We've all been sitting in front of the television watching the 'Boys move the football down the field, only to see the drive stall because of a penalty. A false start on 3rd and 1 can certainly make your blood boil, as can a late-thrown penalty flag for illegal contact on what otherwise would have been a three-and-out. For me, the worst of the little yellow flags is the one that comes as the result of a questionable roughing the passer call. We all know penalties at key moments can be debilitating to a team, but I wanted to determine just how much penalties can affect a team's chances of winning. I collected data on all NFL penalties since 2006, and the results are pretty interesting.
Over the past six seasons, teams that finished in the bottom 10 in total penalties (meaning they racked up the most infractions) won an average of 7.7 games per season. For those squads that finished in the top 10 in total penalties, the average win total jumped to 8.5. That might seem inconsequential, but remember that's a sample size of over 1,500 games. Penalties are called on around 10 percent of plays, and if a team can win an extra game per year simply by cutting down on this small subset of plays, that's a pretty good deal.
As you might expect, there's an even stronger correlation between penalty yardage and winning. Five-yard false starts are annoying, but they're obviously not as damaging to an offense as a 10-yard holding penalty, for example.
Of course, the number and nature of the penalties your opponent commits also affects win percentage. Since 2006, teams that have finished in the top 10 in penalty yard differential (opponent penalty yards minus penalty yards accrued) have won 8.6 games per season. Those in the bottom 10 have compiled only 7.5 wins per year.
In the graph above, you can see teams that have landed in the top 10 in penalty yard differential have won more games than the bottom 10 teams in five of the last six seasons.
Despite these results, I don't think it behooves a team to do everything in their power to limit penalties. Some penalties come as the result of physical, aggressive play. Roughing the passer is obviously a demoralizing and harmful penalty to a defense, but the style of play that leads to some of these penalties – aggressive and hard-nosed – is valuable to a defense. In short, some penalties are inevitable if you want to maintain an attacking style of play.
One such penalty that can result from an aggressive mindset is defensive pass interference. The Cowboys are no strangers to flags for pass interference; the defense finished in the bottom half of the league in each of the last six seasons. They racked up the fourth and seventh-most defensive pass interference penalties in 2011 and 2010, respectively.
On paper, everything adds up for defensive pass interference to lead to defeat. The call itself can be incredibly disadvantageous to a defense, providing the offense with the ball at the spot of the foul, plus an automatic first down. On top of that, you'd expect poor defenses to commit more pass interference infractions because they get out of position. Lastly, bad teams tend to have their defense on the field a lot, i.e. more time to accrue penalties.
However, teams that generate a lot of pass interference calls aren't actually more likely to lose than those that limit the penalty. Since 2006, teams that have finished in the top 10 in defensive pass interference (meaning they were flagged the least often) have won 7.9 games per season. Those in the bottom 10 have won 8.0 games per year.
You can see above that in four of the past six seasons teams that finished with the most pass interference calls won the same amount or more games than the teams with the fewest pass interference penalties.
As I tracked different types of penalties, I noticed the same trend; those that come as a result of aggressive play (such as pass interference, roughing the passer and illegal contact) aren't correlated to losing football games. This is so astounding because these penalties are often the most harmful to a team.
Meanwhile, the mental mistakes, such as offsides and false starts, have a stronger effect on game outcomes despite being less costly in terms of down and distance. I really think this is because many aggressive penalties come along with many benefits, such as interceptions and sacks, whereas mental mistakes aren't the result of anything beneficial.
Obviously none of this means that penalties are a good thing. Ideally, you'd love for your team to play with optimal aggression and still limit penalties. The results indicate that cutting down on penalties at all costs, however, can be detrimental to your team success if it alters players' mindsets.
For the Cowboys, cutting down on penalties will obviously help the team's chances in 2012, but it's the mental mistakes that really need to go. Over the past four seasons, the Cowboys have finished with the eighth, third, second, and third-most false starts in the entire NFL, totaling the most total false starts over that time. Similarly, they've compiled the third, sixth, and tenth-most offsides penalties in the past three seasons, topping it off with a league-leading 15 offsides flags in 2008.
When you're watching your Dallas Cowboys in 2012, remember that not all penalties are created equal. If you see Tyron Smith or Doug Free move before the snap, go ahead and get on them. If Brandon Carr gets flagged for a controversial pass interference call, however, keep in mind that, unless he was out of position, the style of play that forced that call is one that could very well lead to an interception later in the game.