It’s been well-documented that the Cowboys ranked last in the NFL in defensive interceptions last year with only seven. That’s actually a positive heading into 2013 simply because there’s almost no chance that the ’Boys won’t increase their interception total, perhaps substantially, so their record should improve if they play just as well otherwise.
It’s not as well-known that the Cowboys also ranked in the bottom half of the league in forced fumbles (15). That might seem like a coincidence, but I think the Cowboys’ low ranks in both categories, interceptions and forced fumbles, stems from the same fundamental issue: a lack of pressure. Last year, I showed that defensive pressure and takeaways are strongly linked; the more you can get after the quarterback, the greater the probability of forcing a turnover.
With the 2012 season over, I can now look back at an entire year of data to see which teams were really the best at generating takeaways. It turns out that the strength of the correlation between pressures, as tracked by Pro Football Focus, and forced fumbles was 0.36 in 2012. In other words, we can explain around 36 percent of all forced fumbles based on defensive pressure, which is a pretty high number given that we know fumbles are fluky.
Even more surprising, the strength of the correlation between pressure and interceptions was 0.45. Since pressure can often lead to strip sacks, you’d think the two would be more strongly correlated than pressure and interceptions. The fact that you can explain 45 percent of 2012’s interceptions with team pressures is amazing. Again, since we know there’s a lot of randomness involved with turnovers, the numbers suggest that the strongest indicator of potential takeaways is a potent pass-rush.
Visualizing Pressure and Takeaways
Another way to examine the relationship between pressure and takeaways is to compare the league’s best and worst pass-rushing teams. Below, I charted the number of forced fumbles and interceptions for the top 10 and bottom 10 teams in terms of total pressure.
The results are pretty obvious; if you get to the quarterback, good things will happen. The top 10 pass-rushing teams in the NFL last year totaled an average of 36.1 forced fumbles and interceptions. Meanwhile, the bottom 10 teams checked in at just 25.3. For the record, Dallas ranked 23rd in pressures, so they were one of the teams listed in the bottom 10.
On the Field
I think this data suggests two things. The first is that NFL teams should force the issue on defense. Ideally, you’d like to generate an effective pass-rush without blitzing, which is what many expect Monte Kiffin to be able to do in Dallas. However, it’s probably suitable to send five rushers over rushing four and failing to get pressure. Pressure is obviously valuable in regards to sacks, but even more valuable are the takeaways that effective pressure can generate. With NFL offenses improving each year, the value of each possession increases. Consequently, the value of each takeaway does the same.
Second, defenses should be built at the line-of-scrimmage. Cornerback is undoubtedly an important position, but there’s no substitute for a dominant defensive end or interior pass-rush. If you want to see