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14 Nov 2005

FO Mailbag

by Aaron Schatz (and the FO staff)

Time for another look at the Football Outsiders mailbag. Actually, a week ago Friday was time for another look at the Football Outsiders mailbag. That become last Friday, which became Saturday, which became today. Um, whoops?

The fact is that we've reached a tipping point in the last couple of weeks where the amount of e-mail and questions in discussion threads is so large that I simply cannot answer it all, or even most of it. Things have been steadily backed up in my e-mail and on my to do list since the start of the season. I lost two and a half weeks of work time in September and I've been trying to catch up ever since, and at the same time the readership has been growing each week, and so has the e-mail volume and the need to keep the discussion threads clear of trolls.

Anyway, if you send in an e-mail or leave a question in a thread and it doesn't get answered, I apologize. I'm trying to get to as much as possible. Remember when I asked for interns to help me out? I'm so backed up with things to do that I haven't had the time to choose interns who would be able to help me with the fact that I'm so backed up with things to do.

Anyway, enough apologies. The best way to get your question answered at this point, if it is a question not related to the DVOA stats, is to send it to one of the other writers via the contact form. And while we will answer questions posed in discussion threads, we are much more likely to answer a question asked through the contact form. When those discussions get filled up with comments, they get hard to follow.

Be aware that we reference plenty of our innovative FO stats here, not to mention their unfamiliar terminology, so if you are a recent addition to the readership you might want to read this first.

Before we get to the questions, the beginning of Loser League Part II this week reminded me that I never ended up sharing with everyone the results of the survey we took with Loser League Part I. Some of you may remember that after you picked your loser league team, we asked you to name your favorite NFL team. We wanted to know where the readers were coming from and who they were rooting for. Now, these numbers have probably changed since we asked the question, because this is from before our deal with FOXSports.com. We'll ask again when we do the Third Annual Football Outsiders Awards after the season and see if things have changed.

Favorite Teams of FO Readers (Start of 2005 Season)
Patriots 13.7% 49ers 3.8% Panthers 3.1%
Eagles 8.9% Seahawks 3.8% Vikings 3.1%
Steelers 6.2% Bills 3.4% Browns 2.7%
Bears 5.2% Jets 3.4% Cowboys 2.7%
Colts 4.5% Lions 3.1% Redskins 2.7%
Giants 4.1% Packers 3.1% Other 22.3%

It's no surprise that the Patriots rank number one among our readers. Our first publicity when we started back in 2003 was from Boston Sports Media Watch, and we've gotten more media coverage in Boston than anywhere else, mostly because I happen to live here. I knew we had a lot of Eagles and Steelers fans reading the site but I didn't realize there were so many Bears fans, and I thought we had more Packers fans reading than this seems to indicate.

Onto the e-mail ...

Mitch Wojcik: Since we're roughly at the mid-point in the season, how do the top teams in 2004 compare to the top teams in 2005, DVOA-wise? In addition, do you see the emergence of any trends in 2005 that differ from 2004?

Aaron Schatz: The top three teams of 2004 (NE, PIT, IND) are all higher than the 2005 Colts. It's also important to remember that the 2004 Eagles were just as high as the top three AFC teams until they stopped playing their starters in Week 16.

As far as emerging trends, do you remember the big rise of offense? Gone. Offense is back to a level halfway between 2002 and 2003. I wrote about this in the New York Times last Sunday. The other thing gone is last year's strange trend where the best defenses were almost all on losing teams. That's not happening so far this year, and it hadn't happened in previous years either. Last year was just a strange case because of the number of teams with great defenses but imploding quarterback situations (Chicago, Washington, Miami, Buffalo).

Ron Anson: Is Red Cashen still refereeing? I like the way he calls "first down".

Michael David Smith: No, Red Cashion is no longer refereeing. He retired in 1997 after a 25-year career that included refereeing Super Bowls XX and XXX. Cashion, a graduate of Texas A&M, was known for the way he enthusiastically drawled "First Down!" Cashion currently serves as chairman emeritus of ANCO, an insurance company.

Todd Schneider: Does the DVOA system reward a team in regard to third down conversions if they never get to third down, i.e., achieve a first down in one or two plays? Denver is bad on third down with more than four yards to go, but their successful drives usually come from the fact that they don't put themselves into third-and-long situations (I give credit to Shanahan/Kubiak for strategizing that way). I would guess that Denver is above the league average in successful drives vs. unsuccessful drives. Therefore, third-and-long is not as big a problem for them as other teams.

Aaron Schatz: Well, when I'm talking about how well a team is doing in a certain situation, you are correct that I do not talk about how OFTEN they are in that situation. And Denver is definitely in third-and-long less than other teams. It doesn't change the fact that it will be a problem when they do get into the situation, but they aren't in it quite as much.

Anyway, there's no reward for converting a third down, per se. The biggest issue here is that the "success points" system has a huge gap on third downs.

  • On first-and-10, five yards is roughly one success point, ten yards is roughly three success points.
  • On second-and-10, six yards is roughly one success point, ten yards is roughly three success points.
  • On third-and-10, there is no way to get one success point. Because of the wacky logarhythms and fractional values stuck in the equation, 7-9 yards will get you something like 0.6 success points, and then ten yards and a conversion suddenly rockets you all the way up to three success points.

That's why third down is so important both in the system and in real life: teams can make up for their failures from the first two downs. But a team like Denver that gets six yards on first down and four on second and never hits third will have a significantly positive value from the first and second downs. So its TOTAL offensive DVOA will be very good, even if its third down numbers are not.

In fact, I'm commonly asked which rates better, a team that gets four yards on every play or a team that goes zero, zero, 12. Both teams will convert every set of downs but actually the more consistent team rates better. That's because there is no such thing as a team that will always convert on third-and-long. You have to take every single down as a separate occurence, and a team that gains 4-5 yards on first downs is putting itself into a much easier situation on second and third down, and doesn't have to depend on having an extreme ability to convert hard third downs. And Denver is this kind of team -- that's partly why the midseason projection system believes they'll be the #1 offense in the second half of the year.

Mark HW: I live in the Twin Cities and shoulder the especially heavy burden of being a Vikings fan. Last Sunday against Carolina, it looked like Fred Smoot was all alone on Steve Smith throughout most of the game. How do the FO metrics take into account poor coaching decisions and schemes? I'm not saying the Vikings are any good, but if you don't make reasonable adjustments, the opposition will take advantage all day long.

Aaron Schatz: We can't. Poor coaching decisions and schemes are just part of the subjective analysis that has to be added to our objective numbers to get a better picture of the game. That's why we write commentaries to go with the numbers. We run straight numbers on our site, but you'll notice that when we write, we always comment on where we think the numbers are missing something.

Sam Mogilensky: Is there any way you could put together some data on whether high-drafted quarterbacks have more successful careers if they sit on the bench for a year or two (or more) rather than starting as rookies? I can already think of one problem with such an analysis, which is that quarterbacks who start as rookies are most likely playing for bad teams, while quarterbacks who sit are probably on good teams. Also, I! don\'t know if DVOA and DPAR go back far enough to get a good sample. But this question has always intrigued me.

Ned Macey: Actually, I dealt with this issue in a year ago and came to some conclusions in this article. The sample size will always be too small to draw adequate statistical conclusions. Further, the success of Palmer, Roethlisberger, and Eli this year shows that different quarterbacks will be able to succeed in different situations. As you see in my article, however, waiting certainly has a higher percentage of successes.

Bill Fish: Your team efficiency rankings appear to be the sum of Offense, Defense and Special Teams DVOA. Is there any type of weighting built into the DVOA ratings? For example, special teams plays account for 15-20 percent of the total plays for a team, yet they have a 33 percent weighting based on the sum of the components. It seems like they are over-weighted.

Also, two-point conversions: special teams plays or offense/defense plays?

Aaron Schatz: To answer the first question, special teams work differently than the rest of DVOA. Unlike offense and defense, which are complicated formulas that try to take into account both total yardage and the ability to gain first downs, special teams just involves straight yards or, in the case of field goals, points. So the special teams ratings are not percentages, they represent points above or below average (field position from punts and kicks is translated into points based on the average number of points a team scores from every yard line on the field). That's explained more here.

But of course I have to turn that into a percentage or else I cannot add it to offense and defense. So I did a regression to figure out what variable X gave you in this equation:

(special teams * X) + unadjusted offense - unadjusted defense = total

with total for every team over multiple years having the closest correlation to winning percentage. This means that special teams DVOA takes into account the fact that special teams are not as important as offense or defense. This is why the special teams ratings are so much closer to zero.

As for two-point conversions, I don't include them at all. Obviously they are very important, but they are too rare to really be predictive. I suppose I could include them in offense/defense just to get a better idea of how well teams defended plays two yards from the goal line. You know, for power rushing or similar stats.

Before we wrap up the mailbag, every so often I run an e-mail when someone needs some information and wants to pose a question to the readership. This week's question is related to pass defense and also might start a fun conversation about football simulation games.

Lee Harris: I design my own cards for the classic "Statis Pro Football" simulation game. The game provides rules on assigning "pass defense" values to each team's secondary. These are distributed to the defensive backs on the team, and affect the completion range of the quarterbacks when they throw to a receiver marked by them.

The problem is, how can I use easily available stats (NFL.com?) to decide which player gets which rating, without having to go through them one by one? Currently, defensive backs are separated into corners and safeties, then ordered by "Pro Bowl?" player, Games Started, and I think that's it. I'm not even sure how ties are broken up.

I've always liked the idea of using Passes Defensed, which is an available stat, but I am aware that the better corners won't be thrown at much, so will tend to have low PD stats. I thought of using PD per game started to avoid that issue, but then a poor corner who just didn't have many PD might end up looking great. So then I thought, could you work in tackles and stuff to estimate how often they're being thrown at, in addition to PD divided by games started or played?

Anyway, that's the kind of thing I would love to discuss with fellow statheads and come up with stuff I can use to modify the game rules. Again, this is purely amateur - the game went out of print in 1992, and so there's just a few enthusiasts who continue to update the rules, make new cards, etc. I have a website devoted to the game here and can be e-mailed at lee.harris4-at-virgin.net.

Posted by: Aaron Schatz on 14 Nov 2005

30 comments, Last at 20 Nov 2005, 6:49pm by Bright Blue Shorts


by Art (not verified) :: Mon, 11/14/2005 - 1:36pm

Hey Aaron, post the new weekly Audibles article you've been doing for the past 2 weeks. It's awesome.


by admin :: Mon, 11/14/2005 - 1:37pm

It is coming, Tim had to edit it this morning instead of last night.

by BlueStarDude (not verified) :: Mon, 11/14/2005 - 1:53pm

Lee, That's a good site you have there. I had never heard of this game before, but it sounds interesting - will be reading more about it.

I have a more generic question along similar lines: what's a good site for obtaining individual player's past season stats?

NFL.com only seems to do the past few years. Pro-football-reference.com is good for skill position players, but doesn't include even basic stats, like G and Games Started, for the defenders, O-linemen, etc.

by Sophandros (not verified) :: Mon, 11/14/2005 - 2:04pm

The pesky Falcons fans from last week should read the Mark HW letter and response...

by pawnking (not verified) :: Mon, 11/14/2005 - 2:13pm

Here's an interesting question: Is there any mathematical reason that Shaun Alexander doesn't get enough love from the media? I mean, I hear more about Larry Johnson than him. Is there a statistical correlation between media mention and geographical location?

by B (not verified) :: Mon, 11/14/2005 - 2:16pm

That’s because there is no such thing as a team that will always convert on third-and-long
Unless that team is facing Pittsburgh.

by the fumble (not verified) :: Mon, 11/14/2005 - 2:31pm

BSD- did you try jt-sw.com? Actually, I don't think that has G and GP for non-skill position players, but it's got more info on special teams than profootballreference.com. I don't know of a website that tracks games played for linemen, try the book Total Football II.

by calig23 (not verified) :: Mon, 11/14/2005 - 2:38pm

The site linked with my name seems to have at least games played for non-skill position players, but I don't think that it has games started.

by FizzMan (not verified) :: Mon, 11/14/2005 - 2:48pm

Aaron Schatz: To answer the first question, special teams work differently than the rest of DVOA... That’s explained more here.

I think there's a link missing here?
Keep up the great work.

by mactbone (not verified) :: Mon, 11/14/2005 - 3:28pm

Re 3:

Actually if you use a search engine like Google and type in a player's name and nfl.com you'll get a web page for the player. I found Morten Andersen and Gary Anderson's stats that way. It doesn't show GS though and I'm willing to bet it only has players that have played in any season starting with 2000.

by Fnor (not verified) :: Mon, 11/14/2005 - 3:41pm

Back in the day, Avalon Hill made some sweet stuff, lots of board games and hybrid board/card games. They kind of petered out in the early 90s and were bought by Wizards of the Coast, a card game producer. I remember this game, though, it always seemed like a really cool idea but kind of clunky to play.

Why not use an adaptation of FO's DVOA vs reciever number? Most teams line up their defenders on recievers in order of skill, so you might be able to convert the percentages to the game's numbers and fudge it a bit for some cases that your gut says are wrong. I forget if they do pass for LBs, but as they keep saying, pass dvoa against RB and TE passes are good for that.

Also, I'm amazed at the number of Brits we see around here. James and then a few other whose names escape me, and now Lee. All of my English friends think football is terribly stupid, except for one guy, and even he's 10000x more of a footy fan. How do you guys get into the sport?

by BlueStarDude (not verified) :: Mon, 11/14/2005 - 3:43pm

Thanks for the points, guys. DatabaseFootball in particular looks promising. The hard thing is trying to find out who, say, the starting linemen were for a team in 1970 or something. For current players, I like ESPN's "player card" format - will usually Google something along the lines of dat nguyen player card, and bingo, instant info.

by admin :: Mon, 11/14/2005 - 3:51pm

Link added.

by MikeT (not verified) :: Mon, 11/14/2005 - 3:54pm

In answer to Lee Harris' Statis Pro question ...

I would not recommend using tackles as a way to evaluate cornerbacks, for just the reasons Lee mentioned: great CBs are avoided, weaker ones are picked on, and great tackle totals are often a sign of a second tier pass defender.

The FO pass defense DVOA, broken down by receiver, would be an excellent tool for creating player cards. I am rusty on my Statis Pro (the ranges went from -2 to +2, I think). But using Strat o Matic language, it's easy to see that Al Harris deserves a "6" rating this year, while Lito Sheppard deserves a "4" at best despite his All Pro status.

A mix of DVOA, passes intercepted and defensed, penalty data, and a dollup of subjective guessing would create ratings to satisfy even the hardcore tabletop gamer.

by Tim Kirk (York, UK) (not verified) :: Mon, 11/14/2005 - 5:07pm

re: 11

Like many people in the UK I first heard about Football in '85 with the Bears. Then went to see friends in Colorado the next year, and had some more of it explained (like the fact that all the pauses were so everyone could scheme and organise planned plays -not just for a quick rest, or a pause for TV adverts...).

So I became a Broncos fan due to having been through Denver... and with so many 49ers & Redskins fans in the UK had some tough Superbowl experiences back then. [Though the biggst Redskin's fan I knew at the time went to bed with beer at 0-10 down in the first quarter, and refused to believe it when people tried to wake him up during the second quarter...]

Since then I've played touch/flag for years (though not recently - would still be up for a social game) and ran a play-by-(e)mail football league for almost a decade as well (currrently trying to work out a way I can restart it for a few friedns and have enough time for the rest of my life...). I guess some of my views on the inadequacies of conventional stats comes from watching (and typing up on-the-fly commentaries) hundreds of simulated games... ( and watching remote coaches evolve their gameplans over a period of time was fascintating - 1st year people went for bombs a lot - 2nd year defenses responded with deep zone and blitz- so toss sweeps and TE/FB pass blocking with HB going out for dump off became prevelant in the 3rd year... and so on...).

Oh, and I remember Statis-Pro from Avalon Hill as well. Might even have the 85,86, 87 cards around somewhere still...

by DMP (not verified) :: Mon, 11/14/2005 - 5:14pm

"The top three teams of 2004 (NE, PIT, IND) are all higher than the 2005 Colts."

But could that be because of the unusually better offenses of 2004 that leveled back a bit in 2005? Is DVOA comparable from year to year? If so, what is the best team of the DVOA Era?

by Jeff F (not verified) :: Mon, 11/14/2005 - 5:48pm

DMP - Keep in mind that if all the teams have better offenses on average, all the teams will have worse DVOAs for defense on average, so it should all balance out fairly well.

To find the teams with the highest DVOA from the "DVOA era", look at the history, there are only 5 or 6 years to look through at the moment. Offhand, it's the 2001 Rams.

by B (not verified) :: Mon, 11/14/2005 - 5:58pm

The highest DVOA is the 1999 Rams, then the 2002 Bucs.

by Ken (not verified) :: Mon, 11/14/2005 - 6:02pm

I'm a Brit too, and have been reading the site since the playoffs in the first year it was up, although I haven't commented that frequently recently. 'American' football was huge in the UK in the mid to late 80s, around the time the American Bowls were still being played at Wembley. I got into it through my dad, who started watching then, and I just picked it up later. There's quite a dedicated fan base in Britain, actually, and when Sky start messing about with when they play it they are good at kicking up a bit of a fuss about it.

As an unrelated but interesting aside, in Britain you can often tell when people started following the game because of who they support. Chicago when they won the SUper Bowl; Miami, Washington, San Fran in the late 80s; then Dallas, Green Bay, Denver... it is a remarkably useful predictor!

by Pat (not verified) :: Mon, 11/14/2005 - 6:03pm

Jeff: Only VOA for a game is zero-sum. Total summed DVOA for the entire league can be positive, negative, or zero - the "over average" part is compared to 2002 (I think?).

by CaffeineMan (not verified) :: Mon, 11/14/2005 - 6:04pm

DVOA is supposed to be comparable from year-to-year. For fun, Top 5 teams from the DVOA era:

1) 42.2% 1999 Rams
2) 40.9% 2002 Buccaneers (Scourge of DVOA! :D)
3) 39.6% 2001 Rams (A dynasty is born!)
4) 36.1% 2000 Titans
5) 35.6% 2004 Patriots

by Vince (not verified) :: Mon, 11/14/2005 - 6:53pm

I spent some time this offseason working on a method of ranking defensive players using only commonly available team and individual statistics. I finally gave up on it, partly because the new season started, partly because I couldn't figure out a system to grade CBs that gave logical results.

The problem is, if you look at each team's total CB stats, the bad teams are all over the leaderboard. CBs on bad teams make lots of tackles. CBs on bad teams get lots of passes defensed. CBs on bad teams don't get many INTs, but on an individual level those are so sporadic that they're useless.

Maybe this offseason I'll try again.

by B (not verified) :: Mon, 11/14/2005 - 7:13pm

Vince, what if you take an individual defender's stats and divide by total defensive plays? So for a CB you'd take passes defended / total plays faced by his defense. That should prevent the leaderboard from filling up with players on bad teams. For rating CBS, I think it's best to pretend tackles don't matter. While it's good to have a CB that can tackle, it's not his primary or secondary responsibility.

by doktarr (not verified) :: Mon, 11/14/2005 - 7:50pm

Though the biggst Redskin’s fan I knew at the time went to bed with beer at 0-10 down in the first quarter, and refused to believe it when people tried to wake him up during the second quarter…


by Kibbles (not verified) :: Mon, 11/14/2005 - 9:05pm

Re #23: Not true at all. The hybrid Cover-2 defense popularized by Tampa relies HEAVILY on CBs being able to make tackles. You don't have tackling CBs, you don't have a defense. I know that Denver and Indy, at the least, are running a hybrid or similar defense to the "Tampa 2". Cornerbacks don't play in Denver unless they show a whole lot of willingness to mix it up in run support. In fact, the average Denver CB loves hitting as much as covering. Champ Bailey's one of the best tackling CBs in the NFL, Kelly Herndon and Lenny Walls were both also very very good, and Darrent Williams/Dominique Foxworth are both very small, but have no problem taking on much larger players. Watch the Denver/NO game last year to see the perfect example of why you shouldn't ignore CBs that can tackle. Champ Bailey finished with double digit tackles (13, iirc), throwing the much larger Deuce McAllister for a loss time and time again. After that game, he was actually on pace for a 100 tackle season, but he fell off a little bit towards the end of the season.

by Vince (not verified) :: Tue, 11/15/2005 - 12:10am

Actually, I used the splits on ESPN.com to differentiate between tackles on running plays and tackles on passing plays. So CBs who were strong in run support weren't punished for it.

It just now occurred to me that I could have tried dividing each team's totals by WR receiving yards allowed or something. Ah well, maybe next year.

by Rodafowa (not verified) :: Tue, 11/15/2005 - 12:13pm

Re: 11

I first got into American football via the old Channel 4 Saturday lunchtime highlights show, which I accidentally tuned into at a young and impressionable age. I adopted the Jets as "my" team (partly and embarassingly because at that point I wanted to be a pilot when I grew up) just in time for the Bruce Coslet Experience, somehow got though that with enthusiasm largely undimmed, discovered John Madden Football on the Mega Drive and the rest is history.

Incidentally, did anyone else in the UK notice the mighty Mike Carlson giving FO kudos for picking the ATL-GB game during Five's coverage of the Monday night?

by James, London (not verified) :: Tue, 11/15/2005 - 2:05pm


Like a number of others, I first got interested in the 80's during the NFL's first wave of interest, but didn't see much,(a combination of being 10 yrs old and minimal TV coverage). I saw some London Monarchs games during the World Bowl era (and the Superbowl where Dallas crushed Buffalo 10,000-3), then sort of lost interest for a while.

I got hooked again at the start of the 2002 season, principally because I got SKY TV, who show live games at a time when you can watch them and still get up for work on Monday! Sadly I didn't see MNF, and missed the Mike Carlson plug. I'm still trying to convince my employer that the SNF/MNF are valid reasons to roll into work at lunchtime.

The easiest way to follow the NFL from the UK is via the web, and I found FO when TMQ mentioned them in his column, and have been coming ever since.

As for my team, I'm a Dolphins fan because the first place in the USA I ever visited was Miami.

by Fnor (not verified) :: Wed, 11/16/2005 - 4:10pm

That is really interesting, all of you, and thanks for sharing. I really had no idea there was such appeal for american football during the 80s, I thought it was mostly just a lot of hype. Nice to know that I was wrong.

by Bright Blue Shorts (not verified) :: Sun, 11/20/2005 - 6:49pm

Another Brit here ... been watching for 21 years. In 1982 a fourth television station, the appropriately named Channel 4, was added to the UK repertoire. It was given a remit of minority interest. About the only sports they showed were American Football, MLB, Sumo and Kabaddi.

It will probably amaze your U.S. readers to know that we had a 75-min programme on a Sunday evening at 6pm; showing the highlights of the best game the week earlier. Imagine that ... 7-day tape delay! That we only had four channels gives you an idea of what the media was like then, and there was nowhere to get Amfoot results so we didn't know any better.

The first live televised Super Bowl was XVII - Skins / Fins - with the match lasting until gone 2am on a Monday. I started watching a couple of seasons later when the Raiders defeated the Fins 45-34. One of the classic matches.

BBS :-)