IB Math Internal Assessment Explained
What the five criteria require, where students consistently underperform, and why most struggle on their IB Math IA without experienced guidance.
I have guided students through the IB Math Internal Assessment across all four courses. Most students can read the criteria. The difficult part is knowing what those criteria actually require in their own writing.
What Is the IB Math Internal Assessment?
The IB Math Internal Assessment is an individual mathematical exploration worth 20% of your final grade. You choose a topic, investigate it, and present it in a written report of 12 to 20 pages.
There are no past papers for it. No timed conditions. No fixed method. You choose the topic, the approach and the structure, and every one of those choices is marked.
It is assessed against five criteria set by the IB, out of 20 marks. Reading those criteria takes ten minutes. Applying them to your own work is where it comes apart, because the descriptors were written for the people marking your IA, not for the student trying to satisfy them.
The mark you are given is not the mark you keep
Your IA is marked in your school, then sent to the IB. There, a sample of the school’s work is reviewed by an external moderator. If the difference between the school’s marking and the moderator’s marking falls outside the expected tolerance for the assessment, the school’s marks can be adjusted.
I have read hundreds of IAs across all four courses. I know what the criteria look like in a real exploration, and why strong mathematics is often not enough on its own. I give you clear, experienced feedback on your own work so you know what needs attention and can act on it, while the writing and decisions remain yours.
What Each Criterion Rewards
Five criteria, twenty marks. The descriptors are short and they sound reasonable. Here is what each one actually rewards, and the place I most often watch students underperform.
Presentation
Coherent and well organised earns you the 3. Concise earns the 4. That single word is the whole top band, and it is the mark I see missed most often.
Where it goes. The Wikipedia Introduction, two to four pages of history before any mathematics appears. The Page Filler, where removing a graph would cost the argument nothing. The Calculator Dump, every GDC screenshot pasted in as proof of effort. The Labeled-but-Unreferenced Graph, numbered, captioned, and never once pointed to in the text.
How it is marked. Conciseness is judged by a reader who did not do the work. No page is given the benefit of the doubt.
Mathematical Communication
Correct notation most of the time is not the standard. Every time is.
Where it goes. The Notation Neglect. Function notation in one section and y equals in the next. Variables used before they are defined. I have read explorations correct on every line where the fourth mark still goes, lost to small slips. A missing degree symbol. A point label used twice. A value written 88.789 on one line and 88.798 on the next.
How it is marked. The person marking your IA reads only what is on the page. Nothing you meant but did not write can be credited.
Personal Engagement
This mark is not for a heartfelt introduction. It is the criterion students are most certain they have earned, and most often have not.
Where it goes. The Criterion C Confusion, where a student explains on page one why they love the topic and then follows textbook method mechanically for nine pages. Engagement that appears once and never returns scores a 1, however genuine it was.
How it is marked. This criterion measures engagement with the mathematics, not enthusiasm for the subject. I have records of an exploration with full marks for presentation and notation, and correct statistics throughout, held to 16 out of 20 by engagement alone. Nothing was wrong with it. Something was missing from it.
Reflection
Describing what you did is not reflection, however carefully you write it. Evaluating what your results mean, why your approach is limited, and what that does to your conclusion is.
Where it goes. The Reflection Afterthought, quarantined in the last two pages while the body reports result after result without comment. The Superficial Limitation, “my sample size could be larger,” lines that would fit any IA ever written. Then the costliest, the Meaningful-not-Critical Ceiling, real reflection that still stops at 2 out of 3 because every sentence describes or interprets and none evaluates.
How it is marked. This criterion turns on a single line, whether a sentence describes or evaluates. That line decides more marks here than anything else in the IA.
Use of Mathematics
Six marks, the most of any criterion, and the one where strong mathematicians are most exposed. Correct mathematics sits in the middle of this scale, not at the top. The upper bands need demonstrated understanding, and at HL sophistication and rigour on top of it.
Here is the part almost nobody outside the marking is told. I have watched the same above-level mathematics, correct on every line, land on five different marks at HL depending only on how it was deployed.
Same mathematics. Five outcomes. The difference is never difficulty.
Where it goes. Two more routes down. The Outsourced Computation, where the integral is a number GeoGebra returned and the technique the whole IA is built on is never performed on the page. And the Level Drop, an HL exploration built on SL-depth work. I have explorations that score 6 at SL and 4 at HL on identical mathematics, because HL asks for sophistication and rigour as well. HL students cap themselves here quietly, while the topic sounds advanced enough that nobody questions it.
How it is marked. Correct mathematics is not the same as demonstrated understanding, and at HL it is not the same as sophistication or rigour. That distinction is the whole criterion.
The patterns I see again and again
Criterion E is worth the most marks, and plenty of students struggle there. But moving from a 13 to an 18 almost always comes down to B, C, and D, how the mathematics is explained, reflected on, and presented, not whether it is correct.
None of these are mathematics problems. Every one of them was written by a student who believed that section was finished.
Common Questions
What students ask most about the IB Math Internal Assessment.
The IB recommends 12 to 20 pages, double spaced, excluding the bibliography and appendix. But length is not the standard, conciseness is. A focused 14-page exploration will beat a padded 22-page one, because Criterion A rewards work in which every page earns its place. I have seen long IAs score at the top. None of them were long by accident.
Your teacher marks it against the five criteria: Presentation (4), Mathematical Communication (4), Personal Engagement (3), Reflection (3) and Use of Mathematics (6). That is 20 marks, worth 20% of your final grade. The IB then externally moderates a sample of your school’s work to check the criteria were applied as intended, and can adjust the school’s marks. Your teacher’s mark is not automatically the mark you keep.
Because a topic can be entirely correct and still cap your score before you have written a line. Some topics can only be described rather than explored, so reflection has nothing to attach itself to. Some are too broad to develop inside 12 to 20 pages, so every method stays shallow. Some sound advanced and only ever permit SL-depth work. The difficulty is that a capped topic looks completely fine to the student who chose it. That is what makes it expensive to discover in March.
The five criteria and the mark totals are identical. The difference is Criterion E. SL asks for thorough knowledge and understanding of mathematics at the level of the course. HL asks for sophistication and rigour as well. In practice, identical mathematics can score 6 at SL and 4 at HL, and I have explorations in my records where exactly that happened. HL students are the ones who most often do not know which of those two they have written.
Technically yes, and it carries real risk. Criterion C rewards engagement with the mathematics, not with the topic. If your approach, structure, and reasoning resemble another student’s, the resemblance is the problem, not the subject.
Understanding the criteria is the first step
When I open an IA, I can usually see where the real difficulty is. I guide you and give feedback on your own work, criterion by criterion. I never write or edit your IA, because the work must be your own. If you want an experienced reading of yours while there is still time to change something, that is what my IA Review and Feedback is for.
Apply for IA Review →