I was at the game on Saturday with one of my friends from college, who is a pretty sharp guy. As Michigan scored their second TD in overtime, he made a case for going for two right there instead of kicking an extra point and forcing a third period.
His reasoning was that both offenses were likely to score on the next possession so we should try the 2pt conversion now, when Illinois would not have a chance to answer. At the time this line of reasoning sounded okay; however, I decided that it was somewhat unconvincing. The fact is that as long as our win percentage is higher by kicking an extra point than by going for two, we should, quite obviously, kick the extra point.
The question then becomes, is it possible that our chances of converting the 2pt conversion are higher than our chances of winning in a third overtime? In order to determine the answer to this question, I had to consider a few different factors:
1. We were going to be playing offense first, which carries with it a strategic disadvantage. What is the inherent disadvantage that we’d have in the next overtime?
2. What are the chances of our team converting a 2pt conversion? How much more likely are we to convert than an “average” team?
3. How likely is it that the kick to force a third overtime will be successful?
I did a bit of research and found a study that showed that the team that starts on defense wins about 52.25% of the time in the third overtime and later. You can find the study here. And, looking at M’s kicking statistics I’ve found that the team is 46/47 on extra point attempts, 98%. I used that for our success rate in this spot. So when we kick the extra point we’ll win .4775*.98= .468. So if we can convert the 2pt conversion 47% of the time, we should go for 2.
How often should we expect to make a two point conversion? Advanced NFL Stats says that the conversion is good, on average, 44% of the time. So obviously, if we had an average chance of converting, we should kick the extra point. But our offense is significantly above average.
In order to decide how much more often our 2pt conversion would be successful than an average team’s conversion, I divided our total offense in terms of yards/game by the national average. The result is a multiplier which I applied to the average 2 pt conversion percentage. Our total offense per game is 536 and the national average is 384 giving us a multiplier of 1.39 (our multiplier is similar when considering scoring offense). Applied to the average conversion rate of 44%, our new conversion rate should be 61%.
Now this seems pretty high to me, but given the things we’ve seen our offense do this year, I’d be surprised if we didn’t fall somewhere above the 47% necessary to make going for two at the end of overtime correct.