Monday, September 08, 2008

A nine-yard gain is better than a first down

What's better on first-and-10: gaining 10 yards for a first down, or gaining 9 yards for second-and-1?

Brian Burke shows us that the nine-yard gain is better. That's because, effectively, it gives the offensive team a free second-down pass. If they fail to connect, they just run on third-and-1, which has a very good chance of succeeding (and so does fourth-and-1, if they fail to make it on third down).

Brian studied all first-down plays between 2000 and 2007 outside of field-goal range in the first 28 minutes of the game. From that database, he was able to figure that the difference is quite large: almost a whole point on the scoreboard.

So should teams deliberately choose to gain nine yards instead of 10? Yes, in theory. In practice, of course, it doesn’t make sense to deliberately go down at 9, because you don't know for sure that you'll be stopped at 10 – you could wind up at 16 or 17. Also, as Brian points out, coaches are risk-adverse:

" ... the first time anyone actually did it intentionally, and his team failed to convert the 1st down, the criticism would be merciless and it would never be done again."

However: what's to stop teams from doing it "kind of" deliberately and hoping nobody notices? Nothing. And the evidence does suggest that it does happen. Although gains of more yards are generally less frequent than gains of fewer yards, the drop from 9 yards to 10 is particularly steep. Furthermore, 10-yard gains are actually less frequent than 11- and 12-yard gains.

Of course, that might not have anything to do with offensive strategy. As Brian says, it could have to do with the way the referee spots the ball. Or it could be that defenses are guarding the first-down marker so well that the offense is brought down at nine yards.

So we don't know whether the offense is being smart, or the defense is unwittingly playing into the offense's (perhaps also unwitting) hands.

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At Tuesday, September 09, 2008 11:48:00 AM, Anonymous Anonymous said...

Thanks for the post, Phil.

Maybe it has nothing to do with strategy at all.

I would suspect that any specific advance, 9-yard or otherwise, is like lightning striking. Of course, some plays are adjustable so that a receiver runs their pattern at exactly the needed yardage for a first down, but that is different than the random occurrence of a 9-yard play.

Then the observation on the freebie 2nd down is just opportunism. Bart Starr was the first I ever saw quoted who said that 2nd and short is a freebie for (in those days) the bomb.

But then defenses also know that!

So it still ends up to be interesting that such opportunism (if that is the altnerative) really does seem to pay off.

Nice post.

At Tuesday, September 09, 2008 5:07:00 PM, Blogger Ted said...

Is the relative lack of 10-yard gains a rules artifact? Thinking out loud here; there's a distinction between the actual physical distance a play gains, and the accounting distance, which is always in whole yards. I assume that more plays are run with 10 yards to go than any other distance. Any first-and-10 play that goes between 9 and 10 physical yards is scored as a 9-yard gain. But, depending on where the ball is physically spotted relative to hashmarks, some just-less-than-9 physical yard gains will also be accounted as 9s. The same rounding will happen on the other side of 10. It wouldn't be a huge effect, but could be enough to change the ranking.

On the other hand, since the advent of the electronic first-down marker, one gets the impression, which I always thought was a mental illusion, that players play as if the line is painted there, even though it's not. Yet, at the same time, coaches preach being aware of where you are on the field to players all the time, so it's quite possible that good players do know where they are relative to the first-down marker.

At Tuesday, September 09, 2008 5:13:00 PM, Blogger Phil Birnbaum said...

Ah, so what you're saying is that an 8.9 yard game gets called 9 yards. But a 9.9 yard gain also has to also be called 9 yards, because if they call it 10, it's a first down.

Yeah, I bet you're right. That sounds a lot more plausible than the other two theories.

At Wednesday, September 10, 2008 5:12:00 AM, Blogger Brian Burke said...

Ted-I think you're right about the 10 yd gain. Gains in football are weird things. I think the basic rule is "how many yard line markers did the ball cross?" If the ball starts just behind a yd line, and moves an inch, it's a 1-yd gain. And if it is just ahead of a yd line and moves 1.9 yds, it's also a 1-yd gain.

An exception would have to be at 10 yards because you could conceivably have a situation where the ball crosses 10 yd line markers, but doesn't quite pass the first down marker. On tv, they'd call the next play 2nd and inches, but the NFL doesn't have "and inches" as an official 'to go' distance, just whole numbers.


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