Making sense of the Chicago Bears 2015 season is important for obvious reasons - what do the Bears do well and where does the team go from here to get better. We can get at some of that by taking a look at the season long statistics as Josh Sunderbruch did earlier this week. If we dig in a little deeper, there are two stats that really help tell the story for this team.
The first is Turnover Differential - the number of turnovers created minus the number of turnovers committed. This is one of the most consistent indicators of how good or bad a team will perform. This season, the Bears finished at -4, indicative of a 6-7 win ball club. While Cutler's late barrage of picks didn't help the overall ratio, this team wasn't able to create turnovers at a rate to help win ballgames.
This graph simply charts every NFL team on the number of wins vs. their turnover differential. The Bears are indicated by the orange square, the red circles are playoff teams, and the blue diamonds are everyone else. The line through the middle of the data points is a simple linear trendline. I have labeled a few interesting cases. The 15-1 Panthers led the way this season with a +20 TO differential en route to the #1 seed in the NFC. The Broncos were an interesting case as they finished the year at -4 like the Bears, but managed 12 wins. With Peyton Manning's struggles at turning the ball over, this should show just how good the defense is for this team to have won 12 games.
The Giants had a great TO differential of +7 but only won 6 games so this isn't a perfectly predictive indicator but you have to be an awfully good team to overcome negative turnover differential and the Bears were not that type of good this season. 11 of 12 playoff teams had a positive differential and this is one of the most reliable statistics year to year. The takeaway here is that the Bears need to get more talent on defense to create more turnovers. That means improving the pass rush and getting playmakers in the secondary. Vic Fangio's 49ers defenses were one of the better teams at taking the ball away so there is hope.
For those of you who want to pin this on Cutler or the offense, there is always room for improvement there too. I would be more concerned with the 20 fumbles (9 lost) than the 12 interceptions (11 for Jay) but as long as Jay Cutler is the quarterback, there will be turnovers. Plus, 11 INTs comes in about league average tied with Drew Brees and Carson Palmer. Having said that, the offense will need to continue to take care of the football and strive for improvement.
The second stat worth exploring further is red zone efficiency. How many possessions that get inside of the opponent's 20 yard line are finished with a TD and, on the other side, how many possessions can you prevent your opponent from scoring once they get inside the 20. The Lovie Smith defenses of yesteryear were good at playing the "bend-don't break" style of defense, forcing a lot of field goals. This year's club wasn't so good, allowing TDs on 60% of red zone drives. That was tied for 21st and was actually worse than last year.
Offensively, that statistic was worse. The Bears managed to score a TD on only 49% of their red zone trips, good for 26th in the league. The Bears clearly missed a healthy combination of Martellus Bennett and Alshon Jeffery this season. The answers to this problem on the offensive side of the ball are likely already on the roster, but it couldn't hurt to upgrade the offensive line and show a willingness to finish drives on the ground.
Many other team stats come out even, indicating an average team. The Bears sacked opponents 2 more times over the season than what they gave up to opposing defenses. Yardage was virtually dead even, with the Bears throwing for about 90 more yards than their opponents but giving up 80 more yards on the ground. Even the explosive plays (runs 12+ yards, passes 20+ yards) were virtually identical with 75 for the Bears and 78 for the opponents.
A look at the numbers indicates that this was an 8 win ball club but with a negative turnover differential and with negative red zone efficiency numbers, a couple of those close games got away. When you played in 11 games decided by one score (12 if we count the 1st GB game), the margin for error is razor thin. That may be little consolation to many fans, but considering the defensive rebuild and the injuries that plagued the offense this last year, there is every reason to believe this team is trending in the right direction.