Elo ratings are a relatively simple rating system originally developed by the physicist Arpad Elo to rate chess players. The system can be easily adopted to other head-to-head competitions, and that’s just what Nate Silver of fivethirtyeight.com did in 2014 when he extended the ratings system to football.
Elo ratings estimate each team’s skill level using only the final scores of previous games and the locations of each game. That skill level is translated into a points system where an average team has 1,500 points, and teams usually fluctuate somewhere between 1,300 and 1,700 points. The Cowboys for example are currently ranked 14th overall with a middling 1,517 Elo points.
Using those points, the Elo system can calculate an expected point spread and win probability for the next opponent.
The Cowboys’ next opponent, the Lions, are ranked 20th with 1,497 points, which gives the Cowboys an Elo point spread of -3.5 and a win probability of 62%. And what can be done for the Lions can be done for all of the remaining 2018 opponents. Here’s what that looks like, according to fivethirtyeight.com:
The title of this post gave it away early, the Elo ratings system currently sees the Cowboys finishing the season with 10 wins. How’s that possible you might ask?
- It starts with a little win streak: The Elo system favors the Cowboys in the next three games against the Lions, Texans, and Jaguars, which would have the Cowboys at 4-2 after six games.
- After that, everything goes south again: The Cowboys are projected to lose three of their next four games, including losses in Washington, in Philly, and in Atlanta. That leaves them at an unimpressive 5-5 after 10 games.
- And then the Cowboys get hot: The win projections above have the Cowboys winning five of their last six games to finish the season 10-6. Sure, that includes the game against the Saints in Week 13 which the Elo ratings have as a pick ‘em. I picked the Cowboys. So sue me.
But that projected 10-6 record is not written in stone, not by a long shot.
The Elo rating system always improves a team’s Elo rating after a win, just as it always reduces a team’s rating after a loss. And the system also factors in margin of victory. A convincing win against the Lions on Sunday could improve the team’s rating to such a degree that the win probability for a game like in Week 7 in Washington might swing in the Cowboys’ favor. And already we’re at a projected 11-5.
Of course, that works both ways: If the Cowboys put up another stinker against the Lions, a lot of the games that currently have the Cowboys as slight favorites might suddenly have the Cowboys as underdogs. And just like that the Cowboys could be looking at a 6-10 record, which you’ve probably already deduced from the table above if you’re a glass-half-empty kind of person.
Either way, the season is far from over, and it can develop in wildly different ways. Right now, anything between a playoff spot and a top 10 draft pick is still possible.