Improvement Ahead – Philadelphia Eagles 2013 Win Probabilities

by Jerome's Friend

Originally published May 3, 2013 on

The NFL Draft is over, and while we wait for the OTA’s and mini camps, it’s time to focus on the Philadelphia Eagles’ 2013 schedule.  For a Chip Kelly squad that will want to play fast, the NFL *cough* graciously accommodated.  The Eagles open the season with three games in 11 days, and two of those games are during prime time, so we may know pretty quickly how Kelly’s team responds to high speed and short rest.  Hopefully smoothies help.  But in actuality, how might the team perform next season?

Before the draft, I took a cue from Bill James and used Pythagorean expectation to project the Eagles will win five games in 2013.  However, that did not take into account their opponents, who were unknown at the time.  Now that we know who the opponents are, I applied the same Pythagorean expectation formula to them, and used those results as the basis for simulating the Philadelphia Eagles 2013 season.

The model takes the Pythagorean wins for the Eagles and their opponent each week, randomizes those values within the standard error value (2.6 wins), and applies a random “external factor” value to each team.  I included the external factor value to randomly, and cumulatively, account for things like luck, home vs. away games, day vs. night games, win/loss streaks, weather, game planning, the impact of a certain new head coach, etc.  I ran the simulation 1,000 times, so the external factor value changes for each team in each simulated game.  For each game, the products of the modified Pythagorean wins (based on standard error) and external factor values for each team are compared, and the team with the higher product is awarded a win.  Read more…