Penalties in Football
In Week 2 of the NFL season, the New York Giants played against the Washington Football Team. At the beginning of the first quarter, the Giants drove the ball down the field near the end zone.
The Giants were faced with a 2nd and 12 from the Washington 16-yard line, and then this happened:
The referees threw a (horrible) flag for Roughing the Passer, giving the Giants a first down from the 8-yard line. Had the referees refrained from throwing a flag, the Giants would have been faced with a 3rd and 12. Scoring a touchdown would have been extremely unlikely from this position. However, the referees threw the flag, and two plays later the Giants scored a touchdown.
Penalties have a large impact on scoring.
Football spectators know that the impact of penalties is significant, but it is interesting to think about quantifying the exact impact of penalties. Fortunately, there is a framework for that: Expected Points Added (EPA).
I’ve written about EPA before, but in case you are unfamiliar, EPA models the expected points for a team given its field position, down and distance, and the clock. When a team has the ball 1st and 10 at the 50-yard line, its expected points are ~2.5. If, after the next play’s result, the team’s expected points move to 3.0, the team gained a half of a point on the play. EPA is basically the football equivalent of Strokes Gained in golf.
What is the EPA of a penalty? Well, it depends on the penalty:
Example interpretation: On average, Roughing the Passer adds more than a point to a team’s expected points on the possession. That is impactful! For reference, a 15-yard gain on a 1st and 10 from a team’s own 25-yard line is worth ~0.82 points gained.
One takeaway is, “Whoa, penalties are significant. Referees better make the right calls.” I agree! But I want to focus on a different angle.
When analyzing NFL games, you should be mindful of penalties and incorporate them into your process. For example, if you like to bet on how many points will be scored in a game, analyzing expected penalties is worth your time! If one referee crew notoriously throws a barrage of Unsportsmanlike Conduct flags, you can expect a higher point total in that crew’s games than in the average NFL game.
You can also consider the likelihood of Defense Pass Interference penalties based on the routes a team runs:
It is easy to become overwhelmed by the ocean of information you must factor into a well-built model. Thus, prioritizing high-impact factors is essential. Penalties qualify as high-impact factors…
Penalties in Golf
When a golfer finds a penalty hazard, she is assessed a full one-stroke penalty. Penalties have a significant effect on scoring. But depending on the design of the hole, penalties are not always within the possible range of outcomes.
Some golf holes do not have penalty areas, or the penalty areas are so distant from the intended area of play that finding a penalty area is highly, highly unlikely.
Check out Justin Thomas’ ninth hole during Thursday’s round of the CJ Cup in Las Vegas this past week:
Justin hit his tee shot far off line, and his ball settled in between a few rocks. He attempted advancing his ball from the rocky terrain a few times before accepting a penalty shot and dropping his ball in a more favorable location.
Now here is the question: If Justin hit an identical tee shot on every PGA Tour hole all season, would the penalty be identical across holes?
Of course not! On some PGA Tour holes, spraying a drive 40 yards off target would not result in a (significant) penalty. Therefore, when projecting a player’s future performance, you must consider how a player’s skill set aligns with the characteristics of the future set of holes.
Many people in the golf prediction space lean heavily (or exclusively) on Strokes Gained numbers to arrive at predictions. But Strokes Gained numbers are not apples-to-apples comparisons across golf courses. An errant shot that results in a double bogey at one golf course might only result in a bogey at another golf course. Strokes Gained fails to account for differences among golf courses.
This is actually one of the reasons I had publicly expressed optimism about Dustin Johnson’s prospects at Whistling Straits for the Ryder Cup. Dustin is a long driver of the golf ball, but he is not one of the most accurate drivers on Tour. In 2021, he found a penalty hazard on more than 2.5% of his tee shots, which ranks well above Tour average.
At Whistling Straits, a tee shot must travel far off line to find a penalty area. Additionally, penalty strokes are less impactful in the Ryder Cup format (match play) than in stroke play. If a player scores a high number like a triple bogey in match play, the result is no different than if he had scored one stroke worse than his opponent scored. Essentially, match play trims off a player’s worst scores.
Thus, I did not anticipate Dustin Johnson would find many penalty areas at Whistling Straits, and even when he did, the impact would be minimized by the format, especially with the presence of a partner.
Hitting from Penalty Areas and Nonlinearity
“Should I try to hit a shot from this lie or should I accept a penalty shot?” is a common problem golfers face in tournament play. Quantifying the appropriate decision can be challenging. Arriving at the correct answer involves an understanding of how much risk is involved in attempting the shot versus how much reward is reaped by successfully executing the shot.
So I’ll offer a Rule of Thumb.
Recall this visual from a previous piece I’d written. The visual is pulled from an excellent Data Golf article:
The graphic demonstrates the concept of nonlinearity. Expected score does not decrease with distance from the hole in a linear fashion. The difference between having 150 yards to the hole versus 160 yards to the hole is not as large as the difference between having 20 yards to the hole versus 30 yards to the hole. As you approach the hole (towards the left of the graph), expected values begin to drop rapidly.
So if a player’s ball is wedged between two rocks and he is deciding whether to attempt the shot or to accept a penalty, “Hit the shot” is more likely the correct decision when he is close to the hole versus when he is far from the hole.
During Friday’s round of the CJ Cup, Brooks Koepka’s golf ball rested in a poor, risky lie on his first hole. The ball was 65 yards away from the hole:
By attempting the shot, Koepka had a legitimate opportunity to advance the ball near the green and drastically reduce his expected score. By attempting the shot, Koepka had a legitimate opportunity to reap a sizable reward.
In the previous section, I’d shown Justin Thomas in a similar situation, except his ball was 204 yards away from the hole.
I do not want to suggest that Justin Thomas’ decision to attempt a recovery shot was wrong, but I do want to suggest that Koepka’s decision was more favorable than Thomas’.
There is more payoff to attempting a risky shot from a penal location that is close to the hole than from a penal location that is far from the hole.
Correction*****
In last week’s edition of Finding the Edge, I’d included a section about the Official World Golf Rankings (OWGR). I had pointed out that Brooks Koepka’s total events played will fall below the OWGR minimum threshold (40 events), which means Koepka will become unranked. Many of you pointed out that I was mistaken. I was.
Koepka will not become unranked. Rather, points from fewer than 40 events will contribute towards his numerator of the OWGR calculation, while his divisor will remain at 40. Without going into the weeds of the OWGR calculation, I’d expect Koepka’s ranking to drop as he falls below 40 total events, though the impact is not too severe.
To avoid my mistake, I could have checked the world ranking of a player who has played fewer than 40 events over the last 116 weeks yet remains ranked (like Tiger Woods or Akshay Bhatia). I should have, and honestly it was a pretty dumb mistake. But it will not be my last, and I genuinely appreciate those who corrected me!
Anyway, I tweeted this last Thursday before play commenced:
So at least I get some things correct:
Contact/Feedback
Email: Joseph.LaMagnaGolf@gmail.com
Twitter: @JosephLaMagna
Other Content from this Past Week
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Some progress in professional baseball:
I don’t want to be overly critical of the best professional football coach of all time, but he does make some questionable in-game decisions:
A UFC coach came under fire (and apologized) for aggressive coaching during his athlete’s fight on Saturday. You can decide for yourself whether the actions warrant an apology. Video of the incident is clickable below:
