NFL post-season correlations between wins and various stats

++Addition++Steve Sailer comments:

Regarding turnovers, another way to look at them is to separate interceptions and fumbles, and then look at total fumbles versus fumbles lost. It seems pretty likely that once the ball goes on the ground, it's sheer luck who winds up with it. (Both teams grapple like mad to get the ball.) So, the number of fumbles in a game is a measure of skill, but the percentage of fumbles lost is the most obvious and perhaps most important single measure of luck.

My emphasis on what strikes me as one hell of an insight into the game.

---

Having looked at several years of regular season NFL data, my working assumption is that, more than anything else, winning is about having an offense that is capable of moving the ball through the air, and that such an observation has not just contemporary relevance, but is historically descriptive as well (though the trend has become increasingly pronounced over time). It's boorish to so audaciously insinuating that I've discovered the key to success (not to mention a little painful, as I grew up as a votary of "Marty Ball"). If utilizing an occasional run for no other reason than to keep intact the integrity of the play action is how to become this year's Kansas City Chiefs, well--wait, at 9-0, they're 27th in passing and 12th in rushing. Like I said, boorish.

Speaking of our hometown Chiefs, juxtaposing the ball-controlling, defensively-led, conservative-play-calling Chiefs' style with the high-flying, shoot-out-welcoming Broncos is timely enough. I'd be happy to have this post thrown in my face this Sunday night, but if I had to bet on it, I'm not betting against Peyton Manning, aging agitated ankles be damned.

Sports commentators--many of them former players--regularly espouse phrases like "defenses win championships" and "to win, they'll need to maintain the ground game" in the post-season. Even if being able to pick apart the bottom of the division during the regular season gets a team into the playoffs, perhaps the dynamics are different at that elite-of-the-elite level.

Looking at the results from the last five years of post-season play (60 teams), the following stats correlate with playoff win percentage as relayed in the table below. Italics indicate a correlation in the 'unexpected' direction (average yards gained per rush play correlating inversely with winning, for example--that is, the more efficient a team has been moving the ball on the ground, the worse they tend to fare). Asterisks indicate a lack of statistical significance in the correlation at 95% confidence:

Offense	Wins
Turnover ratio	.62
Passer rating	.52
Yards per pass play	.45
Time of possession	.31
Yards per play	.27
3rd down conversion %	.26
Total yards gained per game	.25
Rush yards per game	.24*
Pass yards per game	.15*
1st downs per game	.10*
Yards per rush play	.10*
Defense
Rush yards allowed per game	.42
3rd down conversion % allowed	.34
Opposing passer rating	.31
Yards allowed per pass play	.28
Yards allowed per play	.20*
Yards allowed per game	.18*
Yards allowed per rush play	.08*
Pass yards allowed per game	.07*
1st downs allowed per game	.02*

A few notes:

- Turnover ratio and time of possession are no more justifiably classified as offensive than as defensive.

- This methodological approach probably doesn't work as well in the post-season as it does during the regular season due to issues like home field advantage, #1 and #2 seeds having a buy week, more weather variation than during the regular season, etc, but it's still useful.

- Special teams stats are not included. They are far less informative than defensive and especially offensive numbers during the regular season. I expect nothing different in the post-season based on the similarities between offensive and defensive correlations during the regular seasons and post-seasons. Due to the time required to do this sort of data, I elected not to include special teams stats.

Relative to what we find during the regular season, turnovers are even more crucial in post-season play than they are during weeks 1-17. That's comprehensible given that teams are generally more evenly-matched during the playoffs than they are during the regular season, so giveaways are harder to overcome than they are during the regular season.

The quarterback spot is football's marquee position, and justifiably so. Just as is the case during the regular season, there is little that is as predictive of winning as a QB's passer rating in the playoffs. Using the bemusing formula has an advantage over other stats that are based primarily on simple averages--it negates the problems this sort of analysis has when teams intentionally run out the clock by keeping the ball on the ground, a phenomenon which tends to make winning teams' rush stats look relatively poor and losing teams' rushing defense looking correspondingly good, since both sides know what's coming.

The advantage yards-per-pass-play has over yards-per-rush-play isn't quite as pronounced as it is during the regular season, but it's still enormous.

Defensive stats simply aren't as explanatory as offensive stats are. Rush yards per game is often an artifice of the occurrence mentioned above--teams that give up a lot of yards on the ground tend to lose because winning teams tend to run a lot towards the end of the game against teams they're beating, even though said losing teams aren't necessarily any less efficient at stopping the run than winning teams are, as the weak relationship between winning and yards given up per rush play illustrates.

Opposing passer rating and yards per pass play, along with 3rd down conversion % allowed, are the only other major statistical indices considered that reach statistical significance, an expected converse of the success having an offense that is able to move the ball through the air brings.

Super Bowl and conference championship point differentials over time

Following this year's superb* Super Bowl, Steve Sailer wondered if the big game keeps getting better. He writes:

My impression is that Super Bowls are seldom the stinkers they used to be so regularly.

To try and quantify this, I looked at point differentials for every Super Bowl and averaged them by decade in an attempt to get some sense of how accurate that impression is:

Decade	PtDif
'60s	17.3
'70s	11.6
'80s	21.9
'90s	14.2
'00s	9.8

I was introduced to football as a second-grader living in Coppell, a Dallas suburb, the year the Cowboys put an exclamation mark on the NFC East's domination of the Bills. The eighties, though, is the decade when some of the most lopsided games in the league's history occurred. Just take a look at Super Bowls 18-24. Only the Montana-Esiason matchup was 'worth' watching.

Yet as Steve points out, there are ineptly played games where the final score nonetheless ends up being close, as the seventh Super Bowl illustrated. Defensive ineptness isn't something spectators tend to get too upset over, as long as it isn't limited exclusively to one side. For a general audience, the higher scoring, the better. The average combined total score in Super Bowls by decade:

Decade	AvgPts
'60s	36.3
'70s	37.0
'80s	49.7
'90s	53.4
'00s	46.1

Super Bowl 46 comes in on the low-end of scoring by the standards of the last few decades, adding to the perception that it was a boring game. This seemingly permanent shift towards higher scoring that has been firmly in place for the last few decades is probably the biggest reason games today feel better than they did when Steve was a kid. Something around 34-31 is probably ideal in terms of maximizing viewer satisfaction.

Steve also recalls observing when he was younger that:

Conference championship games were often thrilling, but Super Bowls were typically a waste of time.

Using the same simple point differential method employed previously, the following table additionally includes the average point differential for conference championship games by decade from the time of the NFL-AFL merger to the present:

Decade	SB Dif	Conf Dif
'70s	11.6	14.5
'80s	21.9	14.0
'90s	14.2	13.2
'00s	9.8	11.7

My historical impression is that conference championship games have been a lot better since I started following the league than they were when before then, but maybe that's skewed by the fact that shutouts didn't used to be the rarity that they are today. As late as the mid-eighties, the NFC championship game featured three consecutive shutouts in a row, as the Bears (who proceeded the following year to shutout LA), Rams, and Redskins were each held to zero. It's only happened once since in either conference since then, when the Giants drubbed the Vikings during the '00-'01 post-season.

* A commonly held perception of the game is that while it was unarguably competitive, it was boring. The Super Bowl draws twice the number of viewers that each conference championship does, and they're of course more watched than any of the other contests throughout the season are. So it's probably not much of a stretch to say that the majority of Super Bowl viewers aren't really fans of the league. For many of them, it's the only NFL game they'll watch all year.

I understand that perspective (though it's not one I share). From it, huge gains, momentous errors, and lots of lead changes are exciting highlights (along with the commercials, which have become a great selling point in getting people who have no interest in the sport to watch the game at parties) in an otherwise bland four hours of faceless men running into each other. The only especially memorable play was Mario Manningham's terrific catch (off a beautifully placed Manning pass) along the sideline just minutes after he'd given up a reception by losing track of the sideline. There was only one turnover, and it might as well have been a punt. Both offenses were efficient and both defenses played well, with the difference being a series of dropped balls by Patriots' receivers and Brady's bizarre intentional grounding that resulted in a safety on the first play from scrimmage for New England's offense.

2011 NFL regular season wins and stat correlations

With the conference championships teed up for next weekend, here are correlations between several stats and wins during the 2011 NFL regular season. This isn't a sports blog, and I'm not making any audacious claims about being able to provide special insights. Just the raw correlations for entire teams here, next to the same for last year for comparative purposes:

Offense	2011	2010	2009
Team passer rating	.79	.68	.81
Team points scored	.77	.71	.88
Yards gained per pass play	.72	.49	.80
Total yards gained	.63	.49	.77
1st downs	.61	.51	.70
Total yards gained per play	.60	.43	.81
Pass yards gained	.59	.30*	.68
Turnover ratio	.56	.72	.69
Time of possession	.55	.61	.46
3rd down conversion %	.53	.64	.64
QB hits allowed	(.40)	(.31)*	(.53)
Sacks allowed	(.29)*	(.26)*	(.53)
4th down conversion %	.26*	(.05)*	.25*
Rush attempts	.19*	.48	.12*
Pass attempts	.17*	(.06)*	.14*
Yards gained per rush play	(.10)*	(.05)*	(.09)*
Rush yards per game	(.07)*	.35	.04*
Total team penalty yards	.04*	(.08)*	.11*
Offensive penalty yards	(.03)*	(.11)*	.04*
Pass:Run ratio	(.01)*	(.31)	.02*
Special teams
Average net punt	.38	(.08)	.27*
Average yards gained per kick return	.38	.23*	.05*
Average kickoff distance	.26*	.08*	.32
Average kickoff return yards allowed	(.11)*	(.13)*	.15*
Field goal %	.07*	.08*	.03*
Defense
Rushing yards allowed per game	(.60)	(.56)	(.58)
Points allowed per game	(.58)	(.72)	(.68)
Opponent's passer rating	(.56)	(.54)	(.47)
Yards allowed per pass play	(.35)	(.49)	(.57)
4th down conversion % given up	(.33)	.03*	(.30)
Passing yards allowed per game	.28*	(.13)*	(.24)*
3rd down conversion % given up	(.18)*	(.13)*	(.23)*
Sacks made	.15*	.30	.41
Defensive penalty yards	.13*	(.01)*	.14*
1st downs given up per game	(.10)*	(.43)	(.45)
Total yards allowed	(.09)*	(.47)	(.56)
Yards allowed per play	(.09)*	(.32)	(.54)
Yards allowed per rush	(.05)*	(.16*)	(.33)

* not statistically significant at 90% confidence

Quarterbacks are king. Teams that move the ball through the air, win. Teams that can't, don't. The difference between having a play maker with a rifle for an arm like Jay Cutler and a dud like Caleb Hanie is starting off 7-3 and finishing 1-5. Need we even mention Peyton Manning?

The 2011 season felt to this fan more like 2009, which Steve Sailer deemed the year only passing mattered, than it did 2010. Indeed, the correlation with wins and the statistics presented above between the 2011 and 2009 seasons is .84, even more rigorous than the .76 correlation between 2011 and 2010.

OneSTDV, on why the NFL is the most popular sports league in the US:

The NFL is now the ultimate sports behemoth, perhaps as a result of helmets and pads covering up black superstars and whites still dominating the marquee positions of QB and head coach.

I'm unclear as to how strong the relationship between professional sports players' demographics and the popularity among the public of the sports they play is. The NHL and MLS are both a lot whiter than the NFL while remaining far less popular than that football behemoth is. Over the last few decades, the MLB has become increasingly non-black and yet has experienced a long-term decline in popularity not just among blacks but also among whites to such an extent that football, not baseball, now clearly deserves to be referred to as America's favorite pastime. But it's hard to argue that in football's most important position, whites are in fact overrepresented relative to racial composition of the country as a whole.

While assertions that "defenses win championships" inevitably abound during postseason play, the offensive correlations are considerably and consistently stronger*. That total rushing yards allowed--not yards per attempt, but total run yards given up--correlates more strongly with wins than any other defensive stat does says a lot about offensive predominance. When defenses give up a lot of rushing yards in a game, it's often because the opposing team spent a good chunk of the second half on the ground to burn off the clock and avoid costly turnovers while protecting an early lead that the losing team's offense couldn't match.

To argue that offense matters more than defense does might seem like arguing that it only matters how hard your side pulls on the rope in tug-of-war, not how hard the other side does. Yet defenses in the NFL are mostly fungible. Tampa 2 is a bit of an exception, where the outsized importance of the middle linebacker is akin to the quarterback's, albeit to a lesser degree, but the phrase "cookie cutter" gets (over)used so often because it is accurately descriptive. If an offense can move the ball in the air against a standard NFL defense, that team is likely to be found still playing in January.

It's sometimes asserted that special teams are one-third of the game. It's not true in terms of duration and rarely feels like they are as important as downs from scrimmage. The table above confirms that feeling.

Turnovers and penalties? Turnovers, yes. Penalties, not so much. The Colts and Cowboys were the least penalized team in the league this year. The Raiders and Lions were the most penalized (even if penalties don't appear to be significant in the outcome of games, it is telling that the notoriously dirty Raiders and Detroit, which was embarrassingly chippy this season, accumulated the most fouls).

* Of course, especially stout defenses are still helpful. The Ravens and 49ers both have shots at the Super Bowl primarily because of the strength of their defenses (or, in the case of San Francisco, the astounding and league-leading +28 turnover ratio that continued in the upset against New Orleans). To oversimplify, next weekend features the Ravens and 49ers representing defensive primacy and the Giants and Patriots the power of offensive dominance. Should make for some enjoyable spectating!

Which division is the NFL's best?

The NFC North is arguably (in sports, what's inarguable, after all?) the best division in the NFL this year. There's a good chance both of the conference's wild card teams will come from it if Detroit is able to steal a big win against the Saints next week and Hanie is able to make things happen the way Cutler does. If the Packers are able to protect Rodgers against the Giant's front four in East Rutherford, it's not difficult to see Green Bay going 19-0. The 49ers have a soft enough schedule to conceivably finish the regular season 14-2, which will be enough to keep the Pack from making preseason games out of their last couple (although the Bears and especially the Lions could both benefit if the 49ers falter down the stretch--before one of them falls to their division foe in the divisional round and maybe the other in the conference championship).

For the NFC North to be so dominant feels unusual. As someone who learned the game while living in Dallas during the early and mid-nineties, I've seen "my" team (which I begrudgingly have to share with the rest of America!) take some tough breaks due to the strength of their division rivals over the years. Every division has its dog except for the two Easts. Talking to a friend last night who lives in the DC area, he suggested what I deem the Redskins (and Bills) "lost decade" was in large part due to the same (though it's hard not to argue that Dan Snyder's capriciousness deserves a lot of blame, too).

To give some relevance to the above, let's use it as a segue into the purpose of the post--creating an empirically determined ranking of the eight NFL divisions since the league tidily realigned itself in 2002 up through the end of last year. The following table shows regular season win percentage among the four teams in each respective division, after backing out all divisional play and excluding the handful of ties that have occurred over those nine seasons:

Division	Win %
1. AFC South	.567
2. NFC East	.556
3. AFC East	.548
4. NFC South	.526
5. AFC North	.503
6. AFC West	.481
7. NFC North	.448
8. NFC West	.370

No surprises in the way the rankings shake out, except perhaps for how far down the list this year's top division falls and that the AFC South rather than the AFC East is king of the hill. Detroit has just been really, really bad for a really long time (they were 37-107 from 2002 to 2010). That, and to a lesser extent the mediocrity of the Vikings, is why. And the Colts have been as stellar as the Lions have been terrible over the same period of time. It's not absurdly hyperbolic to say that Peyton Manning, almost single-handedly, lifted the division to the top. Without him, we're witnessing the division come crashing down. But hey, at least the Texans will finally get that elusive playoff berth and rid the league of its last postseason virgin.

The NFC West's showing is awful. That the Seahawks won it last year despite a losing record typifies what has been unending ugliness since Kurt Warner, Tory Holt, and Marshall Faulk (remember the "greatest show on turf"?) were at their best.

It's worth noting that the geographic dominance of the SEC that shows up in college football (those guys are blacker faster!) also exists to a noticeable extent in the NFL. The South and East divisions are better than the North and West divisions are in both conferences (the AFC North is somewhat exceptional, with two regularly good and two regularly not-so-good teams). I don't follow college football closely enough to have a sense of how much of a role, if any, geographic proximity to where they played in college ends up influencing where the bulk of new professional players sign, though, so maybe this is just coincidental.

2010 NFL regular season wins and stat correlations

With the Superbowl a day away, here are correlations between several favorite stats and wins during the 2010 NFL regular season. This isn't a sports blog, and I'm not making any audacious claims about being able to provide special insights. Just the raw correlations for entire teams here, next to the same for last year for comparative purposes:

Offense	2010	2009
Turnover ratio	.72	.69
Points scored	.71	.88
Team passer rating	.68	.81
3rd down conversion %	.64	.64
Time of possession	.61	.46
1st downs	.51	.70
Total yards gained	.49	.77
Yards gained per pass play	.49	.80
Run attempts	.48	.12*
Total yards gained per play	.43	.81
Run yards gained	.35	.04*
Pass/run ratio	(.31)	.02*
QB hits allowed	(.31)*	(.53)
Pass yards gained	.30*	.68
Sacks allowed	(.26)*	(.53)
Offensive penalty yards	(.11)*	.04*
Pass attempts	(.06)*	.14*
Yards gained per rush play	.05*	.09*
4th down conversion %	(.05)*	.25*
Defense
Points allowed	(.72)	(.68)
Rush yards allowed	(.56)	(.58)
Opponent's passer rating	(.54)	(.47)
Yards allowed per pass play	(.49)	(.57)
Total yards allowed	(.47)	(.56)
1st downs allowed	(.43)	(.45)
Total yards allowed per play	(.32)	(.54)
Sacks made	.30	.41
Run yards allowed per play	(.16)*	(.33)
3rd down conversion % allowed	(.13)*	(.23)*
Passing yards allowed	(.13)*	(.24)
4th down conversion % allowed	.03*	(.30)
Defensive penalty yards	(.01)*	.14*
Special Teams
Average kickoff return yards gained	.23*	.05*
Average kickoff return yards allowed	(.13)*	.15*
Average kickoff (kicking team)	.08*	.32
Field goal % made	.08*	.03*
Average net punt yards (kicking team)	(.08)*	.27*
Total penalty yards committed	(.08)*	.11*

* not statistically significant at 90% confidence

When I heard a sports writer in Chicago predicting that the special teams game would be a "slaughter", as the Bears are among the best and the Packers are notoriously bad, I thought "if the post from last year has anything to say, it's that that doesn't matter."

The most notable difference from a season ago, and a possible deviation from an ongoing trend in the NFL that has seen the passing game become increasingly determinative of success and the run game meaning less and less, is that teams like the Jets, Eagles, Bucs, and Chiefs that could move the ball on the ground fared pretty well. Arguably, these are mostly mediocre teams that ended up with winning records largely due to softness of schedule. But as Steve Sailer has pointed out, 2009 was an extremely pass-friendly season even by recent standards, and 2010 was more in line with the rest of the last decade.

Penalties and turnovers, penalties and turnovers, penalties and turnovers... Or how about "turnovers and turnovers"?

Data from the last two seasons correlates at .90, essentially meaning that over 80% of a stat category and its correlation with its team's number of wins is 'explainable' by looking at what occured the year before. That is, from an obviously limited sample of only two years, the numbers put up by successful teams in '09 were largely the same types of numbers put up by successful teams this season.

Modest proposal for the NFL postseason

Increase the playoff pool from twelve teams to sixteen. The controversy this year swirled around divisional winners hosting teams with better records than their own in the wildcard round, but more unsatisfying than the Saints (11-5) having to play in Seattle (7-9) or Kansas City (10-6) getting to host the Ravens (12-4), was the Giants and Bucs (both 10-6) being shut out altogether.

Since the league found the sweet spot with 32 teams beginning in 2002, the regular season win percentage for hosts is 57%. In wildcard games over the same period of time, it's just 53%.

This suggests that strong teams with good records that don't come out on top of their divisions are generally still competitive in the playoffs. This season, three of those potential Superbowl contenders--the Giants, Bucs (okay, a stretch), and Chargers (the Raiders being the other AFC entry if the proposed change were in effect this year)--didn't get in, while the unimpressive Chiefs and Seahawks did. To keep the host-and-be-hosted division rivalries relevant, though, division winners should still be granted a guaranteed berth and minimum #4 seeding. The baby gets split, and everybody is happy!

Well, not quite everybody. The biggest losers (although the teams' owners cash in on this 'loss') in this scheme are the #1 and #2 seeds, who forego first-round byes and are thus required to win four consecutive games instead of three in the postseason to be champions. But NFL brackets are more intelligently malleable than, say, the NCAA basketball tournament brackets are, so the top seeds still get the softest matchups--usually no more than nine wins--at home in the wildcard round. And the #2 seed is still guaranteed homefield until the conference championship, while the #1 seed still only gets knocked out if they lose on their own turf.

Parenthetically, it's really incorrect to describe the NFL postseason as operating under a single elimination bracket system at all, since the highest seed is always pared up against the lowest seed, etc, in each round, irrespective of the graphical bracketing imagery regularly used in (and then often necessarily revised) proceeding rounds. Indeed, this year the initial postseason brackets were 'incorrect' in both conferences (see right), due to only one of four division winners advancing to the divisional round.

This season, instead of enjoying first round byes, New England would've hosted Oakland, Pittsburgh would've hosted San Diego, Atlanta would've hosted Tampa Bay, and Chicago would've hosted New York. The only upset that would've seemed genuinely 'scandalous' in those four games would have been a Raider upset in Foxboro, but that of course raises the question of why a team with the best record in the NFL unable to beat a .500 team it is hosting when it counts should be accorded a freebie win to begin with anyway.

Black men are athletic, Hispanic women are not

In 2004, the GSS asked a question about self-assessed athleticism (and thanks to Jokah for alerting me to it). Conveniently, this is the same year interviewers were asked to rate respondents as being below average, average, somewhat above average, or considerably above average. Among those deemed to be remarkably thin, 27.5% responded that "athletic" described them well. Among those of normal build, it was 33.3%. For those overweight, 20.2%. And among the obese, 9.5%. So self-perceptions appear to be at least generally in line with reality.

The following table shows the percentages of people, by race and sex, who consider the adjective "athletic" either a good or very good descriptor of themselves:

	Athletic
Black men	59.5%
White men	39.7%
Hispanic men	36.3%
Asian men	25.9%
Asian women	25.6%
Black women	21.8%
White women	21.0%
Hispanic women	15.1%

Sometimes posts require no bloviating beyond the blog's tagline, and this is one of those posts. Color me loquacious though, because I'd still like to say a few words anyway.

Black men easily come out on top, followed by white guys, with Hispanics closely trailing them. This comes as little surprise to anyone who has played sports with blacks at a competitive level. They move quicker and jump higher, although the perception of black men as physically stronger than white men seems in my experience to be more of a conflation of general athleticism with upper body strength than an accurate reading of reality.

Men are more athletic than women are, except for Asians, where there is gender parity. Asian men are notorious for being bad at sports, tending to small and neither strong nor fast. I'm not aware of that stereotype existing for Asian girls, though I'm not aware of any particular Asian female prowess for athletics, either. The sample sizes for Asians are small (51 men, 49 women), so they should just be taken as suggestive in any case.

The rates of athleticism are even among white and black females, which probably has to do with corpulence among black women, who actually tend to have wider waists than black men do (among all other races, male waist size is larger).

I've played lots of soccer with Mexican men who are serious about the game (although the average Mexican guy doesn't seem to be particularly good at it--in the league games I've played, it's almost always the all white team I'm on against a team of likely illegal immigrants who speak broken English at best, and we always crush them), but the women who are there watching look to be in especially poor shape, with oozing tortilla flabbiness in abundance.

A few months back, a study was released suggesting that exercise may improve brain functioning. The implication that this is a formula for raising test scores and closing the achievement gap (more recess time for NAMs?) is standard blather from those antagonistic towards cognitive realism, but in my own personal experience, it is modestly beneficial. Specifically, my ability to focus is enhanced after I've worked out (unfortunately, I have to balance this with the realization that I simply don't lift as well and am more prone to tweaking in the mornings, especially within the first couple hours of waking up, so I generally do cardio in the morning and lift when I get home in the evenings).

Without any speculation on which way the causality arrow points, if there is an arrow at all, the percentages of people who describe themselves as athletic by intelligence follows. Respondents are divided into five groups forming a roughly normal distribution by wordsum score; Really Smarts (score of 9-10, comprising 13% of the population), Pretty Smarts (7-8, 26%), Normals (6, 22%), Pretty Dumbs (4-5, 27%), and Really Dumbs (0-3, 12%). To avoid the confounding factor of race, with blacks potentially skewing the correlation between athleticism and intelligence in an inverse direction, only whites are included. In a similar vein, only those 40 and under are considered, to avoid confounding from the elderly who may have considered themselves athletic in the past but no longer do so and who've also had a lifetime to stumble upon the definitions of various words:

	Athletic
Really smarts	34.3%
Pretty smarts	33.8%
Normals	40.4%
Pretty dumbs	38.4%
Really dumbs	44.3%

To the extent that there is a relationship, it does indeed appear to be slightly inverse (although not statistically significant). It is conceivable that people who don't have a lot upstairs are more likely to emphasize their physical abilities. It's also possible that athleticism and intelligence are unrelated. If this is the case, the fact that professional athletes tend to be more intelligent than the population at large (when race is taken into account) is presumably the result of higher IQ leading to better nutrition, more discipline in working out and mastering positions played, etc.

GSS variables used: ATHLETIC, SEX(1)(2), RACECEN1(1)(2)(4-10)(15-16), INTRWGHT

How predictive is the preseason?

One last NFL-related post before the season gets underway (okay, the NFC championship game rematch that have guys who love field position contests like yours truly hoping the Saints' win is a sign of things to come means the regular season has officially started). Playing poker at a friend's house, someone turned on the Royals' game just a few minutes before the Chiefs were to play the Eagles in preseason. My protests were met with assertions that the preseason is meaningless and thus not worth watching. I responded with the opinion that the NFL is always worth watching because, well, it's the NFL. I wasn't going to argue that the preseason was of little use in predicting how the regular season would turn out.

Still, I've heard forever that the preseason is not a portent of the regular season following it and want to make sure the claim is justified. NFL.com has preseason standings going back to 2006. I'm sure digging through the sports archives, I could find results going back much further than that, but four years is enough to determine, at least in the contemporary NFL, the preseason doesn't predict much. The correlation between a team's preseason and regular season winning percentages for 2006-2009:

2006: .02
2007: .16
2008: (.13)
2009: .05

Nothing approaching statistical significance in any of these seasons. Over the last four years, the Colts, arguably the top team over that span of time, won a total of four preaseason games--one per year. Hilariously, in 2008, the Detroit Lions were the only team to go undefeated through the preseason and also the only team to go winless during the regular season of the same year.

I hate to break it to Niners' fans, but there won't be any glory reclaimed in 2010. And for those counting the Colts out because they went without a win this preseason... okay, they are the odds-on favorite to win the Super Bowl this year, so I'll stop trying to act as though anybody puts stake in what transpires during exhibition games.

NFL seasons have become less predictable over time

With the NFL regular season a couple of weeks from commencement, predictions for 2010 are about to (dis)prove their worth. The prevailing mindset seems to be that a few surprises are inevitably in store, as has more-or-less been the case since the Colts clinched a first-round bye in the playoffs during the 1999 season, a year after finishing 3-13. Last year, of course, the Saints won it all after a decade of mediocrity.

How relevant does the idea of parity in the NFL remain relative to decades past? When the term "dynasty" is used, how far back in time must one go to apply it meaningfully? The Patriots of the early 2000s? The Cowboys of the early and mid-nineties? The 49ers of the eighties? Or all the way back to the Steelers of '74-'79, who won four Superbowls in six years? It's a question sports buffs could argue over indefinitely.

As I don't have a compelling qualitative case to make, I'll defer to the numbers and take the quantitative approach. The following graph shows the season-to-season wins correlation over time. That is, the r-value for the 2008-2009 seasons is computed by taking each team's number of regular season wins in 2008 and correlating them with the number of regular season wins each time had in 2009. The individual data points are provided in a table at the end of this post.


There are some expected year-to-year random fluctuations, but three broad periods emerge, each one successively defined less by steady performance season after season than the period before it. In the seventies, teams' regular season records consistently correlated at higher than .50. If you were a Steelers fan in 1974, you had strong reason to believe that the black and gold would have a very real shot at hoisting up the Lombardi trophy again next year. That's in contrast to the state of the game today--who is seriously predicting a repeat performance by the Saints in Arlington next February? (The odds-makers show them tied with the Cowboys as the second most likely team to win, behind the Colts; I'm highly skeptical).

After a couple of topsy-turvy years ahead of the players' association strike that severely disrupted the 1982 season, the 49ers helped bring a brief return to seventies-era consistency. By the late-eighties, the capriciousness of the Bengals (who had only won 4 games a year before Boomer Esiason came up a little short against Joe Montana in Superbowl XXIII) became relatively commonplace.

Year-to-year performance would hover around .40 from that period through the end of the nineties. Then, in 1999, pandemonium ensued! After leading the 49ers to a 3-1 start, Steve Young's career would come to an end at the hands, er, shoulders of Aeneas Williams, one of the greatest defensive backs in NFL history (I realize that assertion is controversial, but Young never played again, so it effectively did so). San Francisco would go on to lose all but one of their remaining 12 games, ending 4-12 a year after they had gone 12-4. The Colts, meanwhile, did the opposite, as Peyton Manning, in the manner of Troy Aikman a decade before (and then some), exploded onto the scene in his second year as a pro, leading the Colts to a 13-3 regular season after his disappointing 3-13 rookie year.

This is about the time "parity" became cliche (although it more accurately described perceived randomness rather than equality in teams' performance on 'any given Sunday'). No season before or after has ever outdone 1999 in jumbling things up from the previous year, but excepting 2008-2009, which was unusually consistent, the year-to-year correlation has floated around .25 ever since, repeatedly failing to constitute a statistically significant result at even 90% confidence.

Years	r-value
08-09	.56
07-08	.21
06-07	.26
05-06	.29
04-05	.26
03-04	.24
02-03	.20
01-02	.38
00-01	.19
99-00	.36
98-99	.01
97-98	.50
96-97	.35
95-96	.44
94-95	.42
93-94	.26
92-93	.49
91-92	.32
90-91	.40
89-90	.43
88-89	.44
87-88	.33
86-87	.30
85-86	.69
84-85	.68
83-84	.51
82-83	.47
81-82	.28
80-81	.05
79-80	.33
78-79	.68
77-78	.56
76-77	.79
75-76	.56
74-75	.64
73-74	.61
72-73	.58
71-72	.50
70-71	.63
69-70	.39

Motley mix

- I'm not aware of any reason to suspect Armando Galarraga is not a naturally gracious and understanding athlete, but what I do suspect is that on the long road of sports history, umpire Jim Joyce's blown call will accentuate Galarraga's profile, not diminish it. Twenty pitchers have thrown perfect games, and over the last two decades, it has occured, on average, about every other year (and twice this season alone!). Among the general public, Galarraga's name would have otherwise probably been flushed down the memory hole in a few years' time, but now his name will be invoked every time reference to the roster of perfect pitchers is made as the guy who was cheated out of inclusion on it.

- McDonald's new gay ad beautifully illustrates (unintentionally, of course) the West's apparent moribundity. An old lady-killing father thinks he is sharing a moment with his son that his son will someday share with the father's grandson. But alas, the son has no use for his father's mores and will never himself become a father:



It works on so many levels.

- The activists on the Turkish ships attempted to run a clearly demarcated blockade. They're fortunate the IDF didn't send the entire flotilla to the bottom of ocean, which would've been a legitimate response against those aiding a declared national enemy. Israel is not a signatory of the Law of the Sea Treaty, so the country is not legally bound to treat putative "international waters" as vast neutral spaces where their perceived interests cannot be fully acted upon.

- There should be a brand of casual business clothing that sells itself on the durability of the string that attaches the waist button to its pants. I'd pay a premium several times the total cost of using fishing line in place of regular yarn for a pair of slacks I could be confident that I'd never pop the button off of. Sewing it back on is so much of a hassle I usually just (lazily) use it as an excuse to buy a replacement pair.

Passing, rushing, and winning in the NFL since 1969

In January, after having a little fun with team stats for the 2009 NFL season, I looked at the correlations between success (wins) and per-play passing and per-play rushing throughout the early years of this century. The trend is clear--a strong passing game does a top-tier team make. Running is far less determinative.

But rule changes and a paradigmatic shift away from raw power to pure speed (the fullback, a linchpin position as recently as Daryl "Moose" Johnston of the nineties' Cowboys, is all but dead today) have increasingly led to the predominance of passing over running. This has not always been the case.

That has been my conception, anway. To see how well it meshes with reality, I ran the numbers extending all the way back to the 1969 season. The following table traces the last four decades, showing the correlations between winning and both passing yards per attempt and running yards per attempt by regular season:

Year	Pass	Run
2009	.80	.09*
2008	.48	.15*
2007	.76	.24*
2006	.44	.10*
2005	.60	.40
2004	.56	.45
2003	.67	.07*
2002	.50	.11*
2001	.39	.13*
2000	.47	.51
1999	.53	.12*
1998	.75	.32*
1997	.37	.27*
1996	.40	(.06)*
1995	.46	.28*
1994	.55	(.05)*
1993	.55	.34*
1992	.70	.08*
1991	.63	.33*
1990	.56	.05*
1989	.64	.04*
1988	.56	.16*
1987	.52	.15*
1986	.49	.03*
1985	.46	.13*
1984	.57	.09*
1983	.32	.42
1982	.51	.22*
1981	.21*	(.07)*
1980	.58	.19*
1979	.54	.11*
1978	.72	.09*
1977	.63	.30*
1976	.70	.29*
1975	.77	.34*
1974	.60	.16*
1973	.66	.47
1972	.50	.51
1971	.34*	.12*
1970	.57	.24*
1969	.48	(.24)*

* Not statistically significant at 95% confidence

The data dispute the preceding narrative. There is a lot of variation in the strength of the correlations from season to season, as is of course expected given that defense, special teams, penalties, schedules, etc are not taken into account. Still, passing has consistently been tied more tightly to success than running has been. In only three of the last 41 seasons has the relationship between rushing yards per attempt been more closely related to winning than passing yards per attempt has, and in each of those years--1972, 1983, 2000--running's advantage has been small.

The 2009 season, deemed the year only passing mattered, added an exclamation point to this observation. Over the last three decades, passing's importance has risen marginally, correlating with wins at .57 on average durings the 00s, from .52 in the eighties (.55 in the nineties)--but in the seventies, the average was .62. It's nothing new.

If, despite the reliably delivered claims coming from professional commentators during the playoffs to the contrary, passing matters most, why isn't the pass-to-run ratio more lopsided than it is?

Turnovers are one reason. In recent years, interceptions constitute about two-thirds of them, and some portion of the remaining one-third, coming in the form of fumbles, are lost by quarterbacks getting hit or receivers losing the ball after the catch. In 2009, a team's turnover balance (takeaways minus giveaways) correlated with games won at .69.

A one-dimensional approach putatively gives a big advantage to defenses as well--color commentators regularly describe running plays mid- and late-game as attempts by offenses to keep the opposing defenses "honest".

That said, I do wonder if, over time, there has been a shift toward more yards earned through the air relative to those on the ground. If passing's primacy is nothing new, maybe throwing the ball more is. Yet the diminution of the 1,000 yard rusher and the new benchmark of 2,000 yards in a single season suggests more, not less, yardage is being earned on the ground than before. I'll see what the history shows and present here.

More on passing, running, and winning in the NFL

++Addition++Steve offers more on 2009, deeming it the year only passing mattered. He wonders whether or not the NFL's popularity will decrease if a successful passing offense and a winning record continue to become increasingly synonymous with one another.

It's my impression that football votaries like smashmouth, low-scoring field position games a lot more than casual fans do. I'd guess more than a few of those casual fans would judge a typical 48-31 game more thrilling to watch than a 9-6 game. Assuming I'm in it to see the most competitive sixty minutes possible, I wouldn't--I'd take the second game for sure. But I'll still follow the NFL as high-scoring, pass-happy games become more common, whereas casual fans (especially women) will be unlikely to stick around if this year's Jets became the NFL archtype. So I'd guess the current trend will be good for business.

To the extent that passing is more important in the regular season than it is in the post-season, it's unfortunate as far as the league's level of popularity is concerned--the other way around would be more desirable. More indoor arenas and closed stadiums might help.

---

Steve wondered if the pattern in 2009 of passing's dominance over rushing as a determinant of success was carried over from the season before. It could have been a fluke year, or the beginning of a secular trend. The following table shows the correlations between winning and both passing and running yards per attempt by regular season going back to 2002:

Year	Pass	Run
2009	.80	.09*
2008	.48	.15*
2007	.76	.24*
2006	.44	.10*
2005	.60	.40
2004	.56	.45
2003	.67	.07*
2002	.50	.11*

* not statistically significant at 90% confidence

In 2008, the pass-run gap was less pronounced than in 2009, but still significant. However, 2007 was similar to the just-concluded regular season. As we move back in time, passing maintains the upperhand, but not as overwhelmingly so. In 2004, when the playoff-bound Falcons (Vick alone ran for nearly 1,000 yards that year), Steelers (Staley-Bettis one-two punch), and Jets (Curtis Martin in his best season before complications with a knee injury forced him into retirement) built their offenses around the running game, rushing came within striking distance of passing in importance.

As Steve has discussed, the nimble, impatient quarterback who's comfortable being flushed out of the pocket to run is not the future of football, it is the past. The nearly total domination of passing relative to running today suggests that a new paradigm is emerging, where the running game is clearly superceded in importance by the ability to move the ball through the air.

If a football votary is up for investing a little time in it, it'd be interesting to see how the pass-run dynamics correlate with success going back several decades. NFL.com's stats on per-play averages extend back over 60 years, so the data are there.