Synthesize competing evidence into a reasoned judgement
Compare evidence across perspectives, weigh trade-offs against stated criteria and make a conclusion that fits the research.
Section SYNTHESIS-JUDGEMENT · Synthesize competing evidence into a reasoned judgement
Exam scope and assessment notes
This is original StudyForA teaching and fictional practice, not Cambridge text, an official question or an official mark scheme. The 2026–2028 syllabus calls the written exam Component 1; the 2029–2031 syllabus calls it Paper 1 and reports no significant teaching changes. Check the syllabus for the learner's exam year and follow teacher, centre and assessment-authenticity rules. StudyForA cannot authenticate assessed work, observe collaboration, award official marks or predict a grade.
Before you begin
- Identify whether the task concerns source analysis, essay writing, team assessment or the independent research report.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is synthesis?
What you will learn
- Synthesize relevant evidence from contrasting sources
- Weigh arguments using consistent criteria
- Make a supported judgement with appropriate limits
Synthesis connects sources
Synthesis explains how sources agree, differ or address different parts of a question. It is not a sequence of summaries. Compare their methods and contexts, identify which claims are supported and show how the combined evidence bears on the decision.
Make the judgement follow
Choose criteria that matter to the question, such as effectiveness, cost, access or durability. Weigh both benefits and consequences, then state which option is better supported and under what conditions. A qualified judgement can be decisive while acknowledging a genuine evidence gap.
Sources for this lesson
- Cambridge International AS & A Level Global Perspectives & Research 9239 syllabus · 2026–2028 Version 3
- Cambridge International AS & A Level Global Perspectives & Research 9239 syllabus update · 2026–2028
- Cambridge International AS & A Level Global Perspectives & Research 9239 syllabus · 2029–2031 Version 1
- Cambridge International 9239 subject page and exam-series notice
Pause and explain
What should a qualified conclusion do?
Worked example
A school considers a later start time. Attendance improves in one small pilot, but transport costs rise. How should the evidence inform a judgement?
Show the worked solution
- Check the attendance pilot's sample, duration and other changes.
- Compare attendance and cost against a shared set of criteria.
- Recommend only what the evidence supports and identify a condition or further check.
Answer The pilot suggests attendance may improve, but its short duration and small sample limit confidence. Higher transport costs are relevant to feasibility. If attendance is the priority, a longer trial could be justified only if the school can manage cost and monitor access. The current evidence does not establish that every year group would benefit.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A trial of evening buses increases use by 18%, while a budget note warns of higher staffing cost. Write a three-part judgement plan.
Give me a hint
Check the baseline and period, then weigh access and feasibility.
Compare my reasoning
- Check what the 18% compares and who used the buses.
- Compare access benefits with recurring staffing cost.
- State a conditional recommendation and the evidence needed next.
First verify the baseline, comparison period and routes included in the 18% increase. Then weigh whether the added trips improved access for intended users against recurring staffing costs. A conditional recommendation could support a longer trial on the routes with demonstrated need, while tracking passengers, reliability and cost. The figure alone does not show who gained access.
Look for these in your work
- Checks the measure
- Weighs benefits and costs
- Makes a conditional, evidence-based recommendation
Two studies disagree about whether an online service improves access. Give two reasons their results might differ before deciding one is wrong.
Give me a hint
Compare populations, definitions and time periods.
Compare my reasoning
- Compare who took part and where the study took place.
- Check how each study defined and measured access.
- Compare timing, method and other changes.
The studies may include different users or locations, define access differently, or measure different periods. One may count successful logins while another measures whether users completed the service. Check methods and context before weighing the results; disagreement alone does not show that one study is false.
Look for these in your work
- Offers relevant methodological explanations
- Compares definitions or scope
- Avoids premature dismissal
A source strongly supports a policy, but the only reliable data cover one district. Write a conclusion that uses the evidence without generalising it to every district.
Give me a hint
Name the place and state what further evidence would change the scope.
Compare my reasoning
- State the observed result and district.
- Explain what the result supports locally.
- Name what is needed before extending the judgement.
The data support considering the policy in the district studied, where the measured outcome improved under the reported conditions. They do not establish the same effect in all districts. Compare settings with different populations and resources before recommending a wider rollout.
Look for these in your work
- Keeps the conclusion within the sample
- States a useful implication
- Identifies evidence needed for broader claims
Common mistakes
- Counting supporting statements instead of weighing their importance
- Adding a conclusion that does not follow from the analysis
- Hiding uncertainty to make a recommendation sound confident
What can you explain now?
What is synthesis?
Compare with the explanation
Connecting evidence across sources to show how it supports, qualifies or challenges an argument.
Synthesis shows relationships among sources rather than reporting each in isolation.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
What makes a judgement follow from evidence rather than merely repeat an opinion?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.