By Daniel Adler
Here at the Sports Analysis Collective, we often do some pretty complex analysis. However, this post is about something at which this guy excels. One thing that has always interested me is a coach’s decision of when to go for two. Historically, two-point conversions are successful 44% of the time and the one-point attempt rate is successful 99% of the time. Thus, the expected value of a kick is .99 points (99% x 1 point) and the expected value of going for two is .88 points (44% x 2 points). Obviously, there are still situations in which going for two is the right move. Since all that adding by 1, 2, 3, 6, 7, and 8 can be confusing in the heat of the moment, coaches often use a chart, which tells them what to do. Here is a common one. We’ll analyze Tony Sparano’s (seemingly) ridiculous decision after the jump.
With the team up by 11 and just under 9 minutes to play, Sparano went for 2. What is the advantage of being up 13 vs. 12? Blocked extra points aside, there’s not a huge difference if the other team scores 2 TDs. Let’s look at other possibilities…Yes, 12 points loses if you allow a touchdown and two field goals, but with 9 minutes remaining, that seems far-fetched. It seems to me the greater concern should be the TD+2pt and FG combination. However, with 9 minutes to play, three drives is possible. Also, perhaps the odds of TD, FG, FG are greater than TD+2pt, FG. Still, it seems like a bad move. Why not make it a 2 TD game rather than a possible TD+FG game?
Still, Sparano’s decision is supported by this chart (but not this chart). However, analyzing a more nuanced chart created using win probability, we see that Sparano made the wrong decision (unless he felt his team had a >80% chance of converting the two-pointer). However, the chart does reveal a little more. When up by 11, it is never a good idea to go for two (assuming 44% conversion rate), but it is a less bad idea with more time remaining. Sparano’s explanation that he did not know how many more “at-bats” the Jets were going to get is actually sensible (however, he does not say he thought that number would be high…if he thought it would be low, his decision was really bad). If he thought the Jets were going to get a lot of “at-bats,” then going for two was not the worst idea in the world. Still, the Jets had only 2 timeouts remaining, which made it less likely they would get lots more chances to score.
In the end, the Dolphins won and Sparano was spared horrible embarrassment. Still, it is interesting to analyze his explanation. To me, it sounds like the “at-bat” comment was just a cover-up, but when we look at the numbers, if you give Sparano the benefit of the doubt, he may just be onto something. In the end, no matter how you cut it, it was the wrong move. Not surprising from a guy who used to be the head coach in New Haven…no, not that New Haven, but this one.