It’s been two days and the shock waves from James Harrison’s unbelievable 100-yard interception return for a touchdown are still reverberating. Commentators usually refer to that kind of play as a “pick-six” because of the six instant points for the defense’s cause. But Harrison’s play was no pick-six. It was more of a pick-thirteen.
Having possession of the ball at various field positions is worth a certain average number of points. For example, having the ball with a first down on the 50-yard line is worth an average of +2 expected points for the offense. This means that, on balance, the next score is going to be by the team on offense, and the net of all the “next scores” favors them by 2 points.
The average field position in the NFL is actually midfield. So when a QB throws a pick-six, he’s giving up more than 7 points to his opponents. He’s also forfeiting the +2 point advantage he had. On average, an interception return for a touchdown is about a 9-point swing.
Harrison’s return in the Super Bowl however, came on a first down and goal from the 1. There, the expected points for the Cardinals offense was +6.1 points. The return was effectively a swing of 7 points for the touchdown, plus 6 expected points denied to the Cardinals. It was the Super Bowl’s first pick-thirteen.
Further, the value of the touchdown was even higher than most scores. Because time expired during the play, the Steelers did not need to kick off to the Cardinals, giving them possession and an opportunity to answer and score themselves. Normally, receiving a kickoff is worth +0.6 points, the value of having the ball at your own 27 with time enough to mount a drive. So the value of the play could be considered even higher.
A Pick-Six?
published on 2/03/2009
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However, the value of the Cardinals' possession at the Steelers' 1 before the interception was almost certainly lower than the average possession at the 1. They were out of timeouts and almost out of time, so they effectively couldn't run the ball and had limited downs available to score.
Doesn't Brian's system account for time remaining?
Possibly. Every situation is unique. But they had 18 seconds, time for 3 3-step drop pass attempts then a FG kick if necessary. They weren't going to run on the Steeler goal line run defense anyway.
bmoore-The WP system does that. My post above is about expected points.
You're correct Brian. The Cardinals would not run the ball in that situation since it would limit the amount of plays run. Any pass attempt would have been incomplete or touchdown thus stopping the clock and giving the Cardinals four downs to put points on the board.
KA
Although it's most unlikely that the Cardinals would have run on this play I am perhaps the one strategist who would have called for a run. Assuming my offense was prepared for a run and if unsuccessful a no-huddle spike would still leave enough time for a FG try. The element of surprise is not easy to measure but worth the gamble.
Ed
Now that I think about it some more, the fact that there was very little time on the clock may in fact reduce the expected points for the Cardinals on the 1...but not because they had to hurry and only pass.
It's because the expected points at the 1 takes into account the possibility that had Arizona been stopped at the goal line, they would have probably got the ball back in favorable field position had enough time been left in the half.
Because that possibility doesn't exist, the actual expected points would be slightly lower. On the other hand, had they scored, Pittsburgh would not have any time to score themselves. So on balance, I'd bet the 2 effects approximately cancel out, and the +6 expected points is about right. But I'd have to do a full analysis to be sure.
Well if you look at it from the other side, 6 points look awfully low.
3rd and 1 is successful something like 50% from the pass and 70% from the run if I remember correctly.
Even if you say due to the special situation its only half that you get expected points of 5.4 without accounting for TO.
Since this are rare and even rarer returned for a TD I would guess they don't really affect the average. So 5.5 is a low estimate for a high scoring Offense with a mythical halfgod at WR1.