Bill Belichick + Statistics = Usually Good Outcomes
I’ve been a die hard Giants fan for as long as I can remember, and although I was technically alive and barely remember parts of the 86 season (and nothing from that Super Bowl), the 90 Super Bowl team made me love the G-Men . They had me at Mark Ingram’s 3rd and 13 conversion.
Bill Belichick was the Giants’ defensive coordinator in that Super Bowl and designed a genius defensive game plan, predicated on the statistics of his defensive unit. Knowing that Jim Kelly and the Buffalo Bills could rip apart the Giants’ secondary, he had his defensive linemen and linebackers give up yards on 1st and 2nd down. He believed that this would dictate that Buffalo would run the ball, rather than pass in longer 3rd down situations, a place where the Giants were statistically strong in all season.
His gutsy calls are not relegated to just defense. The 07 Patriots’ offense was a great example of not playing into defenses strengths (case in point, going to five WR sets against the top ranked Minnesota run defense), and taking gratuitous unsportsmanlike advantages of your strengths when the game was well out of hand. Gratefully honor prevailed and the Giants laid the smack-down on the Patriots to win their 3rd Super Bowl and squash a rather presumptuous book before it made its way onto bookshelves.
Last night’s Patriots Colts game is just another way Bill Belichick makes football analysts (like Mike Francesca) and arm-chair quarterbacks look like idiots. It was absolutely the right move to go for it on 4th and 2 and the odds were completely in his favor, as described on “Advanced NFL Stats:”
“With 2:00 left and the Colts with only one timeout, a successful conversion wins the game for all practical purposes. A 4th and 2 conversion would be successful 60% of the time. Historically, in a situation with 2:00 left and needing a TD to either win or tie, teams get the TD 53% of the time from that field position. The total WP for the 4th down conversion attempt would therefore be:
(0.60 * 1) + (0.40 * (1-0.53)) = 0.79 WP
A punt from the 28 typically nets 38 yards, starting the Colts at their own 34. Teams historically get the TD 30% of the time in that situation. So the punt gives the Pats about a 0.70 WP.
Statistically, the better decision would be to go for it, and by a good amount.”
It didn’t work out for Bill last night, but the decision was sound, and in the long run, he’s going to come out on top more often than not. It’s why he’s a great NFL coach, and we shouldn’t be convinced that our “conventional” wisdom is better than his statistical prowess. Just be content knowing that he’s a prick and move on.
Love the post. You nailed it.
For completeness, I offer the general solution: One goes for it if the following relationship holds:
Off_4th_down >= (D_far – D_near) / (1 – D_near)
Where:
Off_4th_down = offense’s prob of making 4th down
D_near = defense’s prob of stopping the opposing team if offense fails on 4th down
D_far = defense’s prob of stopping the opposing team if offense punts
There’s a cleaner way to write that equation if you redefine the variables a little, I just realized:
Off_4th_down >= 1 – Opp_far / Opp_near
Off_4th_down = prob your offense makes 4th down
Opp_near = prob that opponent will score if you fail on 4th down
Off_far = prob that opponent will score if you punt
Assign your own probabilities to those variables and see if you agree with Belichick.