British Cycling hired Dave Brailsford in 2003. His theory was that if you find one percent in the saddle, one percent in the pillow a rider sleeps on and one percent in how the team washes its hands, the small stuff compounds into something no single fix can buy. Britain won eight cycling golds in Beijing and eight more in London.
I wanted that as a number on my own habits, and the naive version does not survive contact with arithmetic.
Why literal compounding fails
One percent a day for a year is 1.01^365, about 37x. If your habit score is bounded at 100 and you are sitting at 70, the whole runway from 70 to 100 is only 1.43x. You run out of room in roughly five weeks, and every day after that is a failure by construction.
So the target is not compounded from a fixed origin. It is:
target = min(100, EWMA_14(score) * 1.01)
A 14 day exponentially weighted baseline, plus one percent, capped. The half life is 14 days on purpose, so one heroic Sunday does not set an unreachable bar for Monday. On a bad week the baseline sags and the target comes back within reach, which is the behaviour you want from something meant to restart a habit rather than grade it.
What the score is made of
score = 100 * (0.70*cadence + 0.15*recovery + 0.15*breadth)
Cadence is earned over owed, per habit, weighted. Recovery asks how often one miss turns into two, over a trailing 28 days. Breadth is how many habits are still alive in the last 14 days, measured against your own peak rather than a constant I invented.
Nothing is stored. The whole series is a pure function of which days you checked off, replayed on the client each time the tab opens, which means changing a habit's weight retroactively moves the entire history instead of leaving a stale number on a row.
Habits are not one shape
A habit is every day, or N days a week where the rest days are genuinely free, or bonus only, where logging adds credit and skipping is never a miss. Each carries a weight between half and triple, applied symmetrically: doubling what a habit earns also doubles what missing it costs. An asymmetric bonus would let one habit paper over another's miss, which defeats the point of a single number.
A month of clean cadence banks a spare, spent automatically on the first missed period. A streak that resets on one miss mostly punishes the week your mother visits and cooks, which is not a lapse in the habit.
Logging happens by tapping an NFC chip stuck where the habit actually happens. Full write-up and a clip of it running: https://voidcraft.world/blog/one-percent-better.html
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