Many pundits believe that Belichick’s decision to go for it on 4th and 2 meant he had no confidence in his defense. As we will see, it is much more likely that the decision was driven by confidence in his offense rather than doubts about the Pats defense.
Recall from our last post that the Pats should have gone for it if
MAKE + (LONG/SHORT)>1.
Here MAKE = Chance of getting a first down for PATS
LONG = CHance Colts score TD sfter punt.
SHORT C= CHance Colts score after failed attempt at first down.
The key insight is that LONG/SHORT probably does not depend much on the quality of the PAT’s defense. For example, if the PATS defense were good we might have LONG =.3 and SHORT =.6 and if the PATS defense were bad we might have LONG = .45 and SHORT =.9. In either case LONG/SHORT would equal .5.
On the other hand, the better the Pats offense, the higher MAKE would be, and a higher MAKE would make it more likely that the rational move is to go for it.
I think this logic shows it is much more likely that confidence in Tom Brady rather than defensive doubts drove Belichick’s decision to go for it.