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Measurement

What iQuantize actually measures

Updated 27 August 2026

Six skills, one shared vocabulary

The list is not a scoring gimmick invented for an app — it is the vocabulary a teacher already reaches for. Note accuracy asks whether the notes you were given actually landed; a low score there means notes you know are missing, not a subtle nuance.

Timing splits into three separate numbers, covered in their own section below, because keeping them apart is the most useful thing this page can tell you.

• Dynamic control failing sounds close on tape and reads flat on the chart: the ghosts and accents land, in the wrong zone. The ghost-notes guide has the drill for it.
• Limb independence failing is your feet arriving a beat late once the hands get busy, which is what that guide spends its time on.

Timing with the click, versus timing stability

Timing with the click measures distance from the grid: how close each hit sits to where the chart says it should land, while the click is audibly running.

Timing stability measures distance from yourself: how tightly your hits cluster around your own average, regardless of whether that average sits early, late, or dead on the beat.

Picture someone whose every hit lands 15 ms behind the click, and lands there every time. iQuantize tells them so — the per-bar map reads 8 notes late (+15 ms) — and still scores them in the mid-90s for timing with the click and close to 100 for stability. It names the offset without marking them down for it, because sitting a fraction behind the beat is a choice a lot of good drummers make on purpose.

What moves the numbers is not where your average sits. It is how far your hits scatter around it. The same player with a dead-centre average and 60 ms of scatter drops into the high 60s on stability, and the finding that comes back reads: The beat spacing is uneven. In bars 5–8, the spacing between repeated notes changes.

So the two ask for different work. A consistent offset moves once you know it is there — listen a fraction earlier, or shift where your ear expects the beat to sit. Scatter is a control problem, and no single nudge fixes it; it takes slower, more deliberate reps until the hand does the same thing twice. Rushing vs dragging has the drill for each.

Two more it keeps out of your profile

Two more things sit in the app's own bookkeeping but stay out of your skill profile. One is reading. The app cannot tell whether you were sight-reading that chart cold or playing something you have known since you were fourteen, and those are not the same achievement, so it does not put a reading number on you.

The other is tempo readiness: whether this groove is clean enough for you to push the metronome up. That steers what comes up next instead of appearing as a skill, because “ready for 96 BPM” is a decision about your practice, not something you would recognise as a strength of your own. You can still see it in a groove's History.

When a skill is left blank

A skill iQuantize could not measure shows no number at all — never a zero. A zero says “you failed this”; a blank says “we do not have enough to judge”, and those are different things to put in front of someone practising alone.

• Internal pulse needs bars with the click switched off, after a count-in and with guide drums off. One such bar gives a low-confidence reading, two give a medium one; without them it comes back as not measured.
• Limb independence is only assessed when the chart actually asks the feet to do something independent of the hands. A hands-only chart does not get a free, meaningless 100.
• Dynamic control waits for setup. If the velocity zones are still at their defaults, the app asks you to set them first, so ghost notes and accents match your kit. If your kit sends nearly the same volume for every hit, it says so: there is no way to grade soft against loud when the hardware is not sending the difference.
• Note accuracy below 55% stops the rest of the report. You cannot read the pocket, the dynamics or the limb balance of a groove that was not really played.

One take is a snapshot; the shape takes weeks

Six numbers from one take describe one groove on one evening, which is not enough to plan a month around. Every completed take stores its results, and tapping a skill in Progress opens two charts for that skill alone: a daily average over the last 30 days, and a weekly average over the last 30 weeks. Timing stability on a Tuesday means very little. Timing stability across eleven weeks is the thing you are trying to move.

There is also a way to start from a measurement instead of a guess. The Skill Checkup is a 24-bar evaluation groove at 80 BPM, about 1:20 long, in one of three versions matched to your drumming experience. Each one switches the click off for two short stretches. One take is enough; with two it averages them, with three it takes the middle. Out of it come the same six skills and a Learning Plan: up to six named grooves from the library, each with one line saying why it is on your list.

Why this vocabulary matters

A student who knows their weakest of the six knows exactly what to put in front of the kit on Tuesday, instead of guessing at “tightness” in general. A teacher who can see the same six numbers does not have to spend the first ten minutes of a lesson working out what happened last week — they can start from where the chart says the gap actually is.

There is no dashboard and nothing to send. The two of you look at the same screen on the student’s own device, which is the whole mechanism, and for a weekly lesson it is enough.

The six skills

Note accuracy

Whether the notes the chart asked for actually landed, with extra hits counted against you.

Timing with the click

How close each hit sits to the grid while the click is running.

Internal pulse

Whether tempo holds through a section where the click drops out.

Timing stability

How tightly your hits cluster around your own average — independent of being early or late.

Dynamic control

Whether ghosts, normals and accents land in the zone the chart asked for.

Limb independence

Whether your feet keep up with what your hands are doing.

Common questions