Saturday, June 29, 2013

The Measure Of Defensive Greatness: Best Scoring Defenses In NFL History

Defining greatness is subjective. Different people value and emphasize different things. There have been some defensive squads in the NFL whose greatness was undeniable. For those titans of the gridiron, the debate becomes which were better, and how do defenses of one era compare to those of another? This series will attempt to shed light on those questions while also exploring how far this young and talented Seahawks defense is from joining the ranks of the truly elite.

Part I: Scoring Defense

The Purple People Eaters of the early 70s Minnesota Vikings were bad dudes

The Point of Points

There have been great secondaries, great defensive lines, and prolific thieves that collected opponent turnovers by the bushel. Every defense is ultimately measured by their ability to keep opponents off the scoreboard. Opponent scoring average is a great indicator, even if there are some flaws. Points scored on offensive turnovers or in special teams show up on opponents scoring average and have nothing to do with the defense. A terrible offense can put the defense in precarious situations where even a three-and-out series results in a field goal. Still, legendary defenses find a way to keep their opponents scoring down. The game has changed too much to rely solely on points allowed as the measure of a great scoring defense. We will explore some more nuanced approaches to figuring out which defenses were the best ever at keeping opponents off the scoreboard.

Note: Due to a variety of factors, the research for this series will only go back to 1960. If time allows, I will update with data from the 30s, 40s and 50s as well.

Start with scoring 

Despite the flaws, it makes sense to begin the search for the best scoring defense in NFL history by the amount of points allowed. NFL schedules changed over time, so absolute points allowed tells us less than points per game.

It comes as no surprise that the legendary defenses of the Pittsburgh Steelers from the 70s, the Minnesota Vikings from the late 60s and early 70s, the Chicago Bears of the 80s and more recent stalwarts from Baltimore and Tampa show up among the Top 30 scoring defense of all-time. But how do you compare defenses that played in such different eras? 

Injecting offense into defensive evaluations has a nice feature that allows us to see how many points teams scored, on average, per game in any given season. I expected to find a gradual increase in scoring over the years. I was wrong.

The 70s seemed to have great defenses and suspect offenses

There was plenty of scoring going on during the 60s. It has only been in the last few years that teams have approached the record set in 1961 of 23.1 points per game. There was a huge trough in the 70s, and again in the early 90s. Evaluating a great scoring defense without factoring in the state of scoring in the league that year would be incomplete, at best. 

One way to accomplish that is to figure out how varied scoring was among the teams in each given season (also known as standard deviation), and then figure out how much did each defense stand out from the norm. The following table lists those same Top 30 scoring defenses, except now the amount of points offenses were scoring per game that season is factored in. It is sorted by how many standard deviations the opponent scoring average was compared to the average amount of points teams were scoring in the league that season. The standard deviation was calculated by looking at the average points per game scored by each team in each season. This helps tell us how varied the offensive output was in that year. The smaller the standard deviation, the tighter the bunching of what offenses were averaging that year. 

No team better illustrates the importance of contextualizing defensive performance than the 1977 Atlanta Falcons. They own the bragging rights as the best scoring defense of the bunch, allowing only 9.2 points/game. Their accomplishment is less impressive when factoring in a historic low in scoring across the league that year. The average team scored 17.2 The Falcons were just about two standard deviations below the norm. That still registers as one of the great defensive seasons in history, but drops them 19 spots when comparing greatness to greatness. Other teams hurt by an overall lull in offense across the league were the vaunted 1976 Steelers, who dropped 14 spots, and the two other 1977 teams that show up on the list, the Los Angeles Rams (-17 spots) and Denver Broncos (-16 spots). 

Teams whose accomplishments were amplified included some modern era teams like the 2002 Bucs (+17) and the 1985 Bears (+16). Both jumped into the Top 10. Teams averaged more than four points more per game in 2002 than in 1977, and the Bucs allowed only three points more per game than the 1977 Falcons. Tampa also benefited in the rankings by a smaller standard deviation, meaning that more teams were bunched around that average score per game and that they were less likely to face a team with an offense far off the average. 

Other teams barely flinched when offensive output was factored in. The 1969 Vikings moved up one spot to the top. The 1971 Vikings moved up one spot as well, as did the 1971 Baltimore Colts and the 1973 Miami Dolphins.

Note that the first table listing absolute scoring defense leaders had six teams from the 70s, and only one team from after 1977 in the Top 10. The new table has a more varied Top 10 that includes three teams from the 60s, four from the 70s and three from the 80s and later.

Defensive Scoring Efficiency

There are other variables to consider when evaluating scoring defenses across the decades. Any Seahawks fan that watched the 1992 season can tell you the impact of terrible offense on a great defense. The best measure here would be how many points does a defense allow per possession, combined with looking at their effectiveness in the first seven or eight opponent possessions. An offense that keeps putting their defense on the field puts strain and wear on that defense that cannot be measured by absolute numbers. There do not appear to be statistics about possessions that date back far enough to drill-down there. Instead, we can look at the number of opponent plays and the amount of points per play these defenses allowed. A defense can be at fault for yielding more plays, so there are some flaws here, but it is still instructive.

We are back to seeing a 70s-dominated Top 10, but there are still some insights to be gained. The Dolphins defenses drop to the bottom of the list. they were barely on the field in those two seasons, helped by an offense that finished 4th in scoring in 1971 and 1st in scoring in 1972. It is also interesting when comparing two teams of the same era. The 1985 Bears defense is one of the most famous in history, but the 1986 Bears defense was better in every way opponent scoring has been analyzed. Here, we see the 1986 team was on the field for far more plays, but still managed to allow far fewer points per play. 


That 1985 Bears defense will always be the one people remember because they ended the season with a Super Bowl ring. At each point in this series, we will examine the relationship of various types of defensive strength to championships. In this case, 16 of the Top 30 scoring defenses in history made the Championship game (not always the Super Bowl), with 12 coming away with a ring. 

The 2012 Seattle Seahawks

Seattle led the NFL in scoring defense last season at 15.3 points/game. That was among the highest totals to lead the league in a given season. Again, context matters. The only time offenses averaged more points in a season than the 22.8 points/game they scored in 2012 was in 1965 when they averaged 23.1 in 1965. The top scoring defense in that season belonged to the Green Bay Packers, who allowed 16.0 points/game. 

They allowed 0.253 points per play, which does not place in this list of great defenses. There is plenty of improvement needed there to reach the next plateau.

The 2012 Seahawks defense was only 1.6 standard deviations below the league scoring average. That puts them in decent company among the Top 30 from this sample, but not exactly elite. It is going to be hard for any defense to be historically significant without holding opponents to less than 13.0 points per game. Either that, or offenses are going to have to continue their upward climb to where teams are averaging 24 or 25 points per game. 

Either way, this Seahawks defense has some ground to make up in the scoring category if they want to become one of the best in history, as opposed to just the best in any given season.

The Best Scoring Defense In History

Carl Eller, and the rest of the 1969 Purple People Eaters in Minnesota earn the title of best scoring defense in history. They finished top overall in relative scoring defense (accounting for offensive output that season), second in absolute points allowed per game at only 9.5, and were a very respectable 6th in points allowed per play. They topped it off with an NFL Championship,  before losing to the Chiefs in the Super Bowl. There may never be another team to put those kinds of defensive scoring credentials together again.

Tuesday, June 11, 2013

Jim Harbaugh Still Bitter

The Seahawks are cheaters, if you have not heard. Four of the ninety players on the roster have been suspended for PEDs. One of them, John Moffitt, had a prescription that was not properly registered, and was a rotational guard last season. Another, Winston Guy, played a total of 17 snaps in 2012. A third, Bruce Irvin, admitted to Adderall usage during the off-season which has absolutely no impact on performance during the year. And last, Brandon Browner, was suspended for four games last year when the Seahawks beat those four opponents by a total of 170-43. This success of this Seahawks team has about as much to do with performance-enhancing drugs as Jim Harbaugh's Super Bowl loss had to do with the refs. That did not stop Harbaugh from insinuating there is a Vast Northwest Conspiracy concealing the seedy underbelly of Seahawks football. 

Pete Carroll is the Russian trainer from Rocky IV shoving needles in the arm of every player, cackling maniacally behind closed doors while striking the Monty Burns, "Egggxcellent!" pose with his hands. Russell Wilson has to be juicing. How else could he play so well with such obvious physical limitations?   Don't even get me started on Jon Ryan and Clint Gresham. It would be convenient for Harbaugh if all that was true. He could sleep so much better knowing that cheating was the reason his team was humiliated 42-13 last year. Do not underestimate the impact of that game on Harbaugh's psyche. 

Not only was it the worst loss (-29 points) of Harbaugh's NFL coaching career, but it was his worst loss since September of 2007 when his Stanford Cardinal lost to Arizona State 41-3. Harbaugh had also dominated Carroll. He had become so accustomed to beating Carroll that he had grown even more smug than usual after the 49ers squeaked by the Seahawks in San Francisco. He infamously taunted the Seahawks bus after that game, honking his horn and waving. This is a man with a god complex. He either wins, or somebody cheated. Players took PEDs. Referees missed a call. Someone else is obviously to blame, because it clearly is not his fault.

In many ways, it is a shame that Harbaugh is such petty and petulant man. He is a brilliant coach, who has his accomplishments tainted by his ego and immaturity. Pride, envy and wrath are all deadly sins. Any or all of them could be Harbaugh's downfall. 

Without them, he very well might be able to focus his attention on figuring out what his team did that allowed the Seahawks to rush for more yards (176) in that game than the 49ers had given up during his tenure. It was the most points allowed since he took over as coach. His team only had six points until a garbage time touchdown late in the fourth quarter. Seattle's special teams had scored more points than Harbaugh's offense up to that point. Games like that cause a psychotic break with a guy like Harbaugh. His reality will not allow the events that transpired that evening to be true. He will continue to grasp at straws to explain how it happened, and will fully expect to march into Seattle on the NFL's second week and win. 

Another Seattle victory would be send him spinning. Another Seattle blowout could lead to some time in a well-padded room. You cannot entirely fault Harbaugh for fighting the inception of the thought that the Seahawks may be the best team in football. Nearly everyone outside of Seattle, and many people in Seattle, still are struggling to accept the certain quality of the team practicing down in Renton. Seahawks and Super Bowl are not often uttered in the same sentence. They are now. Should you find yourself at a victory parade in early February, be sure to keep your eye out for a man muttering to himself about PEDs and cheating. It is likely to be the coach that recently got his ass kicked again by the Seattle Seahawks.

Friday, June 7, 2013

What A Healthy Walter Thurmond Would Mean

NFL off-seasons are chock full of paper tigers. Players that appear ready to burst onto the NFL scene, based on pad-less OTA practices and coaches comments. Then, the season comes, and it almost seems as if the coaches, the player and the media turn toward the fans in unison and say, "Gotcha!" The promise turns to disappointment and even a little bitterness for those that feel duped. One would think fans would eventually wise up to this repeated pattern, but, as Pavlov showed us, all you need is a little intermittent reinforcement to cause dogs--or football fans--to ignore the lessons of history. One player that fulfills the promise is enough to keep hope alive. Walter Thurmond represents a legitimate threat to make all Seahawks fans patsies again. He could be that one guy that lives up to the off-season hype, and leaves the 12th man vulnerable to the next dozen posers.

Thurmond has long been a favorite of mine, but ironically, his one healthy season was the nadir of my appreciation for his talents. He did not miss a game his rookie season, but Roy Lewis had outplayed him and earned a spot on the depth chart above Thurmond. It was not until he stepped in for an injured Marcus Trufant during his sophomore season that Thurmond's immense talent started translating to on-field excellence. Go back and watch the game in New York against the Giants from 2011. Thurmond blanketed receivers all over the field. Vertical patterns, crossing routes, digs, outs, it did not matter where the receiver was running because Thurmond was in his hip pocket. He proved he could slide inside or play on the edge. He was strong enough to play larger receivers and fast enough to stay with shifty ones.

His injury during the Browns game was tragic. Yes, it allowed Richard Sherman to emerge as an All-Pro corner, but it robbed the team of a player that may equal Sherman's talent. Yes, Thurmond is that good. He is also the only corner on the roster that can play any corner position. His 2013 season will be among the most intriguing, both because of the significance it has for Thurmond as a player and because of the possible quandary the Seahawks front office could face next off-season when he, Antoine Winfield, and Brandon Browner become free agents.

If you were John Schneider, and you wanted to make a decision about which corner to re-sign, what would you want to see in order to make the most informed choice? Browner is largely a known quantity at this point. He will also be 30 after this season. Antoine Winfield is also a known quantity and will be 36 next year. The guy who is least proven is Thurmond, at age 25. Schneider needs to see Thurmond play. Set aside injury for a moment, since it is obvious Thurmond will not garner much interest if he sustains another serious injury. When I say they need to see Thurmond play, I am talking about earning playing time.

Sherman is a fixture at one corner. There are no other fixtures. Browner is a Pro Bowl corner with a unique physical presence. Winfield is possibly the best nickel corner in all of the NFL and took less money to come play in Seattle. Both could lose playing time to a healthy Thurmond, and possibly even fall behind him in the depth chart. This is possibly the truest test of Carroll's competition mantra.

Sure, Russell Wilson beat out the higher-priced Matt Flynn at quarterback last year, but there was no established starter. If Carroll truly wants to win forever, younger players like Thurmond need to be given every opportunity to unseat established veteran starters. That's not to say Thurmond should be given any edge due to age, but neither should he be held back due to another player's reputation. The best player should play, period.

Browner is one my personal favorites on this team. I love what he brings in terms of toughness, and even enjoy his occasional forays past the legal limits of physical play (don't try to play tough guy Greg Jennings). Judging his value on the open market is difficult. He will be older, but very well could have two Pro Bowls in three years to his name and catch the eye of some team that is swept up in the Carroll-induced gold rush for tall corners. Seattle will not overpay for his services. They have Sherman, Earl Thomas and Kam Chancellor that require top dollar. The other corner cannot be a highly-paid player.

Thurmond is a wildcard. He may command more money than Browner as a free agent even if his pedigree comes nowhere close. He is younger and more scheme-diverse than Browner. There is a chance that he becomes one of the bigger free agent targets next year if he manages to stay healthy. That is why the wise move for the Seahawks would be to sign him to an extension right now.

The Seahawks face the real possibility of losing two-thirds of their starting corner trio next year in Browner and Winfield. They could choose to extend Browner, but his age and accomplishments will make that difficult, as he will want to get his big pay day. Thurmond can play outside and inside, and may be better than either of the other two players. He and his agent know they risk a disaster in free agency if Thurmond gets hurt again, so they should be open to some guaranteed money over 1-2 years that would allow Thurmond to hit the market again when he is still young enough to get a big deal. The Seahawks would roll the dice that they were locking in a Pro Bowl-caliber corner at a bargain basement price. Even if Thurmond got injured again, the length and price of the deal would not hamstring the team.

How that would play in the locker room is a separate question. It would be a clear sign that the team planned to move on from Browner, a guy that has earned his money. Still, it would be the wise business move to manage risk to the roster. The other options would be to extend Browner, which is not likely, or to wait and see how things turn out after the season which could very well result in the loss of all three players. Yes, there is depth in Byron Maxwell, Jeremy Lane, Tharold Simon and others, but none of them have come close to showing the sort of ability that Thurmond has.

These are the questions the front office must ponder while fans and media are busy salivating over OTA all-stars. A position of immense depth for 2013 faces risk in 2014 that could be mitigated by a savvy, proactive extension. The Seahawks should act fast, as Thurmond's play on the field may quickly remove any leverage the front office has.