Aug 21

Regression Facing the Big-Play Defenses and Special Teams

NFL PreviewIn 2012, we thought the Chicago Bears had what it took to reach the Super Bowl. It wasn’t so much the play of Jay Cutler, but the surrounding pieces that would lead Chicago to the NFC championship. In many ways, the team looked every bit the part. The defense looked stellar and the running game was an asset en route to a 7-1 start. However, expectations fizzled out in the second half. Chicago was held to 17 points or fewer five times, leading to five losses during that span. The 10-6 overall record wasn’t even enough to earn the Bears a playoff spot. Once a potential NFC favorite, Chicago wasted an epic season for the defense and special teams.

Led by a defense that returned a league-high eight interceptions for touchdowns, the Bears were able to turn turnovers into quick points. It helped Chicago to need just 13.25 Yards per Point Scored in 2012, a total which ranked third in the NFL, according to Cold, Hard Football Facts. Imagine what could’ve happened had the team averaged better than its 4.97 Yards per Play Total, ranking 28th in the league. The team’s 5.67 Net Yards per Dropback was the weak link for a team that had Super Bowl-level defense.

Here’s a recap of all eight interception return touchdowns for the 2012 Bears:

  1. Week 3: Major Wright returns Sam Bradford interception 45 yards for a touchdown
  2. Week 4: Charles Tillman returns Tony Romo interception 25 yards for a touchdown
  3. Week 4: Lance Briggs returns Tony Romo interception 74 yards for a touchdown
  4. Week 5: Charles Tillman returns Blaine Gabbert interception 36 yards for a touchdown
  5. Week 5: Lance Briggs returns Blaine Gabbert interception 36 yards for a touchdown
  6. Week 8: Tim Jennings returns Cam Newton interception 25 yards for a touchdown
  7. Week 9: Brian Urlacher returns Matt Hasselbeck interception 46 yards for a touchdown
  8. Week 16: Charles Tillman returns Ryan Lindley interception 10 yards for a touchdown

All said, the defense held its own as a Super Bowl contender. The unit limited opponents to 4.95 Yards Allowed per Play, including just 5.41 Net Yards Allowed per Dropback. The Bears also finished second in the NFL with a 71.28 Defensive Passer Rating. However, notice that mid-season regression that happened for Chicago. During the 7-1 start, the Bears tallied seven interception return touchdowns. During the 3-5 finish, the team tallied just one. That’s when the offense was finally exposed.

Also note that the Bears also tallied one blocked punt return touchdowns (Week 9 at Tennessee) and one fumble return touchdown (Week 16 at Arizona), giving the team a league-high 10 total return touchdowns for the defense and special teams. As you will soon see, it’s among the best totals in NFL history, which will led to some guaranteed regression in 2013. Chicago’s offense received 69 “free points,” leading to 2.99 “Free Yards” per Point Scored. This factor will inevitably regress, as outlier tables will soon show. However, the overall impact of this regression is unknown, so we examine this in more depth today.

Charles Tillman (33) celebrates with Lance Briggs (55) after Tillman returns an interception for a touchdown during a Week 4 win over the Dallas Cowboys. (photo rights to Larry W. Smith / EPA)

Charles Tillman (33) celebrates with Lance Briggs (55) after Tillman returns an interception for a touchdown during a Week 4 win over the Dallas Cowboys. (photo rights to Larry W. Smith / EPA)

Now that we understand what went well for the Bears in 2012, we need to understand the impending regression for 2013. To do so, we look at the teams with the most return touchdowns in NFL history and how it affected their Net Yards per Point Scored (NYPPS). As the return touchdowns regress, it’s likely that NYPPS will regress too as long the teams fit into a normal context.

What is that normal context, you say? Assuming there isn’t an outlier of some sorts in the one of the units that leads to strong scoring regression, there is a normal context that would lead to a decline in scoring efficiency. For the Bears, we will address the regression on two different notes, looking at both their interception return touchdowns and overall return touchdowns. Does the return touchdown regression truly lead to scoring efficiency regression? Does that in turn lead to overall regression?

First, we look at the teams with the most interception return touchdowns. No team in history tallied at least six such touchdowns in consecutive seasons, so we can use that a cutoff point for determining the outlier in play. The 2012 Bears became just the 14th team since 1940 in either league (Table 1) to return at least six interceptions for touchdowns, putting them in rare company. However, it also puts the team at risk for some serious regression in scoring efficiency and possibly even win-loss record.

Table 1: Most Interception Return Touchdowns, NFL or AFL, since 1940

Team Total NYPPS Next Yr Record Next Yr
1961 Chargers 9 +6.09 -1.47 12-2 4-10
2012 Bears 8 +4.98 ?? 10-6 ??
1998 Seahawks 8 +5.92 +3.99 8-8 9-7
1999 Rams 7 +7.22 -1.44 13-3 10-6
1984 Seahawks 7 +5.47 +2.68 12-4 8-8
2008 Packers 6 +0.67 +2.17 6-10 11-5
2007 Cardinals 6 -0.39 -1.25 8-8 9-7
2007 Vikings 6 +2.66 +0.10 8-8 10-6
1992 Chiefs 6 +2.91 +1.65 10-6 11-5
1992 Vikings 6 +5.03 -2.22 11-5 9-7
1967 Lions 6 +0.01 -3.51 5-7-2 4-8-2
1967 Oilers 6 +6.80 -0.75 9-4-1 7-7
1966 Packers 6 +9.34 +2.90 12-2 9-4-1
1960 Browns 6 +6.56 +1.08 8-3-1 8-5-1

SOURCE: Pro Football Reference (for Interception Return Touchdown totals only)

If there’s anything to learn, it’s that sample size established a correlation between change in NYPPS and change in win-loss record among the 13 teams above (excluding the 2012 Bears). We get a correlation coefficient of 0.7816 between the two sets of values, indicating a strong positive correlation. Thus, Chicago’s fortunes will lie on improving its scoring efficiency on offense in grassroots, non-return situations. (The defense already ranks third in Yards per Point Allowed, so the unit can’t play much better in that area.)

On the other side of the coin, note that five of the previous 13 teams actually improved their record the following season. Therefore, interception return touchdowns aren’t a strong indicator of overall regression the following season.

Perhaps this is so because the return touchdown totals are not high enough. Perhaps it is simply because return touchdowns have an indirect impact on the team’s success. (Rather, that return touchdowns lead to better scoring efficiency, which thus leads to greater team success.) We can determine this better by looking at the overall return touchdown totals (Table 2).

Table 2: Most Overall Return Touchdowns, NFL or AFL, since 1940

Team Total NYPPS Next Yr Record Next Yr
1998 Seahawks 13 +5.92 +3.99 8-8 9-7
2010 Cardinals 12 -1.14 -0.31 5-11 8-8
1999 Chiefs 11 +2.01 -0.90 9-7 7-9
1999 Rams 11 +7.22 -1.44 13-3 10-6
1992 Chiefs 11 +2.91 +1.65 10-6 11-5
1961 Chargers 11 +6.09 -1.47 12-2 4-10
1952 Rams 11 +3.18 +1.75 9-3 8-3-1
2012 Bears 10 +4.98 ?? 10-6 ??
2004 Bills 10 +3.01 -0.23 9-7 5-11
1998 Saints 10 +1.16 -6.91 6-10 3-13
1997 Broncos 10 +3.83 +3.81 12-4 14-2
1997 Chargers 10 -4.78 -6.75 4-12 5-11
1986 Chiefs 10 +3.35 -1.65 10-6 4-11
1976 Broncos 10 +5.00 +11.25 9-5 12-2
1951 Giants 10 +7.05 +2.13 9-2-1 7-5

SOURCE: Pro Football Reference (for Overall Return Touchdown totals only)

Once again, the correlation between NYPPS change and win-loss record change suggests a strong positive relationship. Actually, the correlation coefficient is slightly stronger at 0.8027, likely because this sample size has one more team (14) than the first sample size (13). This is especially important to note, because our sample size isn’t yet sufficient. Despite this realization, we will use six interception return touchdowns and 10 overall return touchdowns as our upper bound to determine an outlier.

While that correlation remains, we still don’t see guaranteed overall regression. Six of the 14 teams improved the following season, again following a similar route to our first table. Furthermore, with the top two teams in this table both owning a better respective succeeding record, we can dismiss any notion that return touchdown regression has a direct correlation to win-loss record change.

Like with most of the elements in this game, return touchdowns give us only one piece of the puzzle. That piece of the puzzle could be important or generally meaningless, depending of the context of the situation. You certainly will learn more about that this weekend, when we debut our “Five Factors of Regression” feature in the 2013 NFL Preview.

This factor will be an important factor to note for the 2013 Bears, given the context at hand. The team’s defense can’t get much stingier in scoring efficiency, while the offense needed more than 16 Yards per Point Scored when the return touchdowns are excluded. If the 2013 Bears offense cannot improve, or the defense experiences some grassroots decline, they will decline in overall record. However, if the offense can find a way to legitimately compensate the inevitable regression in “free points” for the unit, the 2013 Bears can actually be in better shape to reach the postseason and make a run at a Super Bowl championship.

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