Cambridge International AS & A Level History (9489): How to Answer Paper 1(a) Source Comparison Questions
You need to do three things: explain a similarity, explain a difference, and explain why the sources agree or disagree. Every comparison must address the specific issue in the question.
This question is worth 15 marks. You can start directly with a comparison: an introduction is unnecessary. Note that examiners also distinguishes between comparing the content and explaining the reasons behind the comparison.
1. Before writing: identify what you are comparing
Underline the focus of the question.
If it asks about attitudes towards child labour, compare what the authors think about child labour.
If it asks about motives for intervention, compare why the sources suggest intervention happened.
If it asks about responsibility for a war, compare whom the sources blame.
Do not simply find any similarity or difference. Find one that answers the question.
Read both sources fully, including their attributions, before choosing quotations.
2. Use this clear four-paragraph structure
This is a practical structure you can follow, rather than a compulsory Cambridge formula.
Paragraph | What you must do |
1. Explain a similarity | State what the sources agree about. Support it with evidence from both sources and explain the connection. |
2. Explain a difference | State the issue on which they disagree. Support both sides with evidence and explain the contrast. |
3. Explain why they agree | Use relevant context and/or the authors’ circumstances to explain the similarity identified in Paragraph 1. |
4. Explain why they differ | Use relevant context and/or the authors’ circumstances to explain the difference identified in Paragraph 2. |
You can instead attach each explanation directly to its comparison, creating two longer paragraphs. Both structures work; what matters is that the explanation clearly connects to the comparison.
3. Paragraph 1: explain a similarity
Follow these steps:
State the precise agreement.
Give a short quotation or precise reference from the first source.
Explain how it supports your point.
Give matching evidence from the second source.
Explain what both sources therefore agree about.
Sentence framework:
Both sources agree that [specific point relevant to the question]. Source A states [short quotation], suggesting [explain its meaning]. Similarly, Source B states [short quotation], indicating [explain its meaning]. Both therefore present [precise shared view].
Example from a Bismarck answer to the question "To what extent do these two sources agree about Bismarck’s attitude towards France? [15]"
Both sources present Bismarck as wishing to avoid war with France. Source C describes his distress at the human cost of war and his rejection of war for personal ambition. Similarly, in Source D he states that he will do what he can to prevent war. Both therefore present peace as his preferred course.
Why this works: it identifies a shared attitude, supports it from both sources and explains the agreement.
Avoid simply saying:
“Both sources discuss war.”
That identifies a shared topic, not a shared view.
4. Paragraph 2: explain a difference
Compare the sources on the same issue.
Follow these steps:
State the precise contrast.
Support the first source’s position.
Support the second source’s different position.
Explain how they differ.
Sentence framework:
However, the sources differ over [shared issue]. Source A presents [position], shown by [evidence]. In contrast, Source B presents [different position], shown by [evidence]. Therefore, while A suggests [interpretation], B suggests [contrasting interpretation].
Example answer:
However, the sources differ in how firmly Bismarck confronts France. Source C stresses that only vital national interests justify war. Source D ends with a warning that German feelings must be respected and that Bismarck cannot guarantee the response of the king or people. C therefore emphasises restraint, whereas D adopts a more threatening position.
This does not contradict the earlier similarity. Both sources can express a preference for peace while differing over how readily confrontation might become acceptable.
That distinction demonstrates a careful reading of the sources.
5. Paragraph 3: explain why the similarity exists
Now answer a different question:
“Why would these authors express this shared view?”
Possible explanations include:
They share a political objective.
They have experienced the same conditions.
They address audiences with similar concerns.
They have a common interest in presenting events in a particular way.
Sentence framework:
This agreement can be explained by [specific shared context, interest or purpose]. [Explain the relevant circumstances.] This helps explain why both sources emphasise [the similarity already identified].
Bismarck example:
The similarity can be explained by Bismarck’s interest in avoiding responsibility for a future war. Presenting himself as peaceful would help place the blame on France if conflict occurred. This explains why both sources stress his wish to avoid war despite their different degrees of firmness.
Notice the connection:
Shared political interest → shared presentation of his attitude.
Do not merely add facts about German unification. Explain how those facts account for the agreement.
6. Paragraph 4: explain why the difference exists
Ask:
“What changed, or what differed between the authors’ circumstances, that helps explain this contrast?”
Consider:
Developments between the dates of the sources.
Different audiences.
Different aims.
Different experiences or responsibilities.
Sentence framework:
The difference can be explained by [specific contextual development or difference in purpose/audience]. Source A was produced when/for [relevant circumstances], which helps explain its emphasis on [view]. By contrast, Source B was produced when/for [different circumstances], helping explain [contrasting view].
Bismarck example:
The difference can be explained partly by the consolidation of the North German Confederation between the two sources. By September 1867, Bismarck spoke from a stronger political position, helping explain his firmer warning. The audiences also differed: reassuring a German correspondent about war served a different purpose from communicating a warning through a British journalist.
Examiners for this example specifically credits explanations using developments during 1867 and the different purposes and audiences. Both sources are associated with Bismarck, so simply identifying the author cannot explain the difference.
7. Understand the difference between “what” and “why”
This is the most important distinction:
Stage | Question you answer | Example |
Content comparison | What do the sources agree or disagree about? | Both present Bismarck as wanting peace, but D is more threatening. |
Explanation | Why do they present the issue this way? | He wants France blamed for any war, while his stronger position and different audience help explain D’s warning. |
Quotations establish the comparison. Context and source evaluation explain it.
Repeating the comparison in different words does not explain why it exists.
8. What moves an answer into the higher levels?
Level | Marks | Main achievement |
1 | 1–3 | Describes the sources with little developed comparison. |
2 | 4–7 | Identifies similarities or differences, or asserts both without supporting evidence. |
3 | 8–11 | Explains both similarities and differences with supporting source content. |
4 | 12–15 | Develops the comparison by explaining why similarities and differences exist through context and/or source evaluation. |
Cambridge assesses the answer as a whole. Completing four paragraphs does not automatically secure Level 4: the comparisons and explanations must be valid and supported.
9. Do you need an introduction or conclusion?
Introduction: No. Start with your first comparison.
Conclusion: A long conclusion is unnecessary. You may finish with one sentence clarifying the overall relationship:
Overall, the sources agree on Bismarck’s stated preference for peace, but differ in the firmness of his attitude towards France.
Do not spend time repeating every point. Prioritise the supported comparisons and explanations.
10. Avoid these mistakes
“A mentions something that B does not.” Silence alone does not establish disagreement.
“A is a letter; B is an interview.” Explain how the different circumstances shape the views expressed.
“A is biased.” Identify the specific interest or purpose and connect it to the comparison.
Long background paragraphs. Use only context that explains the agreement or disagreement.
Unsupported emotional labels. Acknowledging suffering does not automatically demonstrate sympathy or regret.
Invented purposes. Establish your explanation from the attribution, wording and historical context.
Extra comparisons without explanation. Develop your strongest points before adding weaker ones.
Your final checklist:
Have I identified a clear similarity and difference?
Have I supported each with evidence from both sources?
Have I explained what the evidence means?
Have I explained why the agreement and disagreement exist?
Does every paragraph address the exact focus of the question?
