01 · The Question
Should Your Review Synthesize an Answer or Map What Is Known?
You want to conduct a rigorous review, but your question could plausibly lead to either a systematic review or a scoping review. Both may involve protocols, comprehensive searching, explicit eligibility criteria, structured screening, data extraction, and transparent reporting. So where is the dividing line?
The distinction is primarily about purpose.
A systematic review typically seeks to answer a defined question by identifying and synthesizing the evidence relevant to that question. A scoping review usually asks a broader question about the extent, characteristics, concepts, definitions, methods, or types of evidence available in a field.
Choosing between them therefore requires more than asking whether your topic is "broad" or "narrow." You need to decide what you want to learn from the literature and what kind of conclusion your review is intended to support.
02 · The Short Answer
Choose the Review According to What You Need the Evidence to Do
In Brief
Use a systematic review when you need to answer a specific question by systematically identifying, evaluating, and synthesizing relevant evidence. Use a scoping review when you need to map the breadth, characteristics, concepts, or types of evidence in a field, clarify how research has been conducted, identify knowledge gaps, or determine whether a more focused systematic review may be warranted.
Both approaches can be systematic and transparent in how they search for and select evidence. The crucial difference is the review objective, which in turn affects the question, eligibility criteria, data extraction, appraisal, and synthesis.
03 · What You Need to Know
How Systematic and Scoping Reviews Differ
A Systematic Review Usually Seeks an Answer to a Defined Question
Systematic reviews use explicit methods to identify, select, appraise where appropriate, and synthesize evidence relevant to a prespecified question. The question determines what evidence is eligible and what information needs to be extracted from the included studies.
Many familiar systematic reviews concern intervention effectiveness: Does intervention A improve outcome B compared with intervention C in population D? Systematic reviews are not limited to intervention effects, however. Depending on the methodology, they can investigate prevalence, diagnostic accuracy, prognosis, etiology, qualitative experiences, economic questions, and other forms of evidence.
The defining feature is not a particular subject or statistical technique. It is the use of systematic review methods to answer the specified question through a defensible body of evidence.
A Scoping Review Usually Maps the Evidence Landscape
A scoping review is useful when you first need to understand what evidence exists and how that evidence is distributed or conceptualized. PRISMA describes scoping reviews as evidence syntheses that assess the scope of literature on a topic and notes that they can help determine whether a systematic review is warranted.
A scoping review might examine what types of interventions have been studied, which populations appear in the literature, how a concept has been defined, what research designs researchers have used, which outcomes have been measured, where studies have been conducted, or where apparent evidence gaps remain.
JBI guidance accordingly distinguishes the typically precise inclusion criteria of a systematic review from the broader scope and less restrictive inclusion criteria often used in a scoping review.
Feature
Systematic Review
Scoping Review
Typical purpose
Answer a defined question through synthesis of relevant evidence
Map or characterize the extent, nature, concepts, or distribution of evidence
Typical question
Usually focused and analytically specific
Usually broader and exploratory or descriptive
Common question framework
Depends on review type; PICO is common for intervention questions
PCC, meaning Population, Concept, and Context, is commonly used in JBI scoping reviews
Protocol
Prospective protocol is good practice and may be required by the chosen methodology or organization
An a priori protocol is expected in JBI methodology
Search
Systematic and designed to identify eligible evidence
Systematic and generally broad enough to capture evidence relevant to the scope
Critical appraisal
Commonly important to interpreting the evidence, depending on the review methodology
May be conducted, but is not necessarily required for every scoping review objective
Typical synthesis
May include quantitative, qualitative, narrative, or other structured synthesis
Often descriptive mapping, categorization, tabulation, and narrative presentation
Meta-analysis
May be appropriate for sufficiently compatible quantitative evidence
Not normally the purpose of a scoping review
Typical endpoint
An answer or synthesis addressing the review question
An account of what evidence exists, its characteristics, and where uncertainties or gaps may remain
Broad Does Not Automatically Mean Scoping
Researchers sometimes reduce the distinction to a convenient formula: narrow question equals systematic review; broad question equals scoping review. Breadth certainly matters, but this shortcut can be misleading.
A broad field may contain a specific question suitable for systematic review. Conversely, a relatively bounded topic may warrant a scoping review if the purpose is to catalog definitions, methods, measures, or types of evidence rather than estimate or synthesize a particular outcome.
Ask what the review is supposed to produce. "What interventions have researchers studied?" is fundamentally different from "Does this intervention improve this outcome?" even if both concern the same topic.
Scoping Does Not Mean Informal
The word scoping can give the mistaken impression that researchers simply browse the literature before doing the "real" review. A properly conducted scoping review is itself an evidence-synthesis methodology.
Under JBI methodology, scoping reviews begin with an a priori protocol and explicit inclusion criteria related to the review question. They require systematic searching, evidence selection, data charting, and transparent presentation of results. PRISMA-ScR provides a dedicated reporting framework for scoping reviews.
The flexibility lies in what the review seeks to characterize, not in abandoning methodological transparency.
Critical Appraisal Serves Different Purposes
In many systematic reviews, evaluating the methodological quality or risk of bias of included studies is important because the review is making claims based on what those studies found. If the underlying evidence has serious limitations, that should affect how confidently the synthesized findings are interpreted.
Scoping reviews often have a different objective. If the question is simply what kinds of research have been conducted or how a concept has been defined, formal critical appraisal may not be necessary to answer it. PRISMA-ScR therefore treats critical appraisal as something that should be reported when it is done rather than assuming that every scoping review must perform it.
This does not mean that appraisal is prohibited in scoping reviews. The decision should follow the review objective and methodology.
Scoping Reviews Can Help Determine Whether a Systematic Review Is Worth Doing
Suppose a new research area appears to contain studies of several interventions, populations, outcomes, and designs. You are considering a systematic review but do not yet know whether there is a sufficiently coherent body of evidence for a focused synthesis.
A scoping review can characterize that landscape. It might reveal a cluster of sufficiently comparable studies that justifies a subsequent systematic review. Alternatively, it may show that the literature is sparse, methodologically fragmented, or concerned with questions different from the one you hoped to answer.
That does not make every scoping review a preliminary systematic review. Many scoping reviews have useful standalone objectives. It simply illustrates one reason researchers may choose the approach.
Neither Review Type Automatically Requires Meta-Analysis
A systematic review does not have to contain a meta-analysis. Statistical pooling is appropriate only when the available quantitative evidence can meaningfully be combined. The distinction between systematic review and meta-analysis is important because the former is a review methodology while the latter is a statistical synthesis technique.
Scoping reviews generally do not aim to produce pooled effect estimates. If your main objective is to estimate an overall quantitative effect, a scoping review is unlikely to be the appropriate endpoint.
The Reporting Guidelines Are Different
PRISMA 2020 provides reporting guidance primarily for systematic reviews, while PRISMA-ScR was developed specifically for scoping reviews. PRISMA-ScR contains 20 essential and two optional reporting items.
These guidelines concern reporting. They should not be treated as substitutes for methodological guidance on how the review itself should be designed and conducted.
Watch Out
Do not choose a scoping review simply because your question is currently too vague to conduct a systematic review. A scoping review still needs a defensible objective and question. "I do not know what I am looking for yet" is not, by itself, a review methodology.
06 · What This Means for You
Start With the Review Objective, Not the Label
Write down the sentence you hope to be able to complete when the review is finished. The verb often reveals what kind of synthesis you actually need.
A simple decision framework
If you want to determine what the evidence says about a clearly defined question
Consider a systematic review and select the specific systematic review methodology appropriate to that question.
If you want to identify what evidence exists and characterize its breadth, types, concepts, methods, populations, or contexts
A scoping review is likely to fit the objective better.
If you want to estimate a pooled quantitative effect
Plan a systematic review and determine later whether the included evidence is suitable for meta-analysis.
If you want to determine whether enough appropriate evidence exists for a subsequent focused systematic review
A scoping review may be useful.
If your objective is broad conceptual interpretation rather than systematic evidence mapping
Once you have selected the approach, write the protocol before the major review decisions have already been made. If the project will be publicly registered, also determine whether and where the systematic or scoping review should be preregistered .
07 · A Quick Checklist
Before Choosing Systematic or Scoping Review
Before finalizing the methodology, check:
State what the completed review is intended to establish, characterize, or explain.
Determine whether you need an answer to a defined question or a map of the available evidence.
Define eligibility criteria that correspond directly to the review objective.
Choose an appropriate question framework, such as PICO when suitable for a systematic intervention question or PCC when suitable for a scoping review.
Determine whether critical appraisal is necessary for the claims you intend to make.
Plan the protocol before screening and synthesis decisions accumulate.
Use reporting guidance appropriate to the review type, such as PRISMA 2020 or PRISMA-ScR as applicable.
Confirm that your chosen review label accurately reflects the question, methods, and intended conclusions.
09 · The Bottom Line
Ask Whether You Need an Answer or a Map
The Bottom Line
Choose a systematic review when you need to answer a defined question through systematic identification and synthesis of relevant evidence; choose a scoping review when your primary objective is to map, characterize, or clarify the available evidence and its scope.
Both approaches require methodological discipline. Rather than treating scoping review as the easier option or systematic review as the inherently superior one, align the question, eligibility criteria, search, analysis, and reporting with what you actually need the review to accomplish.
11 · Cite this Guide
How to Cite This Guide
This guide is intended to be read, shared, and used in research, teaching, and academic work. If you draw on its ideas, explanations, or other content, please acknowledge the source by citing the guide. Doing so gives appropriate credit and helps your readers locate the original resource.
Recommended (Field Guide)
APA
MLA
Chicago
Copy Citation
