Rigor Without Quality Assessment

Solution: Emphasize transparency, comprehensive searching, and stakeholder involvement.

The Relationship Between Scoping and Systematic Reviews

Scoping reviews often serve as precursors to systematic reviews:

Scoping Phase: Maps the evidence landscape and identifies high-quality studies
Systematic Phase: Conducts rigorous synthesis of the identified evidence

This staged approach ensures comprehensive coverage while maintaining methodological rigor.

Reporting Standards and Quality

PRISMA-ScR Guidelines

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) provides a 22-item checklist covering:

Title and abstract
Introduction and objectives
Methods (eligibility criteria, information sources, search, selection, data extraction, synthesis)
Results (selection of sources, characteristics, critical appraisal, synthesis of results)
Discussion (summary of evidence, limitations, conclusions)

Quality Considerations

While scoping reviews don't require formal quality assessment, they should demonstrate:

Transparency in methods and decision-making
Comprehensiveness in searching and inclusion
Reproducibility through detailed documentation
Stakeholder involvement for relevance and interpretation

Practical Considerations

Timeline and Resources

Timeframe: 2-6 months for most scoping reviews
Team size: 2-4 reviewers for efficient screening
Budget: Lower than systematic reviews due to less intensive quality assessment

Publication and Dissemination

Publish in journals accepting scoping reviews
Present findings at conferences
Use results to inform grant applications or policy development

Conclusion: Making the Right Choice

The decision between scoping and systematic reviews depends on your research question, available resources, and intended outcomes. Scoping reviews excel at mapping broad evidence landscapes and identifying research gaps, while systematic reviews provide definitive answers through rigorous synthesis.

Consider scoping reviews when:

Exploring new or emerging topics
Clarifying concepts or terminology
Informing future research directions
Providing overviews for stakeholders

Choose systematic reviews when:

Answering specific clinical questions
Conducting meta-analyses
Informing clinical guidelines or policy decisions
Requiring high-confidence evidence assessments

Both approaches contribute valuable insights to the evidence base. The key is selecting the methodology that best serves your research purpose and audience needs.

Key Resources:

PRISMA-ScR Guidelines: prisma-statement.org
Joanna Briggs Institute Scoping Review Guidance: joannabriggs.org
PROSPERO Registry: crd.york.ac.uk/prospero

Scoping Reviews vs. Systematic Reviews: Choosing the Right Approach