Top 10 Greatest Defenses

[Lumiere]

Football Outsiders posted their top 30 super greatest defenses of the past 30 years a little while back. Unfortunately, I don't really know exactly what their proprietary metric "DVOA" seeks to measure...so I thought it would be interesting to post my own top 10 using a different set of metrics.

This is a long read ~ grab a comfy chair.

Attempting to objectively evaluate a team’s defense means attempting to uncouple its overall performance with a team’s offense. Average opponent starting field position and total number of drives are influenced by the effectiveness of a team’s offense. The average offensive strength of a team’s opponents and overall strength of schedule will also influence a defense’s performance.

Imagine two identical defenses, both extremely strong. But one defense is attached to a very strong offense (team-A), the other to a very weak offense (team-B). Now imagine playing a very strong team with an elite offense and solid defense (team-C). Team-A beats team-C by a blowout, giving up only three points with a dominant offensive showing, and posting a defensive yards per play of 3.8 - truly a spectacular defensive performance. Meanwhile, in an identical situation, team-B also beats team-C, but by a field goal in a very close game, giving up 17 points. Team-B's offense was terrible throwing two interceptions and losing two fumbles, while repeatedly going three and out, and giving the opposing offense a short field on many occasions. In the end, team-B also posted a defensive yards per play of 3.8...but with a very different score. Which defense actually did more, or did they play equally? Which defense was better rested? How do you grade the better defense given the circumstances? Too often in my opinion, the offensive contributions are completely ignored when a great defense hangs a bunch of zeros on its competition. Or the lack of offensive contribution completely excluded when a great defense barely wins a game against a strong opponent with a negative turnover differential and only a handful of first downs.

Trying to evaluate a defense’s true strength would require primarily focusing on defensive yards per play (YD/P), normalized by its differential of median opponent offensive strength, with the same normalization applied to defensive turnovers, and average plays per TD scored. Normalizing the numbers by measure of the average strength of opponent will reflect the percentage of domination over opponent, which would be more accurate than normalizing against league average (which would too heavily reward or punish a team with an easy or difficult schedule). An example of how this would look…consider a team with a very poor offense that only faced off against top 10 offenses with a brutally difficult schedule. The overall defensive statistics of points allowed, total yardage (and even yards per play to a lesser extent), would be proportionally impacted by their own weak offense and the strong offense of their opponents. In this example, the greatest defense of all time may post very average looking numbers…but when you factor in the strength of offense faced and the differential of yardage, turnover, and play count per TD averages, the level of “greatness” is displayed in the percentage of domination over opponent.

If you were to attach a very strong defense to a very strong offense, and give that team a very easy schedule…it would likely set numerous defensive records. If you were to attach an exceptionally strong defense to a terrible offense, and give that team a very difficult schedule, it would likely set no defensive records, and even struggle to win games. The 1991 Eagles are an approximate example of just such a situation – what would the degree of defensive dominance look like when weighted to the team’s opponents, strength of schedule, and while factoring in the lack of offensive contribution? It would look like the 1991 Eagles…which were statistically the most dominate defense in modern NFL history by measure of its domination over opponent. If the 1991 Eagles had the 2000 Ravens schedule or the 1985 Bears offense, the strength of this defense would be far more apparent…but it is still visible in the numbers.

The primary metrics used in this analysis and their explanation:

Regular season:

YD/P opponent offensive differential = the percent change of the team’s average defensive YD/P over the average offensive YD/P of all opponents faced. This will display a truer measure of defensive YD/P dominance (or delta) by factoring in the offensive strength of all opponents faced. A higher number reveals a greater level of dominance – example, 2015 Broncos 4.4 YD/P grades far higher than the 2000 Ravens 4.3 YD/P due to average offensive YD/P of opponents faced.

Defensive turnover (TO) opponent offensive differential = the percent change of the team’s average defensive turnovers per game over the average offensive turnovers per game of all opponents faced. This normalizes the defensive turnover amount by likelihood of offensive turnover of opponents. A higher number reveals a greater level of dominance in defensive turnovers.

Plays per TD opponent variance – due to the lack of available red zone data from the early 90’s and prior, this is an approximation of “scoring resistance” with the differential based on average opponent plays per TD. It is the percent difference of the defended average number of plays per TD, compared to the opponent’s offensive plays per TD as an average. Being that it is scoring based, it is skewered by offensive performance to some degree (the three lowest ranking teams by this metric also had the three worst offenses - including the greatest defense of all time)…however, being that the offensive strength is also graded, provides just a bit of clarity.

Playoffs:

YD/P and points scored opponent offensive differential - or playoff dominance. Dominating in the playoffs is a traditional staple that defines a truly great defense. Did it play against elite offenses? Did it dominate against elite offenses? A defense that dominated in the regular season, but produces less stellar numbers in the playoffs is graded accordingly, with regular season grades averaged with playoff grades. The 2008 Steelers are an example of a fiercely dominant regular season defense, that was far less dominant in the playoffs. This metric is the playoff YD/P and points allowed compared against the opponent’s regular season offensive YD/P and points scored per game. I chose to consider points for two reasons: a) it’s a small sampling of crucially important games, and b) the legacy of a defense’s performance in the playoffs is irreparably tied to points. This metric shows the degree (or percent) of playoff dominance over the opponents faced. I was honestly surprised that we ranked ahead of the 2013 Seahawks in this metric. If we just considered the points scored/average, the Seahawks ranked above us (but not by much). If we just considered yards per play, we ranked above them (but not by much). Yards and points considered jointly, we edged them out by the slimmest of margin (though in fairness, Super Bowl XLVIII probably should have been a shut out, and reminded me of the 85 Bears beat down of the Patriots in Super Bowl XX…giving up a touchdown only in garbage time with the game already well decided), but the stats are what they are. The bulk of their rating came from the destruction of the Broncos’ #1 offense in Super Bowl XLVIII.

Secondary metrics are:

Strength of schedule (as a measure of opponent win percentage), lack of offense by measure of average offensive league ranking in points scored, yards, offensive turnovers, and time of possession (if known), as an opponent forced to play “catch up,” and/or possessing a well-rested defense, and/or advantageous opponent starting field position, is surely of significant defensive benefit. Whether team won the Super Bowl, and if so, the strength of the playoff teams (as measured by SRS or "simple rating system" utilized by pro-football-reference.com, and the degree of defensive dominance over those playoff teams (factoring in opponent offensive strength).

Every defense on this list is superb…and I think “ranking” them does those at the bottom a disservice. Each defense had unique challenges, any of which, could have radically altered the fate of the team. Some defenses had the support of a great offense, while others had an easy or difficult schedule. There is no right or wrong…just discussion…and the opinion that birthed this blathering nonsense. There are plenty of other notable mentions, and not so conspicuously missing from this list are many great defenses from the early 1970’s. My only reasons for excluding those is that I was more interested in the focal point toward the more “modern” game. In a greater list, many 70’s (and 60's) defenses should surely be included, rather than just the two that are.

Lastly, defining “greatness” is purely subjective…and it’s actually quite easy to cherry pick statistics to form a favored outcome. The final listing is not purely formulaic, but rather I used the numbers as guidelines in deciding. I tried to view this as objectively as I could – based on the metrics chosen, this is how I would rank the all-time greats. <Continued next post>

[Lumiere]

1. 1991 Eagles

The `91 Eagles defense is so ridiculously over the top, given both the strength of schedule and horrid offense…it’s just jaw-dropping to even ponder. For a defense that had so little help on the other side of the ball, they posted a staggering 3.9 total defensive YD/P, and were #1 in defensive takeaways. Even more impressive is the YD/P opponent differential of 23.68% which ranked 1st of all teams, and their defensive turnover opponent differential of 56.25%, ranked 2nd. They accomplished this with the hardest schedule of all teams listed and the weakest offense by far. In addition, they had the hardest ranking of average strength of opposing offense at 2.2% over league average in yards per play. The second best rushing defense in modern NFL history, and arguably the second best passing defense. Buddy Ryan somehow improved upon the `85 Bears, but without any offense, managed a 10 – 6 record in a difficult division. Arguably the greatest defense of all time was sadly wasted away when they lost Randall Cunningham in week 1, with no plan-B.

2. 1985 Bears

Just about every team on this list was very difficult to place due to the very nature of this grading. The intent (which is mathematically challenging) was to evaluate a "true strength" of defense, ignoring offensive contribution where feasible. The 1985 Bears possessed the best offense of all teams listed, making this challenge especially difficult. They posted a 4.4 defensive YD/P, which in 1985 wasn't particularly spectacular (the 2015 Broncos posted a far more impressive 4.4 in an era of extreme yardage). Their YD/P opponent differential was 12.52% which actually ranked 8th of the 10 teams. So teams could actually move the ball against this defense...but scoring on them was difficult. Without access to red zone data, I can only surmise that their low point total was due to an outstanding red zone defense, and an offense that dictated time of possession and chewed up clock. Their regular season TD variance was 52.36% which was good enough for 7th place, but they defended a minimal play count relative to league average. Their defensive turnover opponent differential was 32.55% ranking fifth and they led the league in defensive takeaways. In the regular season, I would actually rank several teams above the 1985 Bears, based on the metrics utilized. Where the Bears defense cemented its legacy was in the postseason. In the playoffs, their defensive YD/P was closer to two - which effectively rendered them a brick wall. Their playoff differential over opponent YD/P and point averages was an astonishing 63.11%. To put this statistic into perspective, a rating of 100% dominance means that their playoff opponents averaged zero yards and zero points. 63.11% is mind boggling. The 1985 Bears’ extreme dominance in the playoffs bumped them ahead of the #3 team, for second best defense in modern history.

I consider this team the best “all-around football team” of all time (based in the era that they played, as Buddy's 46 would not work exclusively in today’s league), by measure of their incredible statistics. They were only bested by a brilliant Dan Marino, on the road, with their backup QB. It took a stout Miami offensive line and Marino’s legendary quick release and downfield accuracy to even afford a chance. Also on display were Miami’s use of three wide receiver sets, not often used in 1985…as a weakness of Buddy’s 46 defense was a spread offense. But even still, Marino got plastered often, all game long…and is probably lucky to have not been carted off the field.

3. 2002 Buccaneers

The 2002 Bucs were an astonishing defense. Considered by many to be the greatest passing defense in modern NFL history, they posted a YD/P opponent differential of 17.16 (ranked 6th). However, the one stat that stands out to me is their plays per TD variance differential of 84.74% despite the fact that they were not equipped with a top flight offense. That's an astonishing number and just behind the `76 Steelers. Their offense graded out with a league average rating of 13.25 (out of 32 teams), with a slightly easier but comparable strength of schedule to the `85 Bears. In the playoffs they posted a monster 35.6% differential over opponent YD/P and point averages, over respectable opponents (including two top five offenses), which ranks third of the teams listed. I believe the 2002 Bucs are generally an underrated defense in most "greatest ever" lists. The Steel Curtain inspired Tampa-2 coverage shell was devastating with this roster (and surprisingly stout against the run) – I list them as the third greatest defense.

4. 2015 Broncos

The 2015 Broncos were by far, the most difficult team to grade due to a myriad of reasons:

a) They had arguably the worst offense of any team to ever win the Super Bowl.

b) They had a difficult strength of schedule (2nd only behind the `91 Eagles on this list) and faced an average regular season offense rated at 1.64% below league average (compare this to the 4% below average `13 Seahawks or 6.67% below average 2000 Ravens).

c) Assessing playoff dominance factoring in offensive ineptitude and strength of opponent.

The 2015 Broncos posted the fourth best YD/P opponent differential of 18.67% (with a raw 4.4 YD/P), of all teams listed, but ranked 7th in defensive turnover opponent differential with 22.46%. Where they lose ground is the TD variance differential with 30.55% (ranked 10th), which corresponds to a 20th ranked red zone defense in TD percentage according to Football Outsiders. The 2015 Broncos ranked first in preventing red zone appearances, but 20th in touchdowns allowed. This was almost certainly aggravated by an offense that ranked near league worst in offensive turnovers and time of possession (average offensive league ranking was 22.25 out of 32 teams). Only the `91 Eagles had a worse offense and harder schedule than the 2015 Broncos. Where the 2015 Broncos defense asserts its greatness was in the postseason. With the second highest SRS opponent average, the 2015 Broncos posted a 28.08% differential over opponent YD/P and point averages, against three top five offenses with the lowest graded offense of any Super Bowl winning team (defeating the #1 scoring offense in the Super Bowl while themselves gaining less than 200 yards of total offense, and still winning by two touchdowns). Averaging season and postseason...the 2015 Broncos placed at 4th best defense in modern history.

5. 2013 Seahawks

The 2013 Seahawks were also extremely difficult to evaluate based on the confines of the metrics chosen. Equipped with an offense that graded at 6.33 best in the league, makes their defensive accomplishments harder to position relative to other teams.

Their 4.4 defensive YD/P was the product of a 7th best 15.06% YD/P opponent differential of teams listed. Where they shined was defensive takeaways, posting the #1 turnover opponent differential of 56.41%, and a TD variance differential of 65.83% (4th best). In the playoffs, they had the highest opponent SRS average (on paper the most difficult average playoff opponent), and posted a 27.98% differential over opponent YD/P and point averages (which ranked fifth). I placed this team below the 2015 Broncos due to a 1.88% difference in regular season grading in favor of the 2013 Seahawks, and the Broncos posting a comparable level of playoff domination with significantly less offense. The two teams were very close in grading (averaged with both secondary metrics and playoff dominance was a difference of less than 1%) with the nod going to the Broncos due to lack of offense and strength of opponents.

Not factored in the grading, but just as a side note for consideration - I believe the strength of the 2013 Seahawks offense correlated with opposing teams taking more risks in the air than they otherwise would have, enabling their top ranked secondary to feast, and playing right into the core strength of their defense. They had just a bit of an easier strength of schedule based on opponent win percentage than the 2015 Broncos (which surprises many as the NFC West in 2013 was scary good), and faced an average offense that ranked 4.07% below league average - but that is factored into the differential values. In the end, the raw primary seasonal metrics were extraordinary, but the strength of their offense and of their opponents lands the 2013 Seahawks at #5. <Continued next post>

[Lumiere]

6. 2008 Steelers

The 2008 Steelers are generally a hugely underrated defense, and I can't help but feel like I'm slighting them a bit by placing them beneath the 2015 Broncos. Comparing the regular season statistics only, the 2008 Steelers narrowly bested the 2015 Broncos in all primary metrics (and were slightly below the Broncos in secondary metrics). Their 22.92% YD/P opponent differential is second only to the `91 Eagles, their turnover and TD variance differentials ranked sixth and eighth, respectively. They had a difficult strength of schedule, slightly easier but very comparable to the 2015 Broncos, but faced an average offense that ranked 4.53% below league average in offensive YD/P. They too, were an offensively challenged team with an average league ranking of 18.75 out of 32, with a slightly better offense than the `15 Broncos. When factoring in the playoffs, the 2015 Broncos were far more dominant against stronger opponents...resulting in the 2008 Steelers landing in sixth place. But make no mistake - with their strength of schedule and offensive malaise, this was an extraordinary defense that deserves far more praise than it gets.

7. 2000 Ravens

This is without question, perhaps the most controversial placement of any team on this list. In my opinion, the 2000 Ravens are one of the most overrated defenses in NFL history (which are often placed at #1 or #2 in a "greatest of all time" list). There is no denying that this was an historically good defense - they possessed the best rushing defense of all teams statistically (based on average). Where things get a little murky, however, is with their 5.3 passing YD/P with a very weak schedule (they had by far the weakest strength of schedule of all 10 teams listed, in addition to facing an average offense that ranked 6.67% below league average in YD/P), and without facing much of any “elite” quarterbacks. Of the 11 teams that they faced, the average net passing yardage per game of these 11 teams was 187…which was 9.6% below league average. This compounds the uncertainty of their YD/P opponent differential (or dominance over opponent's offense in defended yards per play) which was only 1.26% - by far the lowest of all 10 teams. So, their 4.3 defensive YD/P was only actually 1.26% better than the average offensive YD/P of their opponents (which ranked 6.67% below average on average). In my humble opinion...that's at least a little bit problematic when you have: a) the greatest rushing defense of all time, and b) you're facing off against the likes of quarterbacks: Jaime Martin, Akili Smith, Tim Couch, Kordell Stewart, Jay Fiedler (helped hand them their biggest loss of the season), Ryan Leaf, Troy Aikman in his final year, an aging Scott Mitchell, et al. In the playoffs, they faced: a Gus Frerotte and Jarious Jackson led Broncos team, Steve McNair (probably their greatest challenge), two quarters of Rich Gannon, and a Kerry Collins led Giants team in the Super Bowl.

The 2000 Titans actually had a better defensive YD/P than the 2000 Ravens, but a far less impressive turnover differential. Also, contrary to popular belief, the 2000 Ravens offense was not “terrible” as many claim, but rather marginally league average. When you factor the Ravens’ low offensive turnovers and top 10 time of possession, the 2015 Broncos offense was noticeably worse by comparison. Where the 2000 Ravens made their greatest mark was in the playoffs (like many of the greatest defenses). The Ravens absolutely dominated in the postseason, posting the second highest playoff differential over opponent YD/P and point averages with a mind numbing 56.58%. Whether good opponent or bad opponent...that is historically devastating.

I list them at #7 due to the tremendous greatness of their rushing defense, and their absolute domination in the playoffs. However, I consider them the greatest benefactor of their schedule from an historical ranking standpoint, and the offensive weakness of their opposition should exclude them from any top five listing.

8. 1976 Steelers

Listing this defense at #8 is genuinely painful, as their regular season statistics are truly phenomenal. They faced an average offense that rated 1.96% above league average and posted an 18.98% YD/P opponent differential (ranked 3rd and just slightly better than the 2015 Broncos but behind the 2008 Steelers), a 38.82% defensive turnover opponent differential (ranked 4th), and the most jaw-dropping statistic, a 91.40% plays per TD opponent variance...which makes this the hardest defense to score on of the bunch. But, like most high ranking plays per TD variance statistics, it has a corresponding highly rated offense. The 1976 Steelers had the #1 league rushing attack in dual 1000 yard rushers Franco Harris and Rocky Bleier. Overall they rated 7th in league average offensive ranking, with a relatively poor passing game dragging them down. The `76 Steelers ranked #2 in the regular season statistics grading (behind the `91 Eagles), but the gap between the two teams was wide at nearly 10%. Because of this, and their loss to the Raiders in the conference championship after losing both of their 1000+ yard running backs in the divisional round, I had to place this defense below the 2008 Steelers (who themselves ranked third in regular season grading and went on to win the Super Bowl with minimal offense)...and placing the 2000 Ravens at 9th seemed ridiculous.

Historically, this is widely considered the greatest defense of all time...if we were only interested in points scored and excluded all offensive metrics, I would tend to agree. Of course, in that listing, the `91 Eagles wouldn’t crack the top 50. We’re using different metrics, so the `76 Steelers get bumped down a bit. The main reasons why they are placing 8th here is due to the performance of the `91 Eagles, coupled with the fact that this ranking is generally combining regular season and postseason performance, and additional scrutinization applied to the stronger offensive teams (e.g., the `76 Steelers). An exception to average the regular season with the playoffs was made for the `91 Eagles due to the otherworldly strength of their defense, combined with a difficult schedule, and total lack of offense. The `76 Steelers on the other hand, were a complete team that faltered for the first five weeks and put themselves in a hole...then lost Terry Bradshaw in week five. Their defense then went on the greatest nine week scoring run in NFL history, while their rushing offense ranked #1 in the league. Once in the playoffs, they were stout against Baltimore's #1 offense, but lost both Franco Harris and Rocky Bleier, who were essentially the heart of their offense. In the conference championship, without their dominant ground game, they couldn't keep the Raiders off the field and their defense faltered in stopping the run. They kept Ken Stabler largely in check, but he did toss two touchdowns, and they lost by a score of 24 - 7.

This was a ferocious defense whose astronomical scoring resistance was certainly aided by the #1 rushing offense in the league...but their numbers were truly historic.

9. 1973 Dolphins

On the heels of the only perfect Super Bowl winning season in NFL history, the 1973 Dolphins emerged with arguably a better team….and facing a much harder schedule. Miami’s “No Name Defense” posted a stunning 18.50% YD/P opponent differential (ranked 5th of the 10 teams), and the 3rd best plays per TD opponent variance of 74.14%. They faced an average offense that ranked 1.30% below average and were tied with the 2013 Seahawks with an offense that ranked 6.33 out of 28 teams. Their playoff dominance over opponent YD/P and scoring averages was graded at 28.87% (just slightly higher than the 2015 Broncos). But with a formidable offense and average strength of schedule (and negative rated defensive opponent turnover differential), the `73 Dolphins found themselves at #9.

10. 1990 Giants

The 1990 Giants put together an amazing year defensively. Led by Lawrence Taylor (and coordinated by Bill Belichick), they posted a 10.16% YD/P opponent differential (ranked 9th), and ranked just ahead of the 2015 Broncos in raw averaged primary regular season metrics. They had the sixth hardest strength of schedule of the teams listed, and faced an average offense that ranked 0.4% above league average. With the 11th ranked offense (and #1 ranking in the league for fewest offensive turnovers), they were renowned for their ball control and outstanding time of possession (setting a Super Bowl TOP record of 40:33). In the playoffs, they posted a 21.98% differential over opponent YD/P and point averages (ranking 7th of the 10 teams). They defeated the #1 scoring offense (the no huddle Buffalo Bills), when Bills kicker Scott Norwood sent a 47 yard game winning kick wide right in the closing seconds. The 1990 Giants placed 10th overall on this list, and are certainly one of the greatest defenses ever.

`Ol Bill’s defensive game plan for Super Bowl XXV is currently on display at the NFL Hall of Fame.

[Rastic]

Nice write up. Thanks for taking the time to give your personal take. :thumb:
Gotta spread it.

[HUMCALC]

I'd put BAL higher than those teams that had better offenses, like SEA & DEN. Sure there #s aren't as good, but they had less to work with

[Dennis.1960]

There are plenty of other notable mentions, and not so conspicuously missing from this list are many great defenses from the early 1970’s. My only reasons for excluding those is that I was more interested in the focal point toward the more “modern” game. In a greater list, many 70’s (and 60's) defenses should surely be included, rather than just the two that are.

Very interesting analysis and a great read

Growing up as a Vikings fan, I was wondering where one of those brutal Vikings "Purple People Eater" D's of the '69 to '76 seasons would rank...especially the '71 team where Alan Page became the 1st defensive player to ever win the MVP

[Peanut]

Very impressive, Lumiere. Thanks for taking the time to do this.

A lot to take in. I need to read it again.

[Lumiere]

I'd put BAL higher than those teams that had better offenses, like SEA & DEN. Sure there #s aren't as good, but they had less to work with

The 2000 Ravens genuinely surprised me. I knew that they had an easy schedule, but I had no idea that they faced such weak passing offenses...and their passing defense was one of the weakest of the 10 teams listed. Looking at the numbers, I was shocked to see that they fared 2.6% worse than the average opponent of their opponent in net passing yardage with league average attempts…it’s not like they dominated against inferior passing offenses…but, to the contrary, inferior passing offenses fared 2.6% better against the Ravens. I just couldn't place this team in the top-5 because of those numbers.

Due to their passing defense, I honestly believe that if they faced league average opponents, their overall defensive statistics would not have been historic, and they're likely not listed in any top 10 list (if they could even make the playoffs at all).

But, that said...their performance in the postseason was storybook, and second only to the 85 Bears.

[Lumiere]

Very interesting analysis and a great read

Growing up as a Vikings fan, I was wondering where one of those brutal Vikings "Purple People Eater" D's of the '69 to '76 seasons would rank...especially the '71 team where Alan Page became the 1st defensive player to ever win the MVP

Thanks!

When scrutinized through a fine toothed comb, I would love to see where all of those great defenses rank. The numbers gathering is time intensive...but it would be a fun project.

Very impressive, Lumiere. Thanks for taking the time to do this.

A lot to take in. I need to read it again.

Thanks, Peanut.

[CanDB]

Wow.....just caught this one! Excellent work my friend! I thought it was a link of some sort, which would have been good enough, but dude, you went the extra proverbial mile!!! I am always impressed when folks here put in the time and effort, to go that extra distance.

I have to read it again, which is a sign that someone put in a ton of work. My initial thoughts are, I was a little surprised that Philly was #1...but not because they weren't great, but because of all the other hype for the teams we typically hear about. Of course a number of teams come to mind, without thinking too hard - The Steel Curtain (more than once), The Bears, Giants, Ravens, Seahawks, Bucs and yes, our gang. And initially I had the late Steelers Ds higher than the 08 version. Heck that era had so many HoF'ers, it was almost a crime.

But I am going in deeper with your analysis, because any list is a good list if some thought is put into it.

Thx bud!!! Sorry I was so late to the party!!

[CanDB]

So pal, how did you narrow down these teams from the larger list of potential top 10 teams? You are talking a lot of stats, and I assume you began with an established list (was it the top 30 you mentioned?...sorry if I missed that), because otherwise this would take a goofus like me weeks to compile....maybe longer!!

Even so, the type of stats you use must have taken some time to capture. Was there an effective way to find them all? Even if so, I commend you for defining your parameters, creating a list of great teams to compare, comparing all stats against one another, and then coming up with your assessment. I know how hard this is, given some simpler studies I have done here. It can take hours/days.

Finally....did our Orange Crush teams get even close to the top teams, or were they really good but not great?


Again.....good on you, bro!!!:thumb:

[Lumiere]

Wow.....just caught this one! Excellent work my friend! I thought it was a link of some sort, which would have been good enough, but dude, you went the extra proverbial mile!!! I am always impressed when folks here put in the time and effort, to go that extra distance.

I have to read it again, which is a sign that someone put in a ton of work. My initial thoughts are, I was a little surprised that Philly was #1...but not because they weren't great, but because of all the other hype for the teams we typically hear about. Of course a number of teams come to mind, without thinking too hard - The Steel Curtain (more than once), The Bears, Giants, Ravens, Seahawks, Bucs and yes, our gang. And initially I had the late Steelers Ds higher than the 08 version. Heck that era had so many HoF'ers, it was almost a crime.

But I am going in deeper with your analysis, because any list is a good list if some thought is put into it.

Thx bud!!! Sorry I was so late to the party!!

Thanks, bud! I just got sick and tired of reading "greatest ever" defense lists that I felt completely ignored offense (and special teams) and strength of opponent. Some of my favorites placed the 2000 Ravens as the #1 defense. In these, while acknowledging their easy schedule, it was completely dismissed as a viable metric due to the fact that, "the team doesn't control who their opponents are." Ok, so by that logic, a world class sprinter sets a new world record while running slightly downhill and with the wind to their back. It's not the sprinter's fault that that just so happens to be the track. Meanwhile, another sprinter ties a previous world record while running slightly uphill and with the wind to their face. In my opinion, strength of opponent is a critical metric especially when "historic" statistics are concerned. The NFL does not possess 100% parity...there are discrepancies amongst teams.

What also stands out to me, is virtually all great scoring defenses were tied to an above average offense...the correlation was plainly obvious. A defense becomes marginalized or glorified based on offensive situations that it has no control over. The roots of this project were to attempt to gleam some semblance of a “true strength” of defense. Of course, all of this is mostly just conjecture...it is the mathematical equivalent of a "what if" scenario. But, I thought it was still interesting – it was fun swimming through the numbers.

The `91 Eagles were a freak show of a defense. With these metrics they were far and away #1…and it really wasn’t even close. They just had no offense, and so are an afterthought in most rankings. I think they're deserving of the top spot, in my humble opinion.

[Lumiere]

So pal, how did you narrow down these teams from the larger list of potential top 10 teams? You are talking a lot of stats, and I assume you began with an established list (was it the top 30 you mentioned?...sorry if I missed that), because otherwise this would take a goofus like me weeks to compile....maybe longer!!

Even so, the type of stats you use must have taken some time to capture. Was there an effective way to find them all? Even if so, I commend you for defining your parameters, creating a list of great teams to compare, comparing all stats against one another, and then coming up with your assessment. I know how hard this is, given some simpler studies I have done here. It can take hours/days.

Finally....did our Orange Crush teams get even close to the top teams, or were they really good but not great?


Again.....good on you, bro!!!:thumb:

They key starting focal point was league leading yards per play defended and elite scoring defenses. I also perused many lists online to whittle down the pool to just 10 teams…I ended up swapping one out halfway through – the 1975 Rams for the 1990 Giants (due to the `75 Rams’ schedule which was even weaker than the 2000 Ravens). I couldn’t analyze any other defenses due to time constraints.

Of the teams listed, every opponent faced had to have data gathering, as the normalization was against opponent averages, not league averages. To try to do this with every strong defense going back to the 60’s/70's would take months.

I actually started this in early June and spent about a month working on it (just for 10 teams). Though in my defense, I’m not a professional data miner! Data gathering was on pro football reference, with pages and pages of spreadsheets. I had fun working on it because I was genuinely interested in the results…even if it is somewhat arbitrary.

I would love to be able to put every great defense through this filtration, but it’s just a bit time consuming. It would be cool to know though…so many great defenses in the bygone eras.

[mile high mad man]

Thanks for sharing ! I really enjoyed the read .

[CanDB]

They key starting focal point was league leading yards per play defended and elite scoring defenses. I also perused many lists online to whittle down the pool to just 10 teams…I ended up swapping one out halfway through – the 1975 Rams for the 1990 Giants (due to the `75 Rams’ schedule which was even weaker than the 2000 Ravens). I couldn’t analyze any other defenses due to time constraints.

Of the teams listed, every opponent faced had to have data gathering, as the normalization was against opponent averages, not league averages. To try to do this with every strong defense going back to the 60’s/70's would take months.

I actually started this in early June and spent about a month working on it (just for 10 teams). Though in my defense, I’m not a professional data miner! Data gathering was on pro football reference, with pages and pages of spreadsheets. I had fun working on it because I was genuinely interested in the results…even if it is somewhat arbitrary.

I would love to be able to put every great defense through this filtration, but it’s just a bit time consuming. It would be cool to know though…so many great defenses in the bygone eras.

Interesting!! I think I know what you went through, a ton of work, but a passion for what you were doing. Passion trumps work! In fact, I always say that my favourite jobs, the ones I was most passionate about, did not seem like work......ha ha, to a point.

And yes, what I would give to have more data mining savvy.

Again, excellent study. And you are right, some of this ends up being subjective, so the more objective we can be, the better. One thing for sure, you have quenched my thirst for reading up a little on The Eagles, given I do not remember many of the players. I am sure that once I look up the roster, it will all come back in a second.

Whether you and I, or you and others agree on the top 10, your process and your effort are to be commended! And I want this thread to go for a while longer, because it is important that we reward effort. I know what it is like to spend days on a thread and have it bi passed quickly due to the attention going to other places. That's all part of the game here, but I do look for threads such as this to give my stamp of approval....as long as I am aware. For me, this type of reporting ups the quality of our board, even if just a little.