Seed odds are each team's chance of finishing as each playoff seed, or of missing the playoffs.
How It Works
We play the rest of the season out 10,000 times (a Monte Carlo simulation; 20,000 for the college league), the same seasons as the playoff odds. Each season is seeded the way the league seeds: record first, then points for, with division winners first where a league has divisions. So a team's seed chances add up to its playoff odds.
The projected bracket puts the likeliest team at each seed, no team twice: the surest team-and-seed pair goes in first, then the surest of what is left (a greedy assignment). The top seeds get the league's byes.
Each round-one game shows the chance one team outscores the other that week, from the same seasons. Later rounds depend on who wins; where a league reseeds, the best seed left plays the lowest.
Keep in Mind
A seed reads 100% only once the regular season is over; until then a seed every simulated season agreed on reads >99%. The bracket is the likeliest seed by seed, not one season expected to happen whole.
When It Updates
With the power rankings: NFL leagues once the week's stats are final, the college league with each daily update.
For the Curious
The single commonest exact seeding was the other way to draw the bracket. With ten or twelve teams it turns up in only a few percent of seasons, and it jumps between updates on noise.