Complete guide
IB Extended Essay guide
The Extended Essay is a 4,000-word independent research paper that contributes up to 3 bonus points toward your IB Diploma score when combined with TOK. It is marked out of 34 across five criteria. This guide covers how to choose a topic, structure your essay, and understand exactly what each criterion expects.
The 5 assessment criteria
Examiners score each criterion independently. Criterion C (Critical Thinking) is worth the most marks.
| Criterion | Name | Marks |
|---|---|---|
| A | Focus and method | 6 |
| B | Knowledge and understanding | 6 |
| C | Critical thinking | 12 |
| D | Presentation | 4 |
| E | Engagement | 6 |
| Total | 34 | |
Grade boundaries
An E grade in the EE can result in failing the IB Diploma, regardless of other scores.
E
0–6
D
7–13
C
14–20
B
21–27
A
28–34
EE topic ideas by subject
These are starting points — your actual research question must be more specific and scoped to your available resources.
Biology
- Effect of caffeine concentration on Daphnia heart rate
- Antimicrobial properties of common household substances
- Impact of soil pH on root growth in legumes
Chemistry
- Determining the activation energy of the iodine clock reaction
- Comparing vitamin C content across fruit juices using iodometric titration
- Effect of temperature on rate of ester hydrolysis
Physics
- Modelling projectile motion with air resistance
- Investigating how solenoid geometry affects magnetic field strength
- Efficiency of a solar cell under varying light wavelengths
Mathematics
- Modelling the spread of a rumour using logistic growth functions
- Exploring fractal geometry in natural coastlines using the box-counting method
- Investigating Benford's Law in financial datasets
History
- To what extent did economic factors cause the fall of the Weimar Republic?
- How effective was the Allied strategic bombing campaign in undermining German morale 1943–1945?
- To what extent did the Non-Aligned Movement influence Cold War dynamics?
Economics
- To what extent has ride-sharing disrupted the taxi market in [city]?
- How effective has the sugar tax been in reducing obesity in the UK?
- Analysing the impact of minimum wage increases on youth employment in New Zealand
Psychology
- To what extent do social media algorithms reinforce confirmation bias?
- Evaluating the reliability of eyewitness testimony in criminal trials
- How does sleep deprivation affect working memory performance?
English Literature
- How does Kazuo Ishiguro use unreliable narration in 'Never Let Me Go' to explore memory and loss?
- Exploring the treatment of colonial trauma in Chimamanda Ngozi Adichie's 'Half of a Yellow Sun'
Common questions
What is the word limit for the IB Extended Essay?
The strict limit is 4,000 words. Text beyond this point is not assessed. The word count includes all body text — introduction through conclusion — but excludes the title page, table of contents, bibliography, appendices, and figure captions.
Which subject should I write my EE in?
Choose a subject you study (ideally at HL) where you can access primary sources: original data from an experiment, primary texts for literature, raw statistics for economics. Examiners can immediately spot an EE that relies entirely on secondary sources and it is hard to score well on Criterion C (Critical Thinking) without engaging with primary material.
What is the RPPF?
The Reflections on Planning and Progress Form is a 500-word document where you record your thinking across three formal supervisor sessions. It contributes to Criterion E (Engagement, worth 6 marks). Write in first person, describe specific decisions you made and challenges you solved, and be honest about dead ends — authentic reflection scores better than polished narrative.
Can the EE topic overlap with my IA?
Your EE and IA must be distinct pieces of work. You can work in the same broad subject area but the research questions must be different and the work entirely separate. You cannot re-use data, analyses, or sections between them.