CUBALE: the Concept Understanding Based Adaptive Learning Engine

What CUBALE is

CUBALE is the Concept Understanding Based Adaptive Learning Engine — the AI engine that sits underneath every part of Sublogy. It was built in‑house by the Sublogy team rather than assembled from off‑the‑shelf parts, because the thing it has to model is unusual: not what a student got wrong, but which idea underneath the question they have not yet understood.

Three words in that name are doing real work.

The reason Sublogy needed its own engine comes down to a limitation that every question-and-answer system runs into. A right/wrong check can tell you what happened. It cannot, on its own, tell you why.

How CUBALE identifies foundational gaps

Take a question a class 8 student might see:

A conventional system records one fact: incorrect. But there are at least four different reasons a student could arrive at 775, and they call for four completely different responses:

• They don't know what a percentage represents — so they subtracted 25 from 800.
• They can't reliably find a percentage of a quantity — the arithmetic broke down.
• Fraction–percentage equivalence is shaky — they can't move between 25% and ¼.
• They don't understand discount as a share of the marked price — the word problem, not the maths, is the obstacle.

Only the fourth of these is actually about discounts. The other three are older concepts that the student was supposed to have secured a year or two ago. Re-teaching discounts would not fix any of them.

Why one answer is never enough

CUBALE deliberately does not draw a conclusion from a single response. A single incorrect answer is weak evidence — it could be a slip, a misread, or a distraction. What CUBALE looks at instead is the pattern across many responses that share an underlying concept.

If a student is reliable on questions that need fraction–percentage equivalence and unreliable only on questions that also need discount-on-marked-price, the gap is in discounts. If they are unreliable on every question that touches fraction–percentage equivalence, regardless of the topic wrapped around it, the gap is much older and much more important.

That second case is a foundational learning gap, and finding it is the specific thing CUBALE exists to do.

Why every student needs a different learning path

Two students can give the same wrong answer to the same question for completely different reasons.

Give all three the same remedial worksheet on discounts and only one of them is helped. Student B wastes the time. Student C is set even further back, because the work assumes exactly the thing they cannot do.

This is the honest case for adaptive learning. It is not that personalisation is pleasant, or that students enjoy variety. It is that the same question does not reveal the same learning problem, so the same response cannot be the right one. A learning path is only useful if it is built from what that particular student's answers have actually shown.

And because a class has thirty of these paths running at once, across dozens of interconnected concepts and hundreds of responses a week, working them out by hand is not a matter of effort. There is simply more information than a person can hold.

How unresolved concepts affect future learning

A gap left alone rarely stays the same size. Concepts in a school subject are not a list — they are a dependency chain, and each link carries the weight of everything above it.

1. Fractions — not fully securedNothing visibly goes wrong. The questions at this level are simple enough to get through without real understanding.
2. Percentage — harder than it should beThe student is now doing two things at once: recalling a shaky idea and learning a new one. It takes longer and feels heavier than it does for their classmates.
3. Profit, loss and discount — repeated mistakesErrors become frequent enough to be noticed. Confidence drops. The student starts to describe themselves as “bad at maths”.
4. Multi-step word problems — avoidanceEvery step now rests on something uncertain. The difficulty starts to look like the subject rather than like one unresolved idea from two years ago.

By the time the problem is visible enough to act on, it has been mislabelled. The student looks weak at word problems. The actual gap is fractions, and no amount of word-problem practice will close it.

This is why the timing matters more than the intensity. A gap found at step one takes a short, targeted intervention. The same gap found at step four takes months, and by then it has to be undone as well as taught — because the student now believes something about themselves that isn't true.

How CUBALE identifies and fills those gaps

The engine runs as a loop rather than a one-off diagnosis. Every answer a student gives is new evidence, so the picture is always being revised.

“Filling” a gap, specifically

Detecting a gap is only half of it. What CUBALE does next is choose the work:

• It picks questions at the right level. Practice is matched to what the student has already mastered, so the work stays hard enough to be interesting and easy enough to finish. A student who cannot complete anything stops learning and starts guessing.
• It works on the foundation before the symptom. If fractions are the real problem, the student gets fractions — even though the question they failed was about discounts.
• Every question carries a worked example. Not just the answer, but the steps, written the way a teacher would explain them.
• Help is available at the point of confusion. When a student is stuck mid-step, Sublogy Buddy talks through the example on screen in short, simple sentences.
• It re-checks rather than assuming. A concept is not marked closed because the student was shown an explanation. It is closed when later answers show it holding up.
• Progress is made visible. Students earn belts as they improve, White through to Black, so effort turns into something they can see.

And because the same analysis is running for every student in a class, the teacher gets the summary: which concepts need attention, how many students each one affects, and which individual students are working on what. CUBALE handles the analytical heavy lifting; the teacher decides what to do with it. That is covered in more detail on Sublogy for schools.

How AI is used — and how it isn't

“AI-powered” covers a lot of very different things, so here is precisely what it means inside Sublogy. There are two distinct systems, and they do not do the same job.

What CUBALE is trained on

CUBALE improves using assessment information: whether an answer was correct, the number of attempts, how recently a concept was practised, which question was asked, and which concept was being assessed.

A student's name, username and school name are not used to train CUBALE. It is built to learn patterns about how concepts are learned and which questions suit which stage of learning — that is, to learn about concepts, not about individual children. A student's own progress is of course used during normal app use, to choose their next question.

What we are careful not to claim

CUBALE identifies patterns and detects likely gaps. It surfaces concepts that need attention and recommends areas for reinforcement. It does not read a child's mind, and Sublogy does not claim it knows every misconception perfectly. It adapts on the evidence it has — which is exactly why the teacher stays in the loop, and why every recommendation is shown as something to look at rather than a verdict.

Where the limits are set

• Sublogy Buddy is restricted to the lesson or topic being studied, and its replies are screened for material unsuitable for children before they are shown.
• Nothing identifying the student — name, username, school, account identifier — is sent with a Buddy question.
• Our agreement with the third-party AI provider does not permit Sublogy data to be used to train its models.
• There is no advertising and no behavioural tracking anywhere in Sublogy, and personal data is never sold or rented.
• Data is stored in India.

The full detail is in the privacy policy.

Questions about CUBALE