Systematic Review versus Scoping Review: A Guide for Researchers
Table of contents
Understanding systematic reviews and scoping reviews
When to conduct a systematic review
Core elements of a systematic review
When to conduct a scoping review
Key features of a scoping review
Systematic review vs scoping review: An overview
Sourcing specialized expertise for systematic or scoping reviews
In academic research, healthcare, clinical practice, and other evidence-based fields, synthesizing published literature is an important step before launching clinical trials, conducting experiments, updating treatment guidelines, or applying for research grants. Systematic reviews and scoping reviews are two commonly used methods [1] for gathering and analyzing existing literature.
During study design, researchers often find it difficult to decide whether to choose a systematic review or a scoping review. While both follow structured, transparent, and reproducible steps, their core objectives are different. Choosing the wrong approach could lead to misapplied methodology, unnecessary rework, or even rejection at peer review or regulatory submission.
Understanding systematic reviews and scoping reviews
According to the Cochrane Handbook for Systematic Reviews of Interventions [2], a systematic review “attempts to collate all the empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question.” Thus, a systematic review helps extract information about the current state of knowledge/research about a specific intervention or healthcare topic.
A scoping review, on the other hand, takes a broader view. It explores a wide or emerging body of evidence to clarify concepts, map how research has been conducted across a field, and identify gaps in the literature. The objective of a scoping review is not to evaluate the clinical effectiveness of a specific intervention, but to document the volume, nature, and characteristics of the available evidence.
When to conduct a systematic review
According to Munn et al. [3], a systematic review should be chosen when the existing literature is mature enough to address specific questions regarding the feasibility or effectiveness of a clinical intervention or policy.
Core elements of a systematic review
- A focused research question: Systematic reviews follow structured formats such as PICO (Population, Intervention, Comparison/s, Outcome) or PECO (Population, Exposure, Comparator, and Outcomes) [4] to establish clear eligibility criteria.
- A registered protocol: Researchers write a protocol detailing their search strategy and register it on databases such as PROSPERO [5] to prevent outcome reporting bias and avoid research duplication.
- Exhaustive literature searches: Reviewers run comprehensive searches across multiple databases (such as PubMed, Embase, and Cochrane Library) as well as grey literature. This is followed by dual independent screening.
- Mandatory critical appraisal: Every study included in a systematic review undergoes a risk of bias assessment [6] using validated tools [7], to determine the reliability of the underlying evidence.
- Quantitative or narrative synthesis: Depending on data consistency across included studies, authors either calculate pooled effect sizes through statistical meta-analyses or present findings through a structured narrative synthesis following the PRISMA 2020 statement [8].
Because a systematic review critically appraises study validity, its conclusions help shape clinical practice guidelines and regulatory approvals.
When to conduct a scoping review
Scoping reviews map the volume and characteristics of research across an entire field. When a topic is emerging or conceptually varied, researchers use this methodology to clarify definitions, generate hypotheses, and determine whether a full systematic review is required or feasible.
Key features of a scoping review
- The scope of questions: Scoping reviews focus on broad, exploratory questions that typically follow the PCC (Population, Concept, Context) framework [9] to capture evidence across diverse study designs, patient groups, and care settings.
- Iterative search and data charting: Under this methodology, researchers screen a wide variety of sources, including peer reviewed papers, policy documents, and clinical guidelines, mapping study characteristics and thematic trends onto a structured charting form.
- Absence of mandatory quality appraisal: Scoping reviews do not typically include formal risk of bias assessments. The primary goal is to map all available evidence [3] on a topic and not evaluate its methodological quality.
- Descriptive and thematic presentation: Findings of a scoping review are summarized through visual charts, descriptive statistics, and conceptual maps following the PRISMA-ScR reporting checklist [10].
A well-executed scoping review provides a comprehensive understanding of the field.
Systematic review vs scoping review: An overview
Here’s a brief overview of systematic reviews and scoping reviews.
| Feature | Systematic review | Scoping review |
| Primary objective | Answer a specific question to guide clinical or policy decisions | Map evidence, clarify concepts, and identify research gaps |
| Structure of questions | Precise and defined as per specific frameworks (e.g., PICO or PECO) | Broad and exploratory (PCC framework) |
| Search protocol registration | PROSPERO, Open Science Framework, or publication | Open Science Framework or published protocol (PROSPERO currently excludes scoping reviews) |
| Quality appraisal | Mandatory risk of bias assessment for all included studies | Optional and typically omitted |
| Data synthesis | Meta analysis or structured narrative synthesis | Qualitative charting, descriptive tables, and thematic summaries |
| Reporting guideline | PRISMA 2020 statement | PRISMA-ScR extension |
| Primary outcome | Actionable recommendations on intervention safety or efficacy | Conceptual overview, evidence gap analysis, or feasibility findings |
Sourcing specialized expertise for systematic or scoping reviews
Whether a project requires a focused systematic review or an exploratory scoping review, both methodologies demand significant operational bandwidth and specialized competencies. Designing complex search strings across multiple databases, conducting dual independent screening, appraising risk of bias, and charting heterogeneous data are technical skills rooted in formal research methodology and evidence-based practice.
Most research teams do not maintain full-time specialists across these areas. This gap could impact both project timelines and output quality. For academic groups facing tight grant or journal deadlines, rushed searches or uncalibrated screening protocols could lead to peer review rejection. For medical device manufacturers preparing literature reviews for Clinical Evaluation Reports (CERs) [11] under the EU MDR [12] or for pharmaceutical teams compiling Health Technology Assessment (HTA) [13] dossiers, methodological oversights can lead to multiple deficiency questions and stall commercial progress.
Because comprehensive systematic or scoping reviews are typically needed intermittently, building permanent in-house teams is rarely practical. Platforms like Kolabtree [14] connect academic researchers, MedTech companies, and pharma R&D teams directly with vetted freelance specialists in review methodology, information science, and biostatistics. Bringing in fractional expertise for targeted milestones such as search strategy validation, secondary screening, or statistical meta-analysis enables teams to deliver rigorous, compliant reviews systematic and scoping reviews.
References
1. Scoping Review vs Systematic Review: Understanding The Difference. Laser AI. Evidence Prime. https://www.laser.ai/blog-posts/systematic-review-versus-scoping-review. Accessed 01 September 2026.
2. Cochrane Handbook for Systematic Reviews of Interventions https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-01#section-1-1
3. Zachary Munn et al. Systematic Review or Scoping Review? Guidance for Authors when Choosing between a Systematic or Scoping Review Approach. BMC Med. Res. Methodol. 2018; 18(1): 143. doi:10.1186/s12874-018-0611-x.
4. Rebecca L.M. et al. Identifying the PECO: A Framework for Formulating Good Questions to Explore the Association of Environmental and Other Exposures with Health Outcomes. Environ Int. 2018; 121(Pt 1):1027-1031. doi:10.1016/j.envint.2018.07.015.
5. What is PROSPERO? National Institute for Health and Care Research. https://www.crd.york.ac.uk/prospero/. Accessed 03 September 2026.
6. Systematic Review and Evidence Synthesis: What is Risk of Bias Assessment? University of Minnesota Libraries. https://libguides.umn.edu/c.php?g=1264119&p=9285838. Accessed 03 September 2026.
7. Aaron M.D., Patrick F., An-Wen C. Research Techniques Made Simple: Assessing Risk of Bias in Systematic Reviews, J. Invest Dermatol. 2016; 136(11), e109-e114, ISSN 0022-202X. doi:10.1016/j.jid.2016.08.021.
8. Matthew J.P. et al. The PRISMA 2020 Statement: An Updated Guideline for Reporting Systematic Reviews. BMJ 2021; 372 :n71 doi:10.1136/bmj.n71.
9. Scoping Reviews. What is PCC? Adelaide University LibGuides. https://au.libguides.com/scopingreviews/applypcc. Accessed 06 September 2026.
10. Andrea C. T. et al. PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and Explanation. Ann. Intern. Med. 2018. 169:467-473. doi:10.7326/M18-0850
11. The Importance of Clinical Evaluation Reports. eLeaP. https://quality.eleapsoftware.com/the-importance-of-clinical-evaluation-reports-in-research/. Accessed 06 September 2026.
12. Consolidated Text: Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on Medical Devices, Amending Directive 2001/83/EC, Regulation (EC) No 178/2002 and Regulation (EC) No 1223/2009 and Repealing Council Directives 90/385/EEC and 93/42/EEC (Text with EEA relevance). EUR-Lex. https://eur-lex.europa.eu/eli/reg/2017/745/2024-07-09/eng. Accessed 06 September 2026
13. Health Technology Assessment. World Health Organization. https://www.who.int/health-topics/health-technology-assessment#tab=tab_1. Accessed 05 September 2026.
14. Freelance Literature Search Experts. Kolabtree. https://www.kolabtree.com/services/literature-search. Accessed 07 September 2026.
