Simulating the Game: Eagles vs. Packers

What Nick Foles accomplished last Sunday was nothing short of remarkable. On this one day he was better than 99.9% of NFL quarterbacks who have ever played the game. He was precise and decisive. He was quick and gritty. More importantly, he was everything against the Oakland Raiders that he was not against the Dallas Cowboys. Have there ever been more extreme performances in consecutive games played? Ever? With the better performance on the latter side of a concussion? Hard to fathom. But in order for Foles to be seriously considered as the Eagles’ quarterback of the future, and not brushed under Peyton Manning’s Omaha-style rug, he needs to perform on the "better" side of his spectrum against the Green Bay Packers.

Green Bay, on the other hand, will be without Aaron Rodgers, who fractured his collarbone Monday night against the Chicago Bears. Seneca Wallace, his replacement, will most certainly not provide the same advantage for the Packers as Rodgers would. However, Wallace will be facing an Eagles defense whose recent improvement is based on a bend-don’t-break mentality, a mentality no more evident than last week. Billy Davis’ unit gave up 20 points against the Raiders but a season high 560 yards of total offense. That 560 yards is the fifth most given up by an Eagles defense in team history, and the most given up since a 49-21 loss to the Denver Broncos in 2005.

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Given Foles’ extreme up-and-down play, an Eagles’ defense capable of bending under the weight of very heavy yardage, and a Green Bay team playing without its All-Pro quarterback, I’m not quite sure how to translate the results of this week’s simulation. Based on the Packers’ 74.8% offensive efficiency rate (OER), and the Eagles 70% OER, the Packers win 57% of the simulated games by an average of three points.

But with Rodgers absent, I would expect the Packers’ OER to be below the season average. And if Foles’ play is closer to his play against Oakland than Dallas, I would expect the Eagles to have a favorable advantage, even at Lambeau. Of course, turnovers are always the great equalizer, but I think this week’s game will be all about efficiency on offense. If the Eagles play above their season OER and hold the Packers to below their season OER, then the scale tips in favor of the Birds, winning 55% of the simulated games by a close margin. 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.