November 19, 2009

Did Belichick diss his Defense?

Filed under: Uncategorized — wwinston @ 7:42 am

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


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.


  1. Or another way to look at it is that it deosn’t much depend on the oppostion’s QB skill level – pretty much the same threshold whether Peyton Manning or an average QB is playing.

    Comment by steve — November 19, 2009 @ 1:52 pm

  2. Excellent point. We’ll discuss it over drinks in my office.

    Comment by Don Draper — November 19, 2009 @ 1:54 pm

  3. i want to know 3 things

    Originally i felt that bb should go for it if he had time outs.I felt that otherwise no he should punt.So i want to know if time outs change your probability.
    Also-Tony Dungy stated that most 4th and twos have been defensed with prevent defenses,I also happen to believe his thinking there.The colts were do or die and they knew it was going to be a pass.
    Lastly,the patriots basically called the same play on 3rd and 4th downs.I happen to believe this- that if a certain play is called on 3rd down and fails then if a similar play is called on 4th down that the result will be similar.

    Comment by cre8flow — November 24, 2009 @ 9:53 am

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