Implications of a 33-Yard XP

The NFL is experimenting with a longer XP this preseason. XPs have become so automatic (close to 99.5%) that there no longer much rationale for including them in the game. The Competition Committee's experiment is to move the line of scrimmage of each XP to the 15-yard line, making the distance of each kick 33-yards.

Over the past five seasons, attempts from that distance are successful 91.5% of the time. That should put a bit of excitement and drama into XPs, especially late in close games, which is what the NFL wants. But it might also have another effect on the game.

Currently, two-point conversions are successful at just about half that rate, somewhere north of 45%. The actual rate is somewhat nebulous, because of how fakes and aborted kick attempts into two-point attempts are counted.

It's likely the NFL chose the 15-yd line for a reason. The success rates for kicks from that distance are approximately twice the success rate for a 2-point attempt, making the entire extra point process "risk-neutral." In other words, going for two gives teams have half the chance at twice the points.

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.

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.

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.

Temperature and Field Goals

As a pilot, I'm familiar with the effects of weather on things hurtling through the air. Many people intuitively sense hot, humid air as thicker and heavier, but the opposite is true. Warm air, as we all learned in 5th grade, is less dense than cold air. And the water molecules that make air humid, for some reason I've long forgotten, actually spread all the other molecules out, creating even thinner air. Aviators are wary of the Four H's--hot, humid, high (elevation), and heavy--things that can drastically alter performance and make takeoffs and landings a challenge.

Planes, and jet planes in particular, love cold dry air. The dense air helps engines work efficiently, and it helps the wings produce lift, making for shorter takeoffs and slower landing speeds. Baseballs, on the other hand, love the Four H's. Fans of our national pastime are well aware of the fact that home run rates peak in the hottest months of the season, and that balls tend to fly out of the park in Colorado.

Field goal kicks are affected by the same factors as anything else flying through the air--wind, temperature, and even altitude. In this post, we'll take a look at how temperature affects field goal success.