OS Health

OS Health is one number between 0 and 100, and the interesting part is how often it refuses to be a number at all.

It is the unweighted mean of five sub-scores. Not a weighted one — nobody has ever justified the weights on a score like this, and picking some is a way of encoding an opinion while looking like arithmetic.

The five sub-scores

Each one is either a real 0–100 value or Building — a stated absence, rendered as an em dash, with the next action named beside it. Not "insufficient data": "log a few sessions", "add a habit", "link a session to a goal".

Focus, specifically

60% × volume + 40% × completion.

Volume is your deep minutes over the window divided by your own adaptive goal, clamped to 1 — so exceeding your goal does not inflate the score, it just stops helping.

Completion is per-session equal weight. A finished 25-minute sprint counts exactly as much as a finished 90-minute block. It is a ratio of counts, not of minutes, which is deliberate: minute-weighting it would quietly punish anyone who chooses shorter blocks.

Life balance

The number is a normalised spread: mean absolute deviation from an even split, divided by its theoretical maximum, so it lands in 0–1 whatever the number of areas. 0 is perfectly even; 1 is everything in one bucket. The score is 100 × (1 − spread).

The number is allowed to be blunt. The sentence next to it is not. It reads "One area held most of your effort this week" — never "unbalanced", and never "you neglected X". The distinction between an observation and a verdict is the whole product.

The composite

const available = subScores.filter((s) => !s.building);
if (available.length < 2) return null;
return round(sum(available) / available.length);

Below two available sub-scores, OS Health is null — not a low number, not a zero, and not a placeholder. The screen shows the band word Building and the five sub-scores underneath, which is more information than a fabricated composite would have carried anyway.

The bands

There is no danger red. The lowest band is called finding your footing, which is a description of a situation rather than an alarm about a person. An app that turns red at you is an app you eventually stop opening honestly.