In 2012, the Indianapolis Colts wildly outperformed preseason expectations on their way to an 11-5 record and a playoff berth. Not coincidentally, they also led the NFL in penalty-yard differential; their opponents were penalized 407 yards more than they were throughout the course of the year.
Prior to the season, I published the following graph as evidence that, as we’d expect, excessive penalties affect team performance in a big way.
In 2012, the effects were greater than ever before with successful teams like the Colts, Falcons, Broncos, Patriots and Packers ranked in the top 10 in penalty-yard differential and poor squads like the Rams, Lions, Bills, Jaguars and, yes, your Dallas Cowboys all ranked in the bottom 10 in penalty-yard differential. Overall, top-10 teams in terms of penalty yards won an average of 9.6 games, while the bottom 10 teams averaged only 7.1 wins.
This year wasn’t an aberration for Dallas, either. Over the past six seasons, the Cowboys have ranked in the bottom six in the NFL each year in total penalties. That’s six straight seasons ranked 27th or worse! If there’s ever been evidence that penalties remain relatively stable from year to year (they do), the Cowboys are it.
It’s pretty remarkable that the Cowboys have been able to overcome the penalties to post a 55-41 record since 2007, but it’s still frustrating to wonder what could have been. Well, by tracking the situations in which the Cowboys’ penalties have come over the past six years, we can calculate how many wins they’ve forfeited over that time – exactly what “could have been.” Certain penalties, say an offsides penalty on third-and-1, have affected the Cowboys’ chances of winning more than others. All told, the ’Boys have “lost” just under three extra games due solely to penalties, or about half a game per year. Put another way, Dallas has suffered a 50 percent chance of losing an extra game each season simply because of penalties.
Not all penalties are created equal, however. When you think about which penalties are most detrimental to a team, you probably consider defensive pass interference, roughing the passer and so on. Those sorts of penalties obviously hurt the most at the time that they occur, but believe it or not, they aren’t correlated with team losses. Actually, teams that have committed the most defensive pass interference penalties over the past decade have actually won more games than those penalized the least.
On the flip side, many of the penalties that seem much less harmful than pass interference, such as false starts and offsides, are actually more strongly correlated with losing. But why? The answer, it seems, is that the aggressive style of play that leads to certain types of penalties has lots of benefits, too. The same ferocity that might result in a 
Meanwhile, there’s no silver lining with many other types of penalties, especially those before the snap. Such mental mistakes are the type that can theoretically be avoided; they’re self-inflicted wounds that don’t benefit a team in any way. Unfortunately, the Cowboys have been among the league-leaders in pre-snap penalties for years, ranking no better than 20th in any of the past four seasons. It culminated in 58 pre-snap penalties per game in 2012, the second-worst mark in the NFL, so things don’t appear to be improving.
Look, there’s obviously no doubt that penalties are extremely detrimental to a team’s ability to win. The Cowboys’ penchant for committing excessive penalties has obviously set them back in recent years, but that doesn’t mean their goal should be decreasing their penalty rate at all costs.
Instead, they need to focus on limiting the pre-snap penalties, those that don’t come with any indirect benefits, while accepting a handful of the post-snap penalties that are the inevitable result of playing aggressive football.
