Maths IA criteria · 3 marks
Criterion C: Personal engagement
Personal engagement is the most misunderstood criterion. It is not about how hard you worked or how much you love the topic. It is about evidence, throughout the exploration, that you made the mathematics your own. It is worth 3 marks.
What Criterion C assesses
The extent to which you engage with the exploration and make it your own — independent thinking, creativity, and a personal approach to the mathematics — shown in the work itself, not claimed in the introduction.
This is our summary, not the IB's wording. The descriptors themselves, with a checklist and a self-grade sheet, are on the IA criteria page.
What the mark bands look like in practice
| Band | What the examiner typically sees |
|---|---|
| Low (1) | Engagement is limited or superficial: a personal reason in the introduction, then a standard textbook-style exploration. |
| Middle (2) | Some genuine engagement: the student makes some of their own choices, but much of the work follows a well-known path. |
| Top (3) | Significant engagement that drives the exploration: the student's own questions, predictions, data and decisions shape what happens next, on many occasions. |
Checklist for Criterion C
- Your own question — not a topic lifted from a list without changes.
- Predictions made before calculating, then tested (“I expected the exponential to fit better because…”).
- Questions you ask and answer along the way (“Would this still work for a deeper chain?”).
- Your own data or measurements where possible, and your own decisions about how to collect them.
- Decisions explained: why this model, why this method, why not the obvious alternative.
- Mathematics that is unfamiliar to you, clearly explained in your own words (and said to be new to you).
- Different perspectives: comparing methods, historical or global context used mathematically.
- Your own presentation of the results — your graphs, your tables, your explanations.
Examiner tips
Show, don't tell.
“I have always loved football” earns nothing on its own. Choosing to test your own penalty data, predicting the result, and explaining why your prediction was wrong is personal engagement.
Avoid the textbook route.
If your exploration could be a worked example in a textbook, it will struggle here. Change the question, the data or the method until it is recognisably yours.
Engagement is not effort.
Examiners mark the evidence on the page. Twenty hours of work that reads like a report of a standard method can still score low; a modest exploration full of your own decisions can score full marks.
Weak vs strong: an example
Loses marks
“I chose this topic because I am interested in basketball. Next, I will calculate the correlation coefficient.”
Earns marks
“Before calculating r, I predicted a weak correlation, because in my own team the tallest player is not our best shooter. The value r ≈ 0.12 supports this, but it made me wonder whether distance from the basket is the real variable — so I recorded where each shot was taken from.”
Common Criterion C mistakes
- Personal engagement only in the first paragraph.
- Choosing a topic from a list and following a published approach step by step.
- Reporting what you did without ever explaining why.
- Using data from a single website with no decisions about how to clean or select it.
Frequently asked questions
Does personal engagement mean writing about myself?
No. A personal reason for choosing the topic is fine, but the marks come from evidence of your own thinking throughout the mathematics: predictions, questions, decisions and your own approach.
Can a pure maths IA score well on personal engagement?
Yes. Exploring small cases yourself, making conjectures, trying approaches that fail and explaining what you learned is strong personal engagement even with no real-world context.
Does collecting my own data guarantee full marks for C?
No — it helps, but what matters is what you do with it: the decisions you make, the questions you ask, and how the data shapes your exploration.