Extended Essay Criterion C: Analysis and Line of Argument
By Michael Thompson · Education Specialist; 10 years teaching the IB at Bromsgrove School · Published 4 October 2026
Extended essay criterion C - Analysis and line of argument - is one of five criteria used to assess the new extended essay from May 2027, and it carries 6 of the 30 available marks. Its guiding question, set by the IB, is: 'Does the student analyse the information presented in the essay and produce a line of argument?' That single question reveals exactly what examiners are looking for: not a summary of sources, but a thread of reasoning that runs from your research question through your findings to your conclusions. Get this right and you also lay the groundwork for criterion D, Discussion and evaluation, which is the most heavily weighted criterion at 8 marks.
Key Takeaways
- Criterion C is worth 6 marks: Under the new 30-mark model (first assessment May 2027), analysis and line of argument sits alongside four other criteria: Framework for the essay, Knowledge and understanding, Discussion and evaluation, and Reflection.
- Analysis is not description: Describing what a source says is not enough on its own; you need to interpret what the evidence means in relation to your research question and explain why it matters.
- A line of argument links three things: According to the IB subject brief, a clear line of argument connects your research question, your research findings, and your conclusions - it should be traceable across the whole essay, not just the conclusion.
- Criterion C and D were once one criterion: The old model's Criterion C 'Critical thinking' (12 marks) has been split: analysis and line of argument now sits in Criterion C (6 marks), while evaluation of findings sits in Criterion D (8 marks).
- No grade boundaries exist yet: The IB will set grade boundaries for the 30-mark scale after the May 2027 session; results are expected 6 July 2027.
- Criterion C connects directly to Criterion A: Your analysis must be grounded in the research methods you identified under Framework for the essay (Criterion A), so weak methodology in Criterion A weakens Criterion C by default.
In This Article
- What Criterion C actually assesses
- How the new extended essay marking criteria changed
- Analysis vs description: the core distinction for extended essay evaluation criteria
- What a strong line of argument looks like across an extended essay
- Common ways drafts fall short on extended essay grading criteria for Criterion C
- Self-check questions for your draft
- How Criterion C connects to the other extended essay criteria
- What to do this week
1. What Criterion C actually assesses
Extended essay criterion C is titled "Analysis and line of argument" and carries 6 marks out of a total of 30. Its guiding question, as published in the IB subject brief, is: "Does the student analyse the information presented in the essay and produce a line of argument?"
The criterion sits third in a five-criterion structure that applies to every extended essay submitted from the May 2027 session onward, following the new model launched in February 2025. The criteria are labelled A to E:
| Label | Criterion name | Marks |
|---|---|---|
| A | Framework for the essay | 6 |
| B | Knowledge and understanding | 6 |
| C | Analysis and line of argument | 6 |
| D | Discussion and evaluation | 8 |
| E | Reflection | 4 |
| Total | 30 |
Two assessment objectives from the subject brief feed directly into this criterion. First, students must apply relevant research methods to respond to the research question and analyse the research to determine appropriate findings. Second, they must develop a clear line of argument that links the research question, research findings, and conclusions. Notice that the second objective spans the whole essay: a strong line of argument is not a paragraph you add near the end, it is a thread running from introduction to conclusion.
One practical point worth knowing: the full mark-band descriptors for Criterion C appear only in the EE subject guide, held on the IB Programme Resource Centre behind a school login. The publicly available subject brief gives criterion names and guiding questions, but not mark allocations or level descriptors; the marks are listed on the IB's extended essay updates page. Ask your supervisor to share the relevant pages of the subject guide before you begin revising your draft against this criterion.
2. How the new extended essay marking criteria changed
Context note: This section is a reference comparison. If you are sitting May 2027 or later, the 30-mark model is the one that applies to you. November 2026 is the last session marked on the previous 34-mark model.
The single biggest structural change is what happened to the old Criterion C, 'Critical thinking', which was worth 12 marks and the highest-weighted criterion in the previous model. The IB did not simply rename it. As Hachette Learning sets out, it was split into two separate criteria:
| New criterion | Marks | What it replaces |
|---|---|---|
| C: Analysis and line of argument | 6 | Part of old Criterion C 'Critical thinking' (12 marks) |
| D: Discussion and evaluation | 8 | Part of old Criterion C 'Critical thinking' (12 marks) |
Two other criteria also changed significantly:
- Old Criterion D 'Presentation' (4 marks) has been absorbed into new Criterion A 'Framework for the essay', where structural conventions now sit alongside the research question and methods.
- Old Criterion E 'Engagement' (6 marks) was based on three written reflections on the Reflections on Planning and Progress Form (RPPF). The new Criterion E 'Reflection' is worth 4 marks and requires one reflective statement, written after the viva voce, on the Reflection and Progress Form (RPF).
The practical consequence of splitting the old 'Critical thinking' block is that building an argument and judging your findings are now assessed as two distinct intellectual moves, each marked independently. Under the old model, a student who wrote strong analysis but thin evaluation could still score well on a single criterion. Under the new model, each skill earns its own mark, so thin evaluation can no longer hide behind strong analysis.
3. Analysis vs description: the core distinction for extended essay evaluation criteria
The simplest way to understand what extended essay evaluation criteria demand of Criterion C is to contrast two sentences covering the same fact.
Descriptive sentence (written for this guide): "Source X found that consumer spending fell by 12% during the period studied."
Analytical sentence (written for this guide): "Source X's finding that consumer spending fell by 12% during the period studied suggests that households prioritised debt repayment over discretionary purchases, a pattern that directly supports the essay's central claim that fiscal tightening suppresses short-term demand."
The descriptive sentence reports what happened. The analytical sentence does three additional things: it interprets the finding, explains the mechanism behind it, and connects it to the research question. That connection is the engine of Criterion C.
Description is not wrong in itself. You need to report what your sources show before you can interpret them. The problem is stopping there. An essay that moves from source to source summarising each one is, structurally, a literature review, not an argument.
What "line of argument" means structurally
A line of argument is not a list of observations arranged in a sensible order. It has a specific architecture:
- Introduction: a position is stated, not just a topic introduced.
- Body sections: each section adds a piece of evidence and reasoning that moves the position forward; no section is self-contained or disconnected from the others.
- Conclusion: the endpoint is arrived at logically from what preceded it, not announced as a separate summary.
The IB EE subject brief frames this as an assessment objective: students must "develop a clear line of argument that links the research question, research findings, and conclusions." Notice the three-part chain. If your conclusion could have been written before you ran your research, the chain is broken.
One practical test: read only your topic sentences. Do they form a coherent, cumulative case? If they read as independent observations, your sections are descriptive units rather than stages in an argument.
4. What a strong line of argument looks like across an extended essay
A line of argument is not a summary of what you found. It is a thread that runs from your research question through every stage of the essay, so that your conclusion feels earned rather than declared. The IB subject brief frames this precisely: one of the core assessment objectives is to "develop a clear line of argument that links the research question, research findings, and conclusions." Each of the essay's three structural parts has a distinct job in making that thread visible.
Introduction. The research question should do more than announce a topic. A well-framed introduction signals the analytical approach - the kind of reasoning the reader is about to follow. If your question is comparative, the introduction should indicate the basis of comparison. If it is causal, it should flag the variables under examination. A reader who finishes your introduction should be able to predict, at least roughly, the shape of the argument ahead.
Body. Each section or paragraph must advance the argument, not simply add more material. Evidence is introduced, then interpreted in relation to the research question, then connected forward or backward to adjacent sections. Transitions between sections carry logical weight - they show why the argument moves where it does, not just that it moves.
Conclusion. The conclusion should arrive at its position because of the analysis in the body. If you could swap your conclusion for a different one without changing the body, the line of argument has not done its job. Traceability - from research question to findings to conclusion - is exactly what the subject brief means by linking those three elements.
One constraint worth noting early: because Criterion C sits downstream of Criterion A (Framework for the essay), the analytical options available to you are shaped by the research methods you justified in your framework. Students who chose methods loosely or without clear justification in Criterion A find their analytical range narrowed here, because the analysis can only work with what their chosen methods produced.
The entire argument must fit within the 4,000-word limit covering introduction, body, conclusion, and any quotations. Every sentence that describes without interpreting is a sentence that weakens the line of argument and costs word count simultaneously.
5. Common ways drafts fall short on extended essay grading criteria for Criterion C
Five weaknesses appear repeatedly in drafts that struggle on this criterion. Recognising them in your own work is the first step to fixing them.
Descriptive drift is the most widespread problem. Entire paragraphs summarise a source or narrate a sequence of events without saying what that information means for the research question. The evidence is present; the interpretation is absent. Under the revised framework, analysis now has a dedicated criterion with its own guiding question, so description that never turns into interpretation is costly.
Disconnected sections produce an essay that reads as a series of independent mini-reports. Each body section presents evidence, but the argument does not accumulate across them. By the final paragraph, the reader cannot trace a logical chain from the research question through to the conclusion, because no such chain was ever built.
Argument stated only in the conclusion. A position that appears for the first time in the final paragraphs leaves the body without a traceable line of argument. Examiners can only credit analysis that is actually on the page, so an argument that surfaces only at the end leaves the body without one.
Conflating analysis with evaluation. This is the counter-intuitive trap introduced by the 2027 revision. Because the old 12-mark Critical thinking criterion is now split across Criterion C (Analysis and line of argument, 6 marks) and Criterion D (Discussion and evaluation, 8 marks), as Hachette Learning sets out, a draft that uses Criterion C territory to weigh limitations and compare interpretations may score well on Criterion D but leave Criterion C thin. The skills are now assessed separately, so evaluation woven through the body still needs clear analysis alongside it.
Research question drift. The argument answers a subtly different question from the one stated at the start. This typically happens when the essay evolves during drafting and the research question is never realigned. The result is a mismatch the examiner will notice even if the student does not.
Read your draft's body sections back to back and ask whether a reader who skipped the introduction could reconstruct the research question from the argument alone. If they could not, at least one of these five problems is present.
6. Self-check questions for your draft
The IB's guiding question for this criterion is: "Does the student analyse the information presented in the essay and produce a line of argument?" The self-check questions below are written for this guide to help you test your draft against that standard and the linked assessment objectives.
Analysis and interpretation
- Can I underline one sentence in each body paragraph that directly interprets evidence in relation to my research question? If no such sentence exists, the paragraph is descriptive, not analytical.
- Have I confused what the evidence means (analysis) with what the evidence says (description)? Read a paragraph back and ask which one you have actually written.
Line of argument
- Does each section advance the argument, or does it introduce an observation that floats free of the surrounding logic? Disconnected observations signal a list of findings rather than a sustained argument.
- Can I trace the logical steps from my research question through my findings to my conclusion without any gaps? A gap at any point breaks the chain the assessment objective requires: a clear line of argument linking research question, findings, and conclusions.
The 2027 model split (a non-obvious check)
- When you weigh a limitation or the significance of a finding (Criterion D territory, worth 8 marks), does each body paragraph still carry its own interpretation that moves the argument forward? Evaluation belongs throughout the essay, but it cannot stand in for the analysis Criterion C is looking for.
Practical reading test (written for this guide)
Read only the first and last sentence of each body paragraph in sequence. If those sentences form a coherent logical chain on their own, the line of argument is likely clear. If they read as a random sequence of observations, the middle of those paragraphs is probably carrying the argument instead of the structure.
7. How Criterion C connects to the other extended essay criteria
The five criteria are not five separate boxes to fill. They are five lenses on the same piece of research writing, and the mark you earn in Criterion C is bound up with the work you do for the others.
Criterion A - Framework for the essay (6 marks). The IB's guiding question for Criterion A asks whether the research question, methods, and structural conventions provide an effective framework. The analytical toolkit available to you in Criterion C is largely determined here. If your chosen research methods are too narrow or poorly matched to the question, the analysis cannot go deep, because there is nothing robust to analyse.
Criterion B - Knowledge and understanding (6 marks). Analysis depends on accurate knowledge. Misread a concept or misuse subject terminology and your interpretation of evidence weakens, regardless of how well-structured your argument looks on the surface.
Criterion D - Discussion and evaluation (8 marks). This is the most heavily weighted criterion in the 30-mark model. Criterion C builds the argument; Criterion D then evaluates what that argument means, weighs the evidence, and acknowledges limitations. They do different work, so make sure each is visibly present rather than letting evaluation stand in for analysis.
Criterion E - Reflection (4 marks). The guiding question asks how the EE learning experience affected you as a learner. Strong reflection also shows awareness of how your analytical choices shaped your conclusions, a metacognitive thread that connects directly back to Criterion C.
The counter-intuitive point: chasing each criterion in isolation tends to produce a fragmented essay. A genuinely strong line of argument, the core of Criterion C, makes the whole essay more coherent, which raises performance across several criteria at once.
8. What to do this week
The full mark-band descriptors for Criterion C sit in the Extended Essay subject guide on the IB Programme Resource Centre, not in the publicly available subject brief. The brief gives you the criterion name and the guiding question; the six-mark allocation is on the IB's extended essay updates page. The guide gives you the level-by-level language examiners actually use when they score your work. Those are two different documents, and only your school has access to the second one.
This week, ask your supervisor to share the Criterion C descriptors from the subject guide. Read each band carefully and identify which descriptor best matches your current draft. Pay particular attention to how the language shifts between bands, because those shifts show exactly what separates the upper mark bands from the middle ones.
No marked example essays exist under the new assessment criteria yet, as the first session is in May 2027. The descriptors in the guide are currently the clearest benchmark available. Contact your supervisor and request them before your next draft session.
FAQ
What is extended essay Criterion C in the new IB model?
Criterion C is titled 'Analysis and line of argument', is worth 6 marks out of 30, and asks whether the student analyses the information presented in the essay and produces a line of argument - first assessed in May 2027.
Can the extended essay criteria change after I start my essay?
The new five-criterion, 30-mark model applies to every student sitting May 2027 or later; the previous 34-mark model is used for the last time in November 2026, so students beginning under the new guide will be assessed on the new criteria throughout.
Does Criterion C count toward my IB diploma points?
Criterion C contributes to the extended essay total mark, which only affects diploma points in combination with Theory of Knowledge - the combined maximum across both components is 3 diploma points.
What is the difference between Criterion C and Criterion D in the extended essay?
Criterion C (6 marks) assesses whether the student analyses information and builds a line of argument; Criterion D (8 marks, the most heavily weighted criterion) assesses whether the student discusses findings and evaluates the essay - skills that the previous model assessed together under a single 12-mark 'Critical thinking' criterion.
When will grade boundaries for the new extended essay be published?
The IB has not set grade boundaries for the new 30-mark extended essay; they will be established after the May 2027 session, with results expected on 6 July 2027.
Where can I find the full Criterion C mark-band descriptors?
The detailed level descriptors are in the extended essay subject guide hosted on the IB Programme Resource Centre, which is password-protected and accessible through your school's IB credentials - the publicly available subject brief lists only criterion names and guiding questions.
References
- Diploma Programme Subject Brief: Extended essay, first assessment 2027 (International Baccalaureate Organization, 2024) - https://www.ibo.org/globalassets/new-structure/university-admission/pdfs/ee_subjectbrief_en.pdf
- DP extended essay updates - International Baccalaureate - https://www.ibo.org/university-admission/latest-curriculum-updates/dp-extended-essay-updates/
- New guide for the IB Extended Essay - Hachette Learning (Joseph Koszary, 2025) - https://www.hachettelearning.com/blog/new-guide-for-the-ib-extended-essay