Simulating the Game: Eagles vs. Redskins

Yes, beware the bye. If the 2013 version of the Philadelphia Eagles would like to make a serious push for the playoffs, then they cannot look forward. Head coach Chip Kelly has never lost a game before the bye, but then again, he's never had one this late in the season either. His challenge will be to keep his players focused on the Washington Redskins and maintain a one-game-at-a-time attitude.

The challenge is palpable. This Redskins team is not the same team the Eagles played Week 1; Robert Griffin III gets healthier every week. Despite their 3-6 record, the Redskins have averaged nearly 31 points per game their last four games, they have a season Offensive Effieciency Rate (OER) of 71%, the same season OER as the Eagles, and they come into Lincoln Financial Field, a stadium that has seen non-Philadelphia teams ride a ten-game winning streak.

According to the simulation, this game could be a close one. The Eagles have a very slight advantage, winning 52% of the time by an average of 0.7 points. Their home field advantage has been so lackluster lately, even if losing one more turnover than the Redskins, they lose 72% of the time.

This game needs to be all about the defense. If the Eagles' defense can keep the Redskins at or below their season OER, and the Eagles' offense performs at or above theirs, they win 62% of the time by an average of 4 points. If turnovers are equal, they win a whopping 96% of the time. Let's hope Billy Davis is right: sacks come in bunches and RGIII will stay on his ass. Interact with the viz to see more:

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Note: NFL simulations are far from an exact science. They attempt to mathematically project the future based on history and past performance, but they can’t account for everything. A stiff breeze, a tipped ball, a freak injury, a rolling fog bank, an ol’ coach’s return, or simply a change in player attitude can alter results in a large way. Instead, simulations give us a blurry view of a series of possibilities among an infinite number of potential realities. But they’re fun. If you believe in parallel or multiple universes, then one of these simulated results could possibly occur.

*Simulation Details

The simulation is based on my home field advantage (HFA) research, which shows how there have been small but distinct and different offensive efficiency behaviors between home teams and away teams in the NFL. And not surprisingly, turnovers play a large role in equalizing the playing field. Offensive performances throughout the season were entered into a logistic regression formula born from the HFA research, and randomized according to standard error values and turnover differential.

Step 1: Calculate Offensive Efficiency (OE). I used Chip Kelly’s definition for this:

(Rushes + Completions) / (Total Off Plays + Offensive Penalties)

If you check out the HFA research, there’s a really strong correlation between offensive efficiency and team success.

Step 2: Calculate Win Probabilities using the logistic regression formula that correlated OE to team success. Here’s the formula:

Win Probability = 1 / (1 + e^-((A*OE+error value) + (B*Turnover Diff + error value) + C)), where A, B, and C are constants.

Step 3: Convert the results from Step 2 into points using a linear formula:

Points = A*(Win Probability for Eagles) + B*(Win probability for Opponent) + C, where A, B, and C are constants.