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Archive for January, 2009

2009 Hall of Fame Finalists

30th January 2009

On January 31, the Hall of Fame selectors will meet and choose the members of the 2009 Hall of Fame Class. The finalists include thirteen "modern" players, two veteran's selections, and two non-player contributors (Paul Tagliabue and Ralph Wilson). I thought I would take a look at how the current Hall of Fame finalist class stacks up to their peers using the Approximate Value rankings that Doug developed last off-season.

Approximate Value is just one tool that can be used to evaluate these players. Keep in mind that these numbers don't in any way reflect post-season results. Further, if a player's career was shortened, then that will impact the total numbers, even if the player was productive while playing. Keeping that in mind, I’ve included four rows of information for each finalist. The first is the raw Approximate Value for the player’s entire career. This is cumulative, so the longer the career, the more years a player had to add to their total. The remaining three rows of information are all position-specific. We are only comparing Bob Kuechenberg to other Offensive Guards, and not to Offensive Tackles.

The first is “Hall of Fame Percentile Rank”. This represents the percentile rank of the subject player compared to the current Hall of Famers at the same position. The higher the percentage, the better. For example, a percentile rank of 70 means that the player’s career Approximate Value (AV) score is higher than 70% of the current members of the Hall of Fame at the same position.

The next row is “Non-HOF with Higher AV”. It is fairly self-explanatory. This is just a raw number of HOF-eligible players at the same position, who have a higher career AV score than the subject, but have not yet been elected. This is not to say that the subject player is worse than all of those, because remember, this is “approximate” value. It’s just another way of illustrating how clear cut the player is to others at the same position.

The third row is “% of Similars in HOF”. Here, I found all HOF-eligible players who are within 10 AV points, plus or minus, of the subject’s career AV. The % represents the number of players within +/- 10 points who are already in the Hall of Fame. Just like the Percentile Rank, the higher the number here, the better.

I didn’t include players who are not yet eligible either because they are still active or retired fewer than five years ago. While this is probably a wash at most positions, at a position like receiver, it means that Cris Carter and Reed appear better than they would if they were also compared to Jerry Rice and the current crop of still active players, of which several are likely to make the Hall, and already rank higher than Carter and Reed in career AV. Here are the fifteen finalists for the Hall of Fame, listed in descending order of Approximate Value.

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Posted in Approximate Value, General, History | 24 Comments »

Are all 10 point leads the same?

29th January 2009

Over at the Advanced NFL Community, the claim was made that not all 10 point leads are the same. Here's the meat of the argument:

Let's say your team is up by 10 with 8 minutes remaining. That's a pretty good lead, right? Well, if it's a 13-3 game, it's a VERY good lead -- if their poor opponents couldn't muster more than a field goal in 52 minutes, they're unlikely to close a 10 point gap now. On the other hand, if it's a 42-32 shoot-out, it's still anybody's ballgame[.]

That sounds reasonable, but whenever I hear arguments like this I always raise an eyebrow and wonder if common perception matches reality. After all, ten points is ten points, and maybe it's equally likely that a team trailing 13-3 will win its game compared to a team trailing in a shootout. A touchdown and a field goal can be scored by almost any team in a short time, and the small sample size of less than one game may not be that telling of the team's offensive prowess.

So how do we measure this?

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Posted in General | 10 Comments »

Super Bowl Squares

26th January 2009

See also: PFR Super Bowl Squares mobile app

This is a re-run of a post I ran a year ago:

Three Super Bowls ago, I wrote this post over at Sabernomics. In it, I looked at your probability of winning a squares pool with any given square. For example, I found that in a one-unit-per-square pool, either of the '0/7' squares would have an expected value of about 3.8 units. Compare that with, say, a '5/6' square, which has an expected value of 0.22, or the lowly `2/2' square and its expected value of .04. Because it was all the data I had at the time, I only considered the last digits of the final scores of games, but someone correctly pointed out in the comments that most pools also give prizes for (the last digits of) the cumulative scores at the end of each quarter.

Well, now I have score-by-quarter data for the entirety of the NFL's 2-point-conversion era (1994--present), so it's time for an update.

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Posted in General | 14 Comments »

Super Bowl History at P-F-R

23rd January 2009

Brand New Super Bowl History Section at P-F-R

Fortunately for all of us, Justin Kubatko of fame is also a football fan. Like 47% of all football fans, he's a Steeler fan. So he's fired up about next weekend's big game, fired up enough that he took a short break from cataloging the exploits of Kobe and LeBron and, with a bit of help from me, put together a bunch of cool pages and tools that now constitute the most detailed and interconnected statistical Super Bowl History on the web.

Here's a quick tour...

Box Scores and gamelogs for Super Bowl I through XLII.

All-Time Leaders and Cumulative Team Standings

All Passes, Runs and Catches by every player in Super Bowl history, fully sortable.
For example: Bart Starr, Jerry Rice, Franco Harris, even The Fridge! These play-by-play logs are also linked from the player pages, just above their main stat table.

The Super Bowl Play Finder allows you to search for Super Bowl plays by a wide range of criteria. Here's just a sampling of the trivia you can find with this tool:

You can even use it to fashion yourself a play-by-play account of a given Super Bowl (here's XXXII, for instance). Unfortunately, these aren't as complete as they will someday be. For now, only rushes and pass plays are included. So no sacks, and no kicks. We will get those added at some point.

As always, there are likely a few bugs lurking within those pages. Let us know if you find them.

If you like these additions and want to support our ongoing work, please consider sponsoring your favorite player or team or both. User support makes improvements like this possible.

Posted in History, P-F-R News | 26 Comments »

The Best Super Bowl Loser Ever, Part 2

21st January 2009

Yesterday we took a look at some of the statistics of the 43 teams to ever lose a Super Bowl, and I began the complicated task of ranking the top Super Bowl losers. Four great offenses -- the '90 Bills, '84 Dolphins, '83 Redskins and '69 Raiders -- made the cut but fell outside the top five. Today we'll take an in depth look at one man's view on the five greatest Super Bowl losers of all time.

5. 1978 Cowboys. Don't let the 12-4 record deceive you. The Cowboys ranked 1st in points scored and 3rd in points allowed. Dallas had five Hall of Famers on their team, including Tom Landry. Unfortunately for them, they ran into a team with nine HOFers and Lynn Swann, and lost one of the closest Super Bowls of all time. And if not for Jackie Smith, they might not even be on this list.

What makes this team special?

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Posted in History | 20 Comments »

Best Super Bowl Loser Ever

20th January 2009

A year ago, I wrote that the 2007 Giants were arguably the worst Super Bowl Champion of all time, with the '70 Colts, '80 Raiders, '87 Redskins and '01 Patriots hot on their heels. That subgroup is, IMO, the bottom tier of Super Bowl winners.

Some comments requested a showing of the opposite -- the best Super Bowl losers ever. We all know the answer to this one: the 2007 Patriots, right? Well, maybe not. Let's take a look. For starters, let's take a look at the regular season record of each of the 42 Super Bowls losers.

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Posted in History | 18 Comments »

Super Bowl Winners, SRS champs, ANY/A and AYPC

16th January 2009

I don't think this post will shed any light for our regular PFR readers, but I propose that from now on, we rank passing offenses not by passing yards but by either adjusted net yards per attempt or by Value - the number of adjusted yards gained over the league average.

Adjusted net yards per attempt, of course, is calculated by adding 20 yards (previously 10 yards) for each passing touchdown, subtracting 45 yards for each interception, subtracting sack yards from gross passing yards, and dividing this adjusted yardage by the combined number of sacks and attempts. That gives you the adjusted net yards per attempt for every player or team. To get their Value, you would subtract the league average from that number and multiply the difference by their number of combined sacks and pass attempts.

To me, this is a much better way to rank team passing. For example,

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Posted in History, Statgeekery | 19 Comments »

More on familiarity and home field advantage

15th January 2009

Yesterday JKL posted some intriguing numbers concerning visiting teams' fortunes the second time they play in a particular stadium in a year. The implication was that, possibly, a nontrivial portion of that rich stew we call Home Field Advantage might be due to familiarity with the peculiarities of the venue.

I decided to follow up on this with another quick study.

In the playoffs, Joe Flacco tells me, there are no more rookies. And in the second halves of games, there are no more unfamiliar stadiums. Or something like that. What I'm getting at is: if familiarity plays a meaningful role in home field advantage, we might expect it to be most prominent early in the game.

Now, home field advantage seems to be greatest in the first quarter for all games in general. But if familiarity is a meaningful factor, the first quarter advantage should be even more pronounced in games where the road team doesn't visit the stadium often.

I looked at all regular season games since 1978 that were either:

intra-division games, in which the road team should be fairly familiar with the surroundings because it plays there every year.


inter-conference games, in which the road team should be mostly unfamiliar with the surroundings. This has varied over the years, but in the current scheduling format a team will visit an inter-conference opponents' stadium only once every eight years on average.

I want to emphasize that this is a pretty sloppy study. I didn't do anything to account for new stadiums. I didn't account for the fact that the Jets and Giants share a stadium. I didn't account for divisional realignments, which could create some unfamiliar intra-division matchups. And so on.

Disclaimers out of the way, here is the summary table. This shows the average point margin between the home team and the visiting team for the given time period.

                   Qtr 1    rest of game
Intra-divsion       0.78       1.86
Inter-conference    1.20       1.76
Difference         +0.42      -0.10

Inter-conference hosts got about 40% of their home field advantage in the first quarter, whereas intra-division hosts only got about 30% of it in the first quarter. Interesting.

Here's another fact: in the intra-division games, the home team scored first 55% of the time. In the inter-conference games, the home team scored first 58% of the time. That may not seem like a big difference. And in fact it isn't a big difference. But it's probably a real difference, and not just noise (p =~ .02, if you're into that kind of thing).

Posted in Home Field Advantage | 11 Comments »

The Boys are Back in Town

14th January 2009

In one of the greatest Super Bowl upsets of all time, the upstart AFL Champion New York Jets beat the NFL Champion Baltimore Colts, 16-7, in Super Bowl III, to give the AFL its first Super Bowl victory and instant credibility. Let me give you an explanation you've never heard to make sense of such a game. The location was the Orange Bowl, where the Jets had played just four weeks earlier in the regular season finale against Miami. The Jets team played there in '67 and '66, too. Baltimore? They had never played a game at the Orange Bowl--never even played a regular season game in Florida.

Fast forward to last weekend, when the Arizona Cardinals traveled to Carolina, where they had lost by 4 points in the regular season. The Cardinals had struggled over the final month of the regular season, were 0-5 in road games played on the East Coast in 2008, and would be without WR Anquan Boldin. They weren't given much of a chance on the road, and entered the game as a sizeable double digit underdog. Two years ago, in my very first post as a member of the "staff", I predicted that the Arizona Cardinals would enjoy an increased home field advantage in 2007, with the rationale being that teams in new stadiums enjoy a familiarity advantage over road teams who have never visited the stadium before, particularly after the home team has had some time to develop its own comfort with playing in the new stadium. Over the last two seasons, the Cardinals have gone 12-4 at home (and one of those losses in 2008 was to a team who had previously played in AZ) and only 5-11 on the road, for the largest home/road differential in the league over the last two years.

In the first round of the playoffs, thanks to the rule that gives division winners with worse records the higher seed, the underdog Cardinals drew another first time visitor to University of Phoenix stadium, the Atlanta Falcons, and jumped on them early en route to a 30-24 victory. But the divisional round game against Carolina was on the road. Yet, despite that, familiarity may have still given the Cardinals an assist in reversing the regular season fortunes. Now, they return home to face another team that has never played a game at the new stadium, the Philadelphia Eagles. The winner will become the second team to advance to the Super Bowl with 9 wins, since the league went to a 16-game schedule. Oh, and by the way, the last team to do so, the 1979 Los Angeles Rams, advanced by avenging regular season road losses at Dallas and Tampa Bay. The Rams then played the heavily favored Steelers in the Super Bowl, not in their home stadium, but a few miles away at the Rose Bowl, and had the lead entering the final quarter before the Steelers pulled away late.

Now I won't be so naive as to tell you that familiarity with a stadium is outcome determinative. But I think it's a small, and more importantly, underappreciated part of determining who wins games (or who stays competitive in them). Why is it a factor? Well, it could be related to many different things, all which may come into play. Field surface and conditions could be just one of the factors. Wind patterns (created by unique features of a stadium) could be another. Sound conditions created by each stadium design could be another. Weather patterns and climate is certainly another strong one, where teams from similar playing climates are comfortable and used to playing under the conditions, while those from disparate climates are not. Sun conditions and lighting patterns in the stadium. Heck, the color of the locker room, types of showers. Anything that might be different could come into play, almost imperceptibly, to cause sub-optimal performance.

I've cited three examples where it may have helped some underdogs make history, but let's look at all the info, not just isolated cases. Since 1970, and including last weekend's games, there have been 129 occasions where two teams have played at the same location in both the regular season and post season. I think it's important to further sub-group those games. 56 of those were divisional rematches, and 73 were games between conference opponents. Last January, I also wrote about the playoff bye week and whether it increased home field advantage in the divisional round (concluding it does not). That post also contains data on climate effect in the post season. I think its also important to account for the powerful influence of climate differences on home field advantage in the post season, so I divided those 129 games by whether they were divisional or conference rematches, and by whether the road team had a cold weather climate disadvantage or not.

Type			Season	PF	PA		Playoff PF	PA
DIV-Weather		3-12	20.5	25.3		2-13	14.3	25.6
DIV-No Weather		17-24	19.4	22.2		19-22	18.8	21.4
CONF-Weather		4-15-1	18.2	26.6		6-14	16.9	24.1
CONF-No Weather		9-44	17.0	27.2		15-38	18.6	25.0

And to make it a little clearer, here is a continuation chart showing the average point differentials in both the regular season and playoff games, for each category.

Type			Season PF-PA	Playoff PF-PA	Point Diff. Change
DIV-Weather		-4.8		-11.3		-6.5
DIV-No Weather		-2.8		-2.6		+0.2
CONF-Weather		-8.4		-7.2		+1.2
CONF-No Weather		-10.2		-6.4		+3.8

So let's talk about what is here. When a division opponent with a climate disadvantage gets a second shot, it doesn't really matter. In fact, the climate effect is strong and the drop off is severe. When division rivals meet again, and the teams are either from similar climates or the colder weather team is on the road, there is no change. This makes sense. For these teams, one extra game isn't going to make much difference. They have already played in the stadium continually for several years.

However, we do see improvement in the second game when the opponents are not from the same division. Here, the teams are not accustomed to playing on the same field every season, so the additional chance to return to the same stadium a few months later improves the performance. For the games where the road team is not at a climate disadvantage, the improvement is by close to four points on average. Only three of these conference road rematch teams had a twenty point or more dropoff from the previous result (Denver at Indianapolis, 2004; Minnesota at San Fransisco, 1988; Pittsburgh at Oakland, 1973). In contrast, twelve of the road teams had a twenty point or more improvement over the regular season result.

road	home	year		Reg Season		Playoffs
PIT	IND	2005		L 7-26		W 21-18
LA RAM	TAM	1979		L 6-21		W 9-0
NYG	LA RAM	1984		L 12-33		W 16-13
ARI	CAR	2008		L 23-27		W 33-13
LA RAM	DAL	1979		L 6-30		W 21-19
PIT	DEN	1989		L 7-34		L 23-24
SEA	CHI	2006		L 6-37		L 24-27
NWE  	PIT	2004		L 20-34		W 41-27
DAL	SFO	1981		L 14-45		L 27-28
KAN	HOU	1993		L 0-30		W 28-20
MIN	LA RAM	1977		L 3-35		W 14-7
DAL	LA RAM	1978		L 14-27		W 28-0

I don't think the +3.8 point improvement for these conference road teams is entirely due to the familiarity effect of getting to return to the same stadium. I think there are two other factors at play as well. First, most of these teams lost and performed worse than expected in the first matchup, so there is some natural regression. Dallas, for example, lost by 31 to the San Fransisco 49ers during the regular season, but that result was the anomaly. Second, there is probably also some overconfidence/let down by the home team. After all, they've already beat the team once before at home (often impressively), so they should be able to do it again. Of the nine teams that won the regular season matchup on the road, only three won the playoff rematch (including Baltimore at Miami this year). Thus, twelve of the forty-four losers were able to reverse the results, and ten others lost by a touchdown or less. That said, I do think the familiarity concept is playing a role.

How might all this apply to this weekend's championship games? Well, in the AFC Championship Game, Baltimore and Pittsburgh are similar climate division rivals. As I first discovered in this post, these similar climate rivals (all AFC North games, New England/NY Jets/Buffalo, Chicago/Green Bay, Philadelphia/NY Giants/Washington, San Diego/Oakland, and recently, San Fran/Seattle) show virtually no home field advantage. We've already seen this last week, as the Eagles won at the Giants for the second time in one season. Thus, it should matter very little that this game is being played in Pittsburgh. Pittsburgh is trying to beat Baltimore for a third time, but both games were extremely close and Baltimore had a lead in both late.

In the NFC Championship game, on the other hand, the Eagles will be playing at University of Phoenix Stadium for the first time. Most objective measures would rate the Eagles as the stronger team, and they have already defeated the Cardinals handily. However, the home field advantage that the Cardinals are currently enjoying is an equalizer. I think the Eagles should still win because they are the better team, but IF the Cardinals advance to their first ever Super Bowl, the concept of stadium familiarity will have provided a silent assist.

Posted in Home Field Advantage | 7 Comments »

Sample size vs. sample relevance

12th January 2009

On Sunday morning, we posted some thoughts about the Titans' decision to kick a field goal instead of going on 4th-and-inches. Among the many considerations, perhaps the most important was this: what was the Ravens' chance of scoring on the ensuing drive? There was discussion of that in the post, and more in the comments, and the main disagreement centered on whether Ravens' previous ten drives from that very game were a better barometer of their chances of scoring than, say, the few hundred drives in which the Ravens offense and Titans defense took part during the 2008 season.

And this is an issue with broader applicability. You run into it all the time when you're trying to assess probabilities having to do with football (and probably other things too, but I wouldn't know anything about that).

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Posted in General | 13 Comments »

Should the Titans have gone for it on 4th-and-inches, down by a field goal with four minutes left?

11th January 2009

A discussion broke out between Chase, JKL, and I on this. When it started, Chase and JKL agreed on the answer, and I had a dissenting opinion. When it was over, we all agreed.

Who changed who's mind, and how?

Read to find out, and add your own thoughts:

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Posted in General | 15 Comments »

Overtime Rule Change Proposal: Last Clear Chance

9th January 2009

Following the Colts loss to San Diego, where Manning did not touch the ball in overtime, Peter King wrote that the overtime rule was the "dumbest, stupidest, and most indefensible rule" the NFL has. Now, I don't think it's actually the dumbest rule.

For example, last year I proposed that the league should eliminate the automatic home game for division winner rule and allow wildcard teams with better records to compete for home games. The owners tabled a similar proposal put forth by Roger Goodell and the competition committee last off-season, but I predict that something similar will be in place by the 2011 season if not earlier. The primary reasons I saw from the owners for rejecting it really don't hold water. "It will diminish the value of a division title"--I think that teams that play one of the easiest divisions of all-time and go 3-7 outside of the division do that. "It will hurt teams that play in tough divisions and reward wildcard teams that play in easy ones"--absolutely false based on history, as the strong wildcard teams generally play in tougher divisions and lose out because of being paired with a #1 or #2 seed. If a team wins a division at 9-7 or worse (and thus every other team had 9 or fewer wins), then I submit that the division was in fact, not a tough one. "Tradition: Division winners have always been granted a home game"--again, this is not true, unless tradition goes back to 1990. The NFL has, and I believe will again, changed its playoff structure for the better. Until 1975, for example, division winners with the best record could be forced to go on the road based on a pre-set rotation that assigned home games, without considering a team's record. But I digress.

Like Doug did a couple of years ago,I realized that I've not publicly championed a different overtime system. Like Doug, I also don't have a particular dislike for the overtime system the NFL employs. In fact, it has some nice features-it is simple and fair, oh, and both teams know what the rules are. Prior to the coin flip, both teams have the same chance of getting the ball. Now, Peter King doesn't like it because their is alot of luck tied up in that pre-coin flip fairness. So I've got a solution that solves King's issue (the coin flip) and also, much like Doug's earlier suggestions, should reduce the actual number of overtime games by increasing the incentive to avoid it.

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Posted in General, Rant, Rule Change Proposals | 44 Comments »

Bill James supports BCS boycott

8th January 2009

Thanks to Dr. Saturday for the pointer to this Slate article, in which Bill James articulates his reasons for not liking the BCS.

I don't have time to comment on all the items in the article that deserve comment, so I'll just say that, like everything Bill James has ever written, it's worth a read. I do have a question, though, for those out there who are a bit more in touch with what James has been doing for the past decade or so:

When did James start to refer to himself as a statistical analyst?

Twice in this article, he makes it clear that he does in fact consider himself to be one. My (possibly erroneous) recollection is that James has always specifically denied that, opting instead for something along the lines of, "I'm not a stat guy. I'm simply a guy who likes to ask questions, and then exhausts all possible avenues (some of which might happen to be statistical) of answering that question." Can any of you serious sabermetricians --- I know you're out there --- shed some light?

Posted in BCS, College, Non-football | 9 Comments »

Do specific matchups matter?

7th January 2009

Two teams are, all things considered, exactly equal. They're playing tomorrow on a neutral field. This game is a 50/50 proposition.

Now suppose I give you two more pieces of information: one of the teams has a very poor pass blocking line, and the other has a very good pass rush.

Is this game still a 50/50 proposition?

The 2001 Falcons and Saints provide a decent concrete example, with the Falcons playing the role of the sieve and the fearsome twosome of Charlie Clemons and Joe Johnson fueling New Orleans' league leading pass rush. Both teams, though, were 7-9 and they had a point differential within 10 points of each other.

Conventional wisdom would, I think, say that this game is not a toss-up. The team with the matchup to exploit --- the Saints in this case --- would have the edge.

I've always been a little suspicious of that line of thinking. If the teams are of equal quality overall, then the team with the bad pass blocking line must have advantages over the good pass rushing team in other areas. The 2001 Saints turned the ball over a lot, for example. Those advantages might be less extreme, but they have to add up to the same thing if the teams' overall strengths are equal.

Or do they? The logic I just outlined assumes that matchup advantages are additive and not multiplicative. But that might not be true. Maybe one big advantage is better than three or four little ones. Or maybe it's not.

This is obviously a complicated question, but I decided to take a very quick stab at it.

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Posted in General | 7 Comments »

Late Season Fades and Old Quarterbacks (plus, Romo may not be entirely to blame)

5th January 2009

Several teams who were in prime position for a playoff spot one month ago struggled greatly in December and now find themselves at home. Four teams--Dallas, Denver, New York Jets and Tampa Bay, lead the way with their late season performances. For Dallas and Denver, this is nothing new. As Doug noted in this post from two summers ago, since 1978, Denver has the largest drop among teams between their winning percentage in the first 12 games of the season, and the last 4 games. Dallas was not too far behind.

I've got some thoughts on this that I want to explore further when I have time in the offseason, but it basically has to do with the fact that these teams play more "long" road trips than anyone else. Denver plays virtually every game in a different time zone, and the closest road trip is over 500 miles away, to Kansas City. Dallas, for those that may not realize it, is not in fact located in the Eastern part of the United States. They play three divisional games at a great distance from home, and unless Houston or New Orleans happen to be on the road schedule, also don't play any teams within 500 miles from home. This year, Dallas' closest road game was in Saint Louis. Perhaps these constant long trips (while teams from the East get to play at least half their games within a stone's throw of home) have a cumulative effect that results in reduced performance late in the regular season.

The other issue that I wanted to examine was teams with older starting quarterbacks. We've seen the Bucs with Jeff Garcia finish 0-4 after a 9-3 start (though it had as much to do with defensive collapses as Garcia), and also got to witness the complete collapse of Brett Favre with the Jets. This got me thinking, is there evidence that teams with older quarterbacks hit a wall. So I pulled every non-strike season since 1978 in which a quarterback who was age 35 or older threw at least 350 passes for a team, and recorded the team's record over the first 12 games, and the final 4 games, to see how these teams did down the stretch. Basically, I wanted to see if the Jets/Favre example was random, or if other older quarterbacks had led teams that faltered down the stretch. Without further ado, here are the results, sorted by age of the quarterback:

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Posted in General | 13 Comments »