Extended Essay research question examples: 33 focused RQs, from Biology to History

A good Extended Essay research question passes three tests: it is focused (one relationship, one case or one text, with limits stated), arguable (the answer requires evidence to be weighed, not just reported) and researchable in 4,000 words with evidence you can actually get. The 33 examples below pass all three. Each comes with the reason it works, so you can borrow the shape, not the topic.

Use them as models, not as topics to lift: the decisions behind your question must be yours, and you will be asked to explain them in the viva.

What makes an EE research question good?

The research question carries much of criterion A and sets the ceiling for the analysis and evaluation criteria; the EE criteria explained shows how. For turning a vague idea into a precise question step by step, see how to write a research question.

Science research question examples

Biology

1. How does sodium chloride concentration (0–200 mmol dm⁻³) affect the germination rate and radicle length of Raphanus sativus seeds over seven days?
   Why it works: one independent variable with a range, two measurable responses, cheap and ethical, and the osmotic-stress literature gives plenty to discuss.
2. To what extent does stomatal density differ between sun-exposed and shaded leaves of Hedera helix at a single named site?
   Why it works: fieldwork plus microscopy (nail-varnish leaf impressions), a clear comparison, and an adaptation argument to evaluate.
3. How does storage time at 4 °C (0–48 hours) affect the inhibition of Bacillus subtilis growth by fresh garlic extract, measured by the diameter of the zone of inhibition?
   Why it works: links a measurable effect to the known instability of garlic's active compounds. It needs your school's approval for microbiology work.
4. How has the first-flowering date of one named species in one country changed with mean spring temperature, using records from a national phenology database (1990–2020)?
   Why it works: a secondary-data EE with a large data set, real statistics and climate-change context, no lab needed.

Chemistry

5. How does heating time at 80 °C (0–60 minutes) affect the ascorbic acid concentration of fresh orange juice, determined by iodometric titration, and does the loss follow first-order kinetics?
   Why it works: the second half turns a measurement into a claim you can test with a ln(concentration) against time graph.
6. How does the concentration of tannin extracted from black tea (0–2.0 g dm⁻³) affect the corrosion rate of mild steel in 1.0 mol dm⁻³ hydrochloric acid, measured by mass loss over 48 hours?
   Why it works: a real research area (plant-based corrosion inhibitors), simple apparatus, and adsorption models to compare the data against.
7. How does pH (3–9) affect the rate of degradation of anthocyanins extracted from red cabbage at 25 °C, measured by the fall in absorbance at each solution's absorbance maximum over 24 hours?
   Why it works: colorimetry gives continuous data, and the pH-dependent structure of the pigment gives the chemistry depth.

Physics

8. How does the drop height (0.20–1.00 m) of a steel ball affect the diameter of the crater it forms in fine dry sand, and does the relationship follow a power law?
   Why it works: the power-law fit on a log–log graph gives an exponent to compare with energy-scaling arguments.
9. How does temperature (20–80 °C) affect the magnetic flux density 2.0 cm from a neodymium magnet, measured with a Hall probe, and is the change reversible on cooling?
   Why it works: two linked questions, both measurable, with a materials-physics explanation to evaluate. Keep below the temperature at which your magnet grade starts to lose magnetisation permanently.
10. Is the damping of a pendulum with a light card bob better modelled by drag proportional to speed or to speed squared, across bob areas of 25–200 cm²?
    Why it works: it sets two models against each other, so the essay has a genuine question to settle with data.

Maths research question examples

11. How often do plurality voting, instant-runoff and the Borda count choose different winners in simulated four-candidate elections, and which most often fails to elect a Condorcet winner?
    Why it works: social choice theory is beyond the course but explainable, and a simulation gives you results to analyse.
12. How much shorter is the Steiner tree than the minimum spanning tree connecting five named towns, and why?
    Why it works: it takes minimum spanning trees (met in Maths AI HL graph theory) into geometry, with a real application and a precise comparison.
13. What is the optimal strategy in the dice game Pig, and how much does it improve the probability of winning against a "hold at 20" strategy?
    Why it works: probability and dynamic programming applied to a clear goal, with a numerical answer to compare against intuition.

Strong maths EEs usually go beyond what the course teaches, but only as far as you can explain clearly enough for a classmate to follow. A question that only applies syllabus techniques to a new context is usually better as an IA (see maths IA topics for that kind).

ESS research question examples

14. How does distance from a footpath (0–10 m) affect species richness and percentage cover of ground vegetation in a named woodland, and what does this suggest for managing trampling?
    Why it works: a repeatable transect method plus a management question, which is what makes it ESS rather than Biology.
15. To what extent does household income explain differences in rooftop solar capacity between the districts of one municipality?
    Why it works: public data, a social and environmental question, and an equity argument to evaluate.
16. How did a change in kerbside food-waste collection frequency affect food waste collected per household in two comparable districts of one city?
    Why it works: a natural experiment with council data, and a systems question about waste management.

Psychology, Economics and Global Politics examples

Psychology

17. To what extent does research support the claim that bilingualism improves executive function in children?
    Why it works: a live debate with studies on both sides, so the essay is about evaluating evidence, including publication bias.
18. How far can the misinformation effect found in laboratory studies explain errors in eyewitness testimony in real criminal cases?
    Why it works: it sets lab evidence against field evidence, so ecological validity becomes the core of the analysis.
19. To what extent can longitudinal studies show that social media use causes depressive symptoms in adolescents?
    Why it works: the question is about what the methods can and cannot show, which is exactly what criterion D rewards.

Economics

20. What does the effect of England's single-use carrier bag charge, introduced in 2015, suggest about the price elasticity of demand for carrier bags?
    Why it works: one policy, published sales data, and one economic concept doing real work.
21. To what extent did the August 2023 expansion of London's Ultra Low Emission Zone reduce the use of non-compliant vehicles in outer London, and who bore the cost?
    Why it works: externality theory, available data and an equity question to weigh.
22. To what extent do petrol prices at the stations along one named road behave as models of oligopoly pricing predict?
    Why it works: your own price data collected over weeks, tested against theory. It is primary research without human participants.

Global Politics

23. How effective was ECOWAS's response to the 2023 coup in Niger in restoring constitutional order, and why?
    Why it works: one organisation, one case and one measure of success, with sovereignty and legitimacy as the concepts.
24. To what extent did the Paris Agreement's nationally determined contributions change one named country's emissions policy between 2015 and 2023?
    Why it works: it tests whether a non-binding commitment changes state behaviour, using official documents.

History and English A examples

History

25. To what extent was the 1936 Berlin Olympics a propaganda success for the Nazi regime, judged by its coverage in the British and American press?
    Why it works: a bounded body of primary sources and a clear criterion for "success".
26. To what extent were economic grievances, rather than political demands, the main cause of the Kronstadt rebellion of March 1921?
    Why it works: two competing explanations, one event, and published primary sources in translation.
27. How significant was the Mothers of the Plaza de Mayo movement in bringing about the end of military rule in Argentina (1977–1983)?
    Why it works: "how significant" forces a comparison with other factors, such as the Falklands defeat and the economy.

English A

28. How does Kazuo Ishiguro use Stevens's unreliable first-person narration in The Remains of the Day to expose the cost of professional loyalty?
    Why it works: one text, one technique and one effect, which keeps it analytical rather than descriptive.
29. In what ways does the fragmented chronology of Toni Morrison's Beloved mirror the workings of traumatic memory?
    Why it works: it links structure to meaning, and the claim can be tested passage by passage.
30. How do two UK newspapers with opposing editorial lines use lexical choice and images to frame small-boat Channel crossings on their front pages over one month?
    Why it works: a defined corpus of non-literary texts and a clear comparison for a Language and Literature student.

Language A essays no longer have the old categories, so a single text, two texts or a non-literary corpus can all work if the question is tight.

Interdisciplinary research question examples

The interdisciplinary pathway integrates two DP subjects, and each essay is registered under one of five frameworks (shown in brackets below). The rules on which subjects and languages are allowed are in which subject to choose for your EE.

31. Biology and Economics (sustainability, development and change): To what extent can the economic value of pollination by wild bees justify subsidising flower-strip margins on arable farms in one named region?
    Why it works: the ecology produces the evidence and the economics produces the judgement; neither subject could answer it alone.
32. History and Chemistry (evidence, measurement and innovation): How far did the Haber–Bosch process allow Germany to sustain its war effort after the Allied blockade cut off imports of Chilean nitrate?
    Why it works: the chemistry of ammonia synthesis and nitrate production supports a historical argument about the length of the war.
33. Psychology and English A (culture, identity and expression): How accurately does Pat Barker's Regeneration represent the effects and treatment of shell shock, judged against current psychological understanding of post-traumatic stress?
    Why it works: a literary reading and a psychological evaluation meet in one judgement about accuracy.

Weak to strong: five rewrites

Ethics and feasibility checks before you commit

• People. Surveys, interviews and experiments need informed consent, the right to withdraw, anonymity and no harm. Under-18 participants usually need parental consent, and your school may need to approve anything run in school. Psychology essays often rest on published studies for this reason.
• Animals. Experiments involving animals are tightly restricted; check the IB's guidance with your supervisor before planning any.
• Safety. Microbiology, heat, acids and electricity need a risk assessment and supervision. Your supervisor has to sign off on ethics and safety.
• Access. Check before you commit that the data set exists, the archive is open or digitised, the text is available in a language you can read closely, or the equipment is free when you need it.
• Time. If data collection needs a season (flowering, migration, a field trip), the question has to be fixed before that season starts.
• Recency. Very recent events can be short of scholarly sources. Check your subject's guidance on how recent a topic can be.

Still deciding which subject to write in? Read which subject to choose for your EE, then the full Extended Essay guide for the timeline.