About Project

In the context of the NFL, each team starts with an initial Elo rating, which changes based on the outcomes of games throughout the season. After each game, the winning team's Elo rating increases, while the losing team's rating decreases. The amount of change depends on several factors:

• The difference in Elo ratings between the two teams:

  If a higher-rated team beats a lower-rated team, its rating increases by a smaller amount than if a lower-rated team beats a higher-rated team.

• The margin of victory:

  A larger margin of victory typically results in a bigger rating change.

• Whether the game was played at home or away:

  The Elo system accounts for home-field advantage by giving a slight boost to the home team's rating.

The Elo system provides a more nuanced view of team performance compared to traditional rankings or win-loss records. It factors in the strength of opponents and the context of each win or loss, offering a more dynamic and predictive model. For example, a narrow win against a top team might increase a team's rating significantly, whereas a blowout win against a weaker team might not have as much impact.

The change in a team's Elo rating is calculated using the formula:

Where:
$R_{\text{new}}$ is the new Elo rating.
$R_{\text{old}}$ is the previous Elo rating.
$K$ is a constant that controls how much ratings change.
$S$ is the score of the match (1 for a win, 0.5 for a draw, and 0 for a loss).
$E$ is the expected score.

Understanding the Elo Rating System for NFL Predictions

The Elo ratings are also used to predict the outcomes of upcoming games. Based on the difference in Elo ratings between two teams, the model can estimate the probability of each team winning. These probabilities are used to identify favorites, underdogs, and potential upsets.

Example:

If Team A has an Elo rating of 1600 and Team B has an Elo rating of 1500, the Elo system predicts Team A has a higher probability of winning. If Team B manages to win, it will gain more Elo points, reflecting its better-than-expected performance.