One number, built from live public data and graded against Seattle's own record. The best the city has ever been on each measure is a 90; the worst, a 10.
Most "city ranking" sites compare cities against each other, which buries the question people actually ask: is my city getting better or worse? How is Seattle? answers that by grading Seattle against itself.
For each measure, we take every year on record from its public source. The healthiest value the city has ever posted is pinned to 90; the worst to 10. The most recent value is scaled linearly between them:
A new all-time record can push a measure past 90 (toward 100); a new low can sink it below 10. That keeps the number honest and always explainable: you can see exactly which year set the ceiling and which set the floor. The headline grade is the weighted average of every live measure.
Weights reflect how much each measure shapes daily life in Seattle, and they're shown on every card. These are an editorial judgment expressed as math, stated plainly, not hidden. Every number links to its public source; nothing here is estimated or invented. Measures are added as their live data is wired up, and the score reflects only what's actually measured today.