Elo rating
also: Elo · team rating
Our team rating, updated after every game from the score and where it was played, and pulled toward average each offseason.
expected win = 1 / (1 + 10^(-(rating diff + home advantage) / 400))Every team starts a season near its last rating. A win moves it up by how surprising the result was, scaled by a margin-of-victory multiplier so a blowout counts for more than a one-point game. Home court is added to the home team's side before the expectation is computed.
Between seasons we regress each rating a quarter of the way back to the mean, because rosters change. The ratings run for the NBA, the WNBA and both college leagues from every game we hold.
Elo knows scores, not rosters. A star injury or a trade shows up only after the games, so treat a rating as a prior, not a lineup-aware forecast.
Where to get it
Related
Elo rating from the API
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