AxiomHow ratings work
Every topic you practise tracks your skill with a rating inspired by Glicko-2 — the same family of systems used in chess and competitive games. Here's exactly what the numbers mean.
The basics
For every parent topic in every subject, Axiom tracks three independent ratings — one for each style of question you might be asked.
Fast recall and procedural fluency. Single-step problems.
Exam-style questions worked by hand. No calculator assistance.
Exam-style questions with the CAS calculator available.
Every rating starts at 1500 when you first sign up and moves up or down as you practise.
Rating tiers
Your rating is also given a label so you can see at a glance where you stand. The label updates automatically as your number moves.
What the ? means
Alongside every rating, Axiom tracks how confident it is in that number — a value called the rating deviation. A fresh rating starts with a deviation of 350, which is high — the system doesn't know much about you yet. As you play, the deviation shrinks because the system gathers evidence about your real skill.
The ? next to a rating means it's provisional — there isn't enough data yet to consider the number reliable. Keep practising and it'll go away.
Concretely, the ? stays until the rating deviation falls below 100. That usually takes a handful of sessions across each question format.
Topic and subject averages
The Ratings page combines your three question-format ratings into a single number per topic, and your topic ratings into a single number per subject. The rules are designed so the displayed rating only ever reflects performance you've actually demonstrated, while the ? stays until you've covered everything.
In short: your rating only counts what you've done, but the ? only goes away when you've done everything.
A worked example
Suppose you've played several Exam 1 sessions on Calculus and settled at 1575. You've also played a handful of Exam 2 sessions and currently sit at 1499, but your deviation is still high so a ? appears next to it. You haven't touched Drill at all.
Your Calculus rating is the average of the two question formats you've practised: (1575 + 1499) / 2 = 1537. Drill isn't included because you haven't tried it yet — using the default 1500 would imply performance you haven't demonstrated.
The ? still appears next to 1537 because two of the three question formats still have high deviation — the system isn't confident about your overall Calculus skill yet.
Why your rating moves
Every question you answer is treated like a match against an opponent of equivalent difficulty. Your rating goes up if you do better than expected, and down if you do worse. The size of the move depends on two things:
- How surprising the result was. Beating a tough question moves you more than beating an easy one.
- How certain the system is about your current rating. When your deviation is high (early on), changes are larger and faster. As the system gets more confident, changes shrink so random luck doesn't throw your rating around.