Lead-changing pick-6s
Most big plays move a game a little. A lead-changing pick-6 moves it twice in about ten seconds: the offense loses a drive that might have scored, and the defense scores instead. One throw, and the team that was losing is winning.
It's rare, too. The NFL averages about 14 a season, fewer than one a week across the whole league, and roughly two out of three teams that get one go on to win the game.
Every play is ranked by its win-probability swing: the defense's chance of winning just before the snap, compared with just after the extra point. Kiko Alonso's 60-yard return for Miami in a 24-24 game with 1:13 left took the Dolphins from 27% to 95%, a 68-point swing and the biggest in the NFL since 1999.
Win probability comes from open models built on decades of play-by-play. Given the score, the clock, field position and down and distance, they estimate how often a team in that spot goes on to win. The NFL model leaves out betting lines, so the numbers reflect the game situation alone.
NFL plays come from nflverse play-by-play (nflfastR), 1999 to present. College plays come from cfbfastR and the SportsDataverse, covering games with at least one FBS team. Both are free, community-built projects, and this site wouldn't exist without them.
New Flip Sixes as they happen, plus On This Day throwbacks, on X at @flippicksix.