In my recent posts on the Maurice Jones-Drew kneel-down and the Belichick 4th down decision I cited a few stats about how likely an offense that needs a touchdown to tie or win is to score one with about 2 minutes remaining in the game. Normally I like to back up obscure stats like that with some firmer context, and I was finally able to get around to it for these numbers.
The chart below graphs the percentage of time a team that needs a TD, defined as being down by 4 through 8 points, gets a TD on its current drive given a 1st down at various field positions with 2:00 +/- 15 seconds left. (I know that's quite the run-on sentence, but I don't know how else to say it.)
It's remarkably linear. I'm somewhat surprised how unlikely offenses are to get the TD inside the 20. A lot of that is sample size. Teams are more and more likely to be stopped the closer you get to the end zone, so the number of cases gets progressively smaller. But two-minute drills are typically characterized by 70-yard drives, not 20-yard drives, so I'm more interested in the scoring rates at the other end of the graph.
The next graph looks at teams that need just a field goal with two minutes left, defined by teams trailing by 1, 2, or 3 points. The graph plots the percentage of drives that result in either a field goal made or touchdown. Field goal success rates are charted here.
Again, the plot looks linear, but probably less so toward FG range. The noise in the data increases toward the end zone here as well. For example, there are 6 cases in the 6-10 yard line bin, and two of them were interceptions resulting in a 67% success rate. Teams inside FG range with 2 minutes to go wouldn't necessarily be happy to settle for FG attempts. With that much time on the clock, the opponent would have plenty of time to respond with their own score. Here again, however, I'm mostly interested in the longer drives that typically eat a good deal of clock.
Edit: Here is a post from last year with graphs for all drives in all game situations. It's interesting to compare and see just how much more often teams can score when their back is against the wall. They can use all four downs and turnovers are no more costly than a stop. It makes we wonder whether teams should play with that kind of abandon all game long.
Note: Data are from all NFL games from the 2000 through 2008 seasons.
The Two-Minute Drill
By
Brian Burke
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Excellent work.
Do these graphs take timeouts into context? I don't know how much time is usually saved by an offensive team taking a timeout, but suppose it is 15 seconds. In other words, a team with 3 timeout effectively has 45 more seconds with which to work. This data would seem more complete if it would at least list the average # of timeouts that an offensive team starts out with. So if the average offense gains possession with one timeout, then a team with 3 timeouts and 1:30 to work with could use this chart to determine its probability of scoring. A team with 2:00 and zero timeouts probably has to tweak its chances downward, but a team with 3 timeouts would tweak upward.
To that point, I would expect a team taking over with 2:01 left of the clock to have a substantially higher success rate than a team with 1:59. Obviously the former has the 2-minute warning with which to work.
In closure, I'm surprised by these numbers. I thought that a team down by 4-8 points would score 10, maybe 15 percent of the time under these circumstances. These results are counter-intuitive, but obviously far more accurate than my own "gut.
I meant to mention that. No, unfortunately this does not factor in varying numbers of timeouts remaining. Consider it an average of a typical number of TOs left. We know more timeouts is better, and fewer is worse, but I can't say exactly how much with out a much, much deeper analysis.
People were dismayed at the TD % you used for the Colts/Pats if the Pats were to punt but it makes sense: Off the top of my head I can think of 3 games this year (SD/NY, Cin/Bal, Minn/SF) that ended just that way. I bet I'm skipping one or two and I bet just as many teams failed to score, but that's what the numbers say will (would? should?) happen.
Glad your blog got some exposure today. A great site.
In the absence of a definitive statistical analysis, it would seem easy enough to conjure up an intuitive guess. My gut instinct is that the average # of timeouts would be no more than one, since the team getting the ball may have used all of its timeouts on defense. Then perhaps use that to apply incremental adjustments.
I was surprised that the percentages are this high. Awesome work. I clearly overestimated the effects of time and cover schemes, while underestimatng the effect of using four downs instead of three. But as many have discovered, most everyone underestimates the advantages of using four downs.
Yes....Thank you for posting this. There was a whole lot of talk today and I saw your site referenced in quite a few different places.
It seemed like you were the lead person in the go-for-it debate. I sort of believe that eventually teams will play more 4 down football. At some point, the tipping point will be reached and the default will be to go for it. Teams will still punt occasionally, but the question will become "why did you punt when you would normally go" instead of "why did you go..." If anybody looks back on yesterday, they'll wonder what all the hubbub was about. The forward pass was controversial once too. It would be amusing to hear anybody make the conventional wisdom argument of 60 years ago today.
One minor request:
Could you post a copy of a graph that showed the two lines above on the same graph along with the probability of scoring a TD or FG and a TD in non 2 minute circumstances?
I know that you have the regular graphs elsewhere on the site. Superimposing how much of a difference it is between 2 minutes and regular time would probably be helpful for others.
Although you had alluded to those scoring percentages in previous posts, seeing them graphed out is compelling. In the wake of the Great Belichick Blunder of 2009 (as the pundits would have us believe), this whole topic is receiving massive attention.
I would really like to say, as Jeff does above, that this will lead to more logical go-for-it decisions in the future. But the whole Belichick fiasco has really opened my eyes to the fact that the sports world is even more short-sighted and small-minded than I had previously believed. Yesterday I could not escape all of the "experts" who couldn't resist the opportunity to pile on Belichick for his putatively boneheaded decision.
With the cacophony of ignorance ringing throughout the sports world right now, I find it hard to believe that coaches will feel MORE compelled to make the smart play in the future. I can only imagine that they will think, consciously or subconsciously, that they don't want to be behind the same crosshairs currently focused on Belichick. I can only imagine that this will foster an even greater propensity to go for the "safe", conventional play.
I wonder if that lower red zone touchdown percentage is at least in part because it is possible to get to 4th down with 1:45 left and still have three time outs. I think there are plently of coaches that would make the irrational decision to kick a field goal thinking they could get the ball back to win the game.
What are the raw #s for those percentages? And what games were they?
What are the percentages when the game is tied? Also, how often does the other team get the ball in these situations and score to win the game?
Alchemist,
I actually feel pretty optimistic about the whole long term effects of this. The knowledge of the math has been seeping into the coaching pool and they are going more often. The knee jerk "omigod what was he thinking" story was printed a lot. On the other hand, the math on our side was printed a lot as well. I think that will force coaches to think about it in the future. Someday soon, somebody will lose by punting in that situation and a reporter will ask why they didn't go for it. You can only go so far by quoting "the numbers" without giving any actual numbers.
Its going to be a slow evolution, but they are definitely evolving. Think about how the league evolved from its never throw the ball unless you are absolutely desperate routes. Nobody just decided to line up in a 4 wide receiver West Coast front one day. This takes time.
It looks like roughly 50% chance of making a 26-30 yd TD and roughly 22% chance of making a 66-70 yd TD based on the graph.
So assuming 60% chance of converting a 4th and 2, the Belichek equation becomes:
.6 + (.4*.5) = 80% chance of winning.
Punting would result in a 78% chance of winning based on the chart.
Basically a wash.
The decision actually favors the punt if the conversion percentage is less than 60%. 2 pt conversions are essentially a 4th and 2, and they get converted somewhat less than 50% of the time.
If you use 50% as the conversion percentage, then the smart move becomes to punt the ball.
"It looks like roughly 50% chance of making a 26-30 yd TD and roughly 22% chance of making a 66-70 yd TD based on the graph."
It looks like you're using the blue line -- the black linear approximation is better and appears to be what Burke used in his analysis of the Pats/Colts game.
I'm surprised nobody has mentioned Super Bowl X yet.
From Wikipedia:
"After Gerry Mullins recovered Dallas' onside kick attempt, the Steelers then tried to run out the clock on the next drive with four straight running plays, but the Cowboys defense stopped them on fourth down at their 39-yard line, giving Dallas one more chance to win. Some questioned why Noll would elect to go for it on fourth down but, as later explained by NFL films, his entire kicking game had been suspect all game long with Gerela missing an extra point and two field goals while Walden fumbled a snap on a punt and nearly had two others blocked. (Gerela's problems may have begun on the opening kickoff when he was forced to make a touchdown saving tackle on Hollywood Henderson.)"
Not exactly the same reasoning, but certainly an unconventional decision in that situation.
Well yes the first thing I thought of was SB X as I was a young pittsburgh fan. I recalled the ball being more at midfield, and as it turned out Staubach wound up getting two passes into the endzone, the second one being picked off by Glen Edwards I think.
But the other game I thought of was the Green Bay Packers next to last regular season game of the 1967 season. They lost to the Rams, Lombardi opted to go for it in his own side of the field on fourth down late in the game. Previously the Rams had blocked a punt.
I think in both games, there was a punt blocked. As didnt Walden have the punt blocked in the early 1st quarter which led to the first score of the game?
I think the Packers were probably in the neighborhood of 30-40 yard line.
I cannot imagine either Noll or Lombardi going for it the Belicheck situation, if their punting game wasnt suspect.
A perfect game for comparison is the 2006 AFC Championship (a bit different but I haven't seen it mentioned much)
NE leads Indy by 3 with 2:20 to play, 4th & 4 at their own 46 and Indy with 1 timeout. Belichick elects to punt, which goes for a touchback.
Indy drives and scores a TD in 1:30 to win the game and go to the superbowl.
No one crucified belichick for not going for it there
I second Jeff's request. It has often seemed to me that teams are much more effective in situations in which they "need" to score than they are at other points in the game. I have witnessed plenty of games in which a team struggles to move the ball throughout the contest, but then marches down the field to score when the game or half is near the end. In these situations, I find myself saying, "Why didn't they play like this the whole game?"
It might be difficult to control for factors like the prevent defense or more aggressive offensive strategy, like going for it on 4th down, but I would be interested to see if teams are more or less likely to score because of the more aggressive play calling and any disruption in defensive preparation that comes with the 2-minute drill than they are running a conventional offense.
I'm sorry. I meant to respond to this yesterday. Here is the comparison you're looking for.
http://www.advancednflstats.com/2009/01/drive-results.html
The reason why people think teams do so much better in the last two minutes is the availability heuristic; i.e., people remember the exciting TD drives and forget the plain vanilla defensive stops.