There has been a lot of excitement among Bears fans about John Fox this offseason.  They cite his 119-89 career record (0.572 winning %) as a head coach, and think it means similar good results are coming to Chicago.

I don’t mean to rain on anybody’s parade, but Fox’s record as a head coach is a bit overinflated.  He’s not a bad coach by any means, but he’s also not a great one.  Let’s dig in to the numbers to find out why.

Peyton correction

For one thing, Fox’s career winning percentage is skewed by the three years he spent with Peyton Manning.  You’ll pardon me for not crediting Fox when he had the greatest regular season quarterback in NFL history, fully developed, drop into his lap. In 10 years without Peyton, Fox averaged 8.1 wins per year and made the playoffs 40% of the time.  In 9 seasons over the same span (which correlates nicely to Peyton’s prime), Peyton’s teams averaged 12.4 wins and went to the playoffs 100% of the time.  In 3 seasons together, they averaged 12.7 wins and went to the playoffs 100% of the time.

Fox’s presence had basically no change on the outcome of Peyton’s seasons, while Peyton’s presence drastically improved Fox’s outlook.  So let’s look at Fox’s results without having them skewed by the Peyton years.

Who does he beat?

Let’s start by looking at game outcomes.  As I mentioned above, Fox is 81-79 in ten years as a coach without Peyton Manning.  I want to look at who those wins and losses come against.  I split up teams into three loosely defined categories: good (10+ wins, so typically playoff teams), average (7 to 9 wins), and bad (6 or fewer wins) and looked at Fox’s winning percentage against each category.  In order to adjust for the quality of opponent, I compared that winning percentage to what the expected winning percentage would be.  For example, Fox went 11-43 against 54 opponents with 10 or more wins, and those 22 opponents averaged 11.3 wins in the seasons Fox’s team played them.  Thus, opponents posted a winning percentage of 29.5% (4.7 wins in a 16 game season) against them.  Full results can be seen in the table below.

This provides some interesting results.  Fox’s teams did worse than expected against playoff-caliber teams, better than expected against average teams, and about as well as expected against bad teams.  Fox has a reputation for being a conservative manager in-game, and that perhaps plays out in his record against the top teams in the NFL.  You have to be more aggressive to beat good teams, who are not going to make mistakes and beat themselves.

Or this could simply indicate Fox’s teams (outside of the Peyton years) have not had top-level talent to compete with top teams, but they are still disciplined enough to beat everybody else.  Whatever the reason, Fox’s teams have struggled to beat playoff-caliber opponents.

Offensive and defensive production

Now I want to examine how Fox’s teams have fared on both offense and defense.  Like with win percentage, I looked at how many points Fox’s teams scored and gave up compared to what their opponents averaged that year.

Over the 160 game sample, Fox’s offenses scored an average of 19.4 points per game against defenses that gave up an average of 21.7 points per game, meaning Fox’s offenses have performed an average of roughly 2.3 points worse than expected as a whole.  On the defensive side of the ball, things look better.  Fox’s teams have given up an average of 20.6 points per game against teams that scored an average of 21.6 points per game, meaning they have been roughly 1.1 points per game better than expected (rounding error, the actual results are closer to 1.1 than 1.0).

Like with winning %, I broke down the results by quality of opponent, based on their offensive or defensive ranks in points allowed or scored, but this time there wasn’t really a clear pattern for either offense or defense.  The full results are shown below for offense and then defense.

Party like it’s 2004-12

So what have we learned? The Bears have a defensive-minded head coach who couples a below-average offense with an above-average defense, beats the teams he should, loses to the top teams, and ends up right around average.  Sound familiar?

Fox is Lovie.  Lovie is Fox.

In 10 seasons as a head coach, Lovie Smith is 83-77; in 10 seasons without Peyton Manning, John Fox is 81-79.  Fox’s offenses have scored about 2.3 points less than expected, while his defenses have given up 1.1 points fewer than expected.  For Lovie, those numbers are 1.7 and 2.1, indicating that his offenses have been slightly less bad than Fox’s and his defense’s a good bit better.

If there is one noticeable difference between the two, it is who they beat.  Lovie does about as well as expected against 10+ win teams (32% wins vs. 30% expected), worse than expected against average teams (43% wins vs. 51% expected), and better than expected against bad teams (78% wins vs. 72% expected).  Incredibly, Lovie has never lost a game against a team 4-12 or worse (25-0) in his career, and he’s also done a better job than Fox competing against other playoff-caliber teams, although he has been much worse against average teams, where Fox excels.

If Fox has one clear advantage over Lovie, it is that he has assembled a much more complete coaching staff than Lovie ever managed to do in Chicago.  Bears fans can only hope that makes a significant difference.  Otherwise, there are worse fates than simply being respectable, as we saw when Mark Trestman ruined ran the Bears.  If Fox keeps the Bears competitive and around .500 for 4-5 years by beating average and bad teams, then retires and leaves the franchise in solid condition for the next guy, I would consider that a job well done.