Strength: a kinder number beside the streak

A streak is brutal by design: miss a week and it’s back to zero. That’s what makes it work, and it’s also why people quit after breaking one. So each habit has a second number, strength, in the spirit of Loop Habit Tracker’s habit score: slow to rise, slow to fall.

The first version was wrong

Strength started as a rolling average over days. The problem showed up on Mondays: a three-days-a-week habit, freshly into a new week with nothing done yet, looked like it was failing. The number dipped every week at exactly the point where nothing had gone wrong.

Weeks, not days

It’s now an average over weeks of how much of each week’s target you met:

values = [min(1.0, c.days / c.target) for c in weeks
          if c.status != "paused" and (c.status != "open" or c.days >= c.target)]
score = values[0]
for value in values[1:]:
    score += 0.25 * (value - score)

• Each week counts as the fraction of its target you met.
• The week in progress only counts once it’s met, so a Monday isn’t a failure.
• Paused weeks are skipped.
• Each new week moves the score a quarter of the way, so it has about a month of memory.

A missed week dents it; it doesn’t erase months. The habit page says exactly that under the number, because a score nobody can explain is a score nobody trusts.