The essential foundation
Understanding the research
Evidence synthesis requires transparent methods that another researcher could reproduce. The page structure follows the stages students and research teams encounter from question formulation through protocol development, searching, screening, appraisal, synthesis and final reporting.
Evidence synthesis encompasses different review purposes. An effectiveness question might call for a systematic review, while an exploratory field may be better served by a scoping review. A synthesis plan must explain the intended type of claim before prescribing search and analysis steps.
A decision specific to this project
Design selection
Start by deciding whether the aim is to map a field, explain experiences or estimate an effect. The method follows that purpose.
What to prepare
A comparison of review designs, evidence sources and the kinds of conclusions each permits.
Methodological boundary: Do not label a narrative summary a systematic review without the requisite review methods.
Where difficulties begin
Choosing the Right Evidence Synthesis Approach
My PICO question is not specific enough.
My search retrieves thousands of irrelevant records.
I do not know which appraisal tool fits my included studies.
I am unsure whether meta-analysis is appropriate.
I need to structure the PRISMA flow and methods section correctly.
A practical approach
Matching the Question to the Review Design
Determine whether the aim is to assess an intervention, explore experiences, map a field or combine quantitative findings. Consider eligibility principles, search coverage, appraisal needs and relevant reporting guidance for each design.
Identify the kind of evidence question
Determine whether the aim is to assess an intervention, explore experiences, map a field or combine quantitative findings.
Compare synthesis designs
Consider eligibility principles, search coverage, appraisal needs and relevant reporting guidance for each design.
Plan extraction and synthesis
Specify which information answers the question and how differences between studies will be handled.
Set reporting boundaries
Explain what the available evidence can support and what uncertainty remains.
Putting the ideas into context
Comparing Evidence Synthesis Options
A researcher examining digital nursing interventions may need to decide whether the goal is to map available technologies or estimate their impact on a defined clinical outcome. These questions lead to different review methods.
Illustrative example only; check your programme requirements, actual evidence and any necessary permissions.
What support looks like for this topic
How we support your research
Systematic Reviews
Protocol-to-manuscript support organised around a reproducible review question and transparent reporting.
Scoping Reviews
Map the breadth, characteristics and gaps within a body of evidence using a clearly defined review framework.
Meta-Analysis
Support with effect measures, model choice, heterogeneity, sensitivity analysis and interpretation of pooled findings.
Search Strategy
Translate the review question into concepts, controlled vocabulary and database-specific search strings.
Screening & Data Extraction
Build eligibility criteria, screening logic and structured extraction fields that align with the review question.
Critical Appraisal & Risk of Bias
Select and apply appraisal tools appropriate to the included study designs.
Good research practice
A practical note for this stage
We can help you work through the decisions involved in screening, synthesis and reporting, using your research question and programme expectations as the starting point.
Explore the subject further
Related specialist areas
Focused guidance for the next decision in your research.
Question formulation, protocol, searching, screening, appraisal, synthesis and PRISMA reporting.
Map the breadth of evidence, concepts, study characteristics and research gaps.
Effect sizes, pooling, heterogeneity, sensitivity analysis, forest plots and interpretation.
PICO concepts, keywords, controlled vocabulary and searches across CINAHL, PubMed and other databases.
Eligibility criteria, title/abstract screening, full-text decisions and structured extraction.
JBI, CASP, RoB 2 and other design-appropriate appraisal approaches.
Questions researchers ask
Frequently asked questions
Can I request only one stage of a review?
Yes. The architecture supports modular requests such as search strategy, screening, data extraction, appraisal, synthesis or manuscript support.
Do all systematic reviews need a meta-analysis?
No. Meta-analysis is appropriate only when the included studies are sufficiently compatible and the review question supports quantitative pooling.
Can a scoping review be used instead?
Yes, when the objective is to map the breadth and characteristics of evidence rather than estimate a pooled effect.
Further reading
Research standards and reliable resources
These external resources can help you explore relevant methodological guidance. Always follow the requirements of your programme and verify the version of any standard you use.