Saban's Hyperbola: Analyzing Alabama's Long FG Attempt

Way late to the party here, but let's do this because it's so interesting. As every football fan on the planet knows, Alabama attempted a 57-yd FG with 1 sec to play in regulation against Auburn. The kick fell short and was returned for a stunning game-winning TD. The consensus analysis seems to be that the FG attempt wasn't necessarily a bad decision, but the big mistake was that Alabama was not prepared with appropriate personnel to cover a potential return.

Let's look at the FG decision more closely. I won't use the WP model, but instead apply some math and logic. There were three options for Alabama:

1. Kneel
2. Hail Mary
3. Attempt the FG

Let's make some assumptions. First, OT is a 50/50 proposition. Alabama was favored in this game, but Auburn was playing strong. Plus, OT is a bit of a dice roll to begin with. Second, Hail Marys (Maries, Mary's?) from that range are probably no more successful in college than they are in the pros, which is around 5%. Lastly, for the sake of the argument, let's say there is zero chance of a defensive TD return on the Hail Mary.

We don't really know the probability of a successful FG attempt or the probability of a successful return or block & return from a range like that, especially in college ball from a kicker without many attempts. But let's set that aside for a moment.

Should You Kick a FG on 3rd Down?

With the game on the line, coaches are fond of attempting a FG on 3rd down in case of a bobbled snap. The rationale is that in case of a bad or bobbled snap, the holder can fall on the ball and the kick can be reattempted 8 yards deeper. Maybe that made sense in 1974, but I'm pretty sure it's a bad idea now.

Unless you're inside the 10 kicking on 3rd down isn't a good idea. Even a gain of 1 yd improves FG prob more than the chance of a bad snap.
— Brian Burke (@Adv_NFL_Stats) December 2, 2013

Admittedly, I wrote that just based on my familiarity with the relevant numbers, so I thought I'd do the legwork. FG% improves with every yard closer a team gets. Every yard matters. In fact, every yards matters to the tune of 1.6% per yard when the line of scrimmage is between the 35-yard line and the 10-yard line.

Yesterday, Keith looked at this kind of situation in the context of the CHI-MIN game, and his results suggest the same conclusion. This post will examine play outcomes on 3rd down when the game is on the line and teams are in deep FG (attempt) range, and compare them to the likelihood of a bad snap or hold.

Altitude and Field Goals

Last season I looked at the effect of temperature on field goal success and saw that a 30-degree difference is approximately worth 5 yards of kick distance. A 40-yard attempt in 30 degree weather is like a 45-yard attempt in 60 degree weather. Much of the effect can be attributed to the increased air density in colder air. But what about altitude? How does the thin air of Denver's Mile High Stadium affect field goal success?

When it comes to altitude, there's Denver's 5,200 feet and then there's everywhere else. Phoenix is the next highest at about 2,000 feet, but it's almost twice as close to the sea level as it is to Denver. To compare apples to apples as much as we can, I compared Denver's FG success with that at other outdoor stadia. I excluded Arizona for the purposes of the comparison, and only included kicks in moderate temperatures from 41 to 80 degrees.

Deadspin/Slate: The Effect of Eliminating Kickoffs

The guys at Deadspin and Slate asked me to write up how Goodell's suggestion that kickoffs be replaced by punts would affect the game.

Here's the Slate link. Here's the Deadspin link.

...With proposed rule changes like these, I ask myself, "What if things had always been this way? Would we want to change from that to the way things are now?" If football didn't have the extra point—an odd play that's meaningless to game outcomes 99.9 percent of the time—would we want to invent one? Probably not.

In this case, if we'd always started the game with a punt, would we want to invent the kickoff? It's not so clear. With the yard line of the kickoff now at the 35 and as placekickers continue their trend of booting the ball farther, it won't be long before every kickoff is a touchback. The kickoff might soon become like the extra point—a boring formality...

I strongly recommend Keith's post on the subject too.

The Extra Point Must Go

This week's article at the Post asks What's the point of the extra point?

 The extra point is something left over from gridiron football’s evolution from rugby. Originally, the ‘touchdown’ in rugby was less important than the ensuing free kick, and the points given for the touchdown and the ‘point after try’ varied during football’s early history. Today’s extra point is a vestige of football’s rugby roots. It’s football’s appendix–inconsequential, its original purpose uncertain...and safe to remove.

The Field Goal Likelihood Nexus

I'm not sure why meaningless things like this fascinate me so much. I was doing some experimentation modeling how often offenses are normally able to score given the various down/distance/yard line combinations. I always plot the results to make sure they make sense.

In this case I was looking at the probability of ending a drive with a made field goal in 2nd and 3rd down situations. (Second and third down modeling is especially challenging because there are fewer cases of each successive down. Plus there is an entire other dimension to consider--to-go distance. By comparison, first downs are almost always 10 yards to go.) After seeing the plots I thought there was clearly something wrong.

You'd expect that having fewer yards to go would lead to scoring more often, but once you think about it that's not always true when looking at only field goals. For most of the field, having fewer yards to go is better, but once a team passes a certain point, having more yards to go means it's more likely that a drive will stall inside field goal range.

Punting From Your Own Goal Line

Recently, we looked at how teams are too conservative with play calling when backed up against their own end zone. The main idea is that coaches want to give their team more room, and in particular, they want to give their punter more room so he does not have to stand in the back of the end zone. But, are punters actually more efficient with more room between them an the end line?

Let's look at average EPA on punts based on yards from goal. Specifically, we're going to look at inside the 3-yard line vs outside:

Kickers Are Getting Better and Better

This past Sunday we saw the all time FG distance record tied for the second time in a year. And it wasn't indoors or even in Denver. I've previously written about how FG accuracy has improved even as attempt distances have increased., but even in the last few years kicking accuracy at long distances has improved significantly. This trend shows no sign of slowing, and it has significant implications for the sport.

In an analysis of the previous overtime format, I noted the following:

In 1974, the league FG% was 60.6%. This year, it was 84.5%. And that even masks how much kickers have truly improved. In 1974, 36% of all FG attempts were from 40 yards or beyond. In 2008, the figure was 41%. These days, teams aren’t looking to get inside the 25 for a field goal attempt, they’re just hoping to get inside the 40. Getting a quick score in overtime has become a far easier proposition. Field goals have gradually warped NFL football. In 1974, there were 3.0 FG attempts each game compared to 3.9 in 2008, a 30% increase.

How Important is Opponent Starting Field Position?

Earlier this season, I wrote a post about how San Francisco did an excellent job limiting their opponent's starting field position.  After a similar dominant performance against Pittsburgh in Week 15, I decided to revisit this topic.  This year, the 49ers lead all teams in average starting field position for their opponents; their opponents, on average, start at their own 24.4 yardline.  The next best teams? New England Patriots and Green Bay Packers.  In fact, this year, there is a 0.73 correlation between win percentage and average opponent starting field position.

But let's go back.  Since 2000, we see a 0.45 correlation between win percentage and average opponent starting field position.

Sebastian Janikowski Sinks The Bears From Afar

If there was ever a game prepared for a kicker, it was Sunday's Oakland Raiders contest against the Chicago Bears. The Raiders brought an offense with big play potential but with a low success rate against a Bears team among the league leaders in preventing successes. Many situations in football call for the coach to go for it on fourth down more often than we see in practice. This game, however, presents one scenario in which it is often smart to take the points if they're available -- the combination of a misfiring offense and a brick wall defense could tilt the field position game beyond reversal.

Of course, getting the three points on a field goal attempt isn't so easy as just calling the kicker and his support team onto the field. Field goals are risky propositions -- anywhere past the 30-yard mark and we encounter at least a 10% chance of failure. The lack of a capable field goal kicker could tilt the equation right back to supporting repeated fourth down conversion attempts.

Does FG Accuracy Decline In Clutch Situations?

Like most other Baltimore fans, I was disappointed at the end of the most recent Ravens game when kicker Steve Hauschka missed a 44-yard field goal that would have capped a dramatic comeback. What made it worse was that I had to suffer through the usual nonsense from the local sportswriters about how Matt Stover, the popular long-time Ravens kicker until released this year, would have undoubtedly made that kick.

The jury is certainly still out on whether Hauschka is any good, but let's keep one thing in mind. NFL kickers as a whole only make kicks from that distance 70% of the time(including blocks). We simply don't remember all the missed field goals in the first quarter, or when our favorite team is already 17 points ahead or behind. The ever-clutch Stover? His career accuracy from that range was...70%.

But then I wondered whether FG kickers are affected by the game situation. Do their nerves get rattled? Are kickers less accurate in clutch situations when the game is on the line?

Field Goal Kickers

I recently took a look at special teams (ST) and its importance in winning. One of the most important, if not the most important, players on ST is the field goal kicker. No one else has such a direct and solitary impact on points scored. In this post, I'll look a little closer at the impact a kicker can make on the win-loss record of his team.

The relative importance of each dimension of the game, including ST, is estimated in a regression on regular season wins. Each variable is in terms of team efficiency (yds per attempt) and is standardized. The ST variables are relative to the league average for similar situations. For example, the FG/XP scores are relative to kick distance and the average success rate for each distance (1).

The results are summarized in the table below.

Variable	Std.Coeff.	P-Value
O PASS	1.26	0.00
D PASS	-0.81	0.00
O RUN	0.47	0.00
D RUN	-0.47	0.00
O INT	-0.63	0.00
D INT	0.60	0.00
O FUM	-0.33	0.07
D FFUM	0.36	0.02
PEN	-0.41	0.01
FG/XP	0.34	0.00
KICK	0.44	0.00
K RET	0.07	0.64
PUNT	0.23	0.12
P RET	0.27	0.10
r-squared	0.79

The results above can be interpreted as follows. Each coefficient indicates how many additional regular season wins a team can expect, on average, per standard deviation above average. For example, if a team is completely average in every facet of the game, it can expect to win 8 games. But if a team is average in every facet except offensive pass efficiency, in which it is 1 standard deviation above average, it can expect to win 8 + 1.26 = 9.26 wins.

The best kicker in the league (#1 out of 32) would typically be in the top 96th percentile, which is very close to two standard deviations above average. Therefore, the best FG kicker in the league would normally be worth 2 * 0.34 = 0.68 added wins in a season.

It's hard to imagine many other positions, other than the starting QB and RB, that have such a large individual impact on a team's record.

Importance of Special Teams

In earlier posts I claimed that special teams could be neglected in a prediction model of wins because big special teams plays tended to be chaotic--largely random and non-repeatable. I think I may be wrong.

I can defintely say now that special teams (ST) retrospectively explain a good deal of variance in team records. But I'm not so sure it can help predict future ST performance, and therefore future wins.

The biggest challenge in analyzing ST stats is that they are difficult to measure. For example, consider a team that is frequently punting from midfield or the opponent's 40 yard line. They would likely have poor net punt yardage compared to teams that punt from their own territory more often. All of football is dependent on the situation, but special teams are in particular.

The website Football Outsiders has a potential solution. They grade each play according to the situation and compare each team's performance against the league average in the same situation. They call this measure Value Over Average (VOA). They go a step further and factor in a correction for opponent strength which results in Defense-adjusted VOA (DVOA). To be honest, I'm not sold on D/VOA as the best measure of team performance, but it does take situation into consideration on a play-by-play basis, which is espeically handy for special teams.

I was able to gather the D/VOA stats for special teams from the 2003-2006 regular seasons (n=128). I then added it into the team efficiency model which estimates team wins based on each team's efficiency stats of running, passing, turnovers, and penalties. I normalized each variable in the model, so that their regression coefficients could be directly compared to one another.

The baseline efficiency model, without ST data, results in an r-squared of 0.73. Including either ST DVOA or ST VOA in the model increases the r-squared to 0.77. The regression results are shown in the table below.

Variable	Std.Coeff.	P-Value
O PASS	1.27	0.00
D PASS	-0.80	0.00
O RUN	0.46	0.00
D RUN	-0.44	0.00
O INT	-0.53	0.00
D INT	0.57	0.00
O FUM	-0.40	0.02
D FFUM	0.44	0.01
PEN	-0.39	0.01
ST DVOA	0.68	0.00
r-squared	0.77

The results above can be interpreted as follows. Each coefficient indicates how many additional regular season wins a team can expect, on average, per standard deviation above average. I was surprised by how strong a variable ST DVOA turned out to be. It's standarized coefficient is 0.68, which is third only to offensive and defensive passing efficiency. If true, that would mean that the best ST squad in the league (about 2 standard deviations above the mean) is worth about 1.4 additional wins, on average.

I thought that a lot of that strength may be due to field goal kicking, which has the most direct impact on the score. So I reran the regression with each component of special teams broken out: FG/XP kicking, kick offs, kick returns, punts, and punt returns.

Variable	Std.Coeff.	P-Value
O PASS	1.26	0.00
D PASS	-0.81	0.00
O RUN	0.47	0.00
D RUN	-0.47	0.00
O INT	-0.63	0.00
D INT	0.60	0.00
O FUM	-0.33	0.07
D FFUM	0.36	0.02
PEN	-0.41	0.01
FG/XP	0.34	0.00
KICK	0.44	0.00
K RET	0.07	0.64
PUNT	0.23	0.12
P RET	0.27	0.10
r-squared	0.79

The standardized coefficients show that kick-off and kick coverage performance (KICK) is the most important (in winning) of all the components of ST. But kick return (KRET) is the only non-significant variable, which is puzzling. Why would kick-offs be so important if kick returns don't matter? This might indicate a shortcoming of the DVOA system.

Punt and punt return performance are marginally significant, but the signs of the coefficients make sense and they are relatively symmetric. So we can be confident they are relevant but their true coefficients may not precisely as indicated by this data set.

To simplify the results, I computed the relative strength of each of the standardized coefficients in terms of percent of the total strength of all variables.

Variable	Importance
O PASS	19%
D PASS	12%
O RUN	7%
D RUN	7%
O INT	9%
D INT	9%
O FUM	5%
D FFUM	5%
PEN	6%
FG/XP	5%
KICK	7%
K RET	1%
PUNT	3%
P RET	4%

So according to this analysis, special teams accounts for about 20% of the game in terms of winning and losing. In a way, this is disproportionately strong. ST plays comprise far fewer than 1 in every 5 plays on the field. GMs may want to take another look at how much they're paying their punters, kickers, and returners. Perhaps the league is noticing the importance of ST evidenced by the recent attention return specialists have received in the draft.

ST is a considerable part of the game. It retrospectively helps explain why teams won. The question remains, however, if prior ST performance indicates future ST performance, and if it is predictive of future wins.