noticed the WP graph for the recent Monday night meltdown had the Seahawk's chances at 0.01 prior to the game-ending play and thought it must be too low. He's correct.
There's a distinction between the WP model’s empirical methodology and its automatic output without any intervention or input from a human. When I do a detailed analysis for any specific play, I have the luxury of time and logic to dig directly into the data. The “auto” model that spits out WP estimates without any human input is based on lots of assumptions and interpolation on top of extrapolation etc. There are literally billions of combinations of game states (yd lines, downs, to go distances, seconds remaining, score difference, time outs). It’s just a matter of how much time I can put into coding the calculator to handle special cases like “a team's very last desperation play.”
With all the attention on that final play in the GB-SEA game, I thought it would be useful to look at Hail Mary success rates.
I looked at all the situations in which there were 8 or fewer seconds remaining (enough for one play) and a team needed a TD to tie or win (down by 4 through 8 points), and see how often they got that TD based on field position. This includes any plays that ultimately result in a TD, which would include any defensive penalty that enabled a subsequent scoring play. Even though SEA was specifically down by 5, the situations for being down by 4-8 are effectively indistinguishable for the purpose of estimating the chance they can get the TD.
From the 2000 through 2011 seasons, there were 223 examples in total--a little over 20 per 10-yard bin of field position. The chart below plots the TD success rate in the sample.
The Seahawks were at the 24 yd line, which would correspond to just over a 10% chance of a TD and winning the game.
-The one indicated TD from the offense’s own 24 was from a 2003 NO-JAX game. I'm told that's an error. Thanks for the correction.
-It’s possible in short ranges (inside the 20), teams could get off 2 plays, not just 1 with 8 sec left. Limiting the results successively to cases within 7, 6, 5 sec, etc. doesn’t affect the results around the 20-30 bin. Actually, only the 1-10 yd line bin drops, and it becomes measurably lower than the 10-20 yd bin. This might suggest that it’s easier to score from slighter further back from the goal line. (There’s more space for receiver routes.)