Dre at Wages of Wins has a post up discussing the 4th down choices from the game last night, noting that out of 9 tries two of the best teams in the league made the wrong choice three times. I put in my two cents in the comments; using Brian Burke’s analysis, I think you could argue that they made the wrong choice maybe 1.5 times. And of course, those decisions are based on point maximizing, which may not always be the end goal; for example, when the Packers punted on 4th and 4 from the Saints’ 37 it might have led to a decline in their expected points, but it may have been the right call for ensuring victory since there was only a minute left and they were up by 8. A quick look at Brian’s WP calculator says that with the punt going in the end zone the Packers were 95% to win (had they successfully covered it at the 1 it would be even higher); had they gotten the 4 yards they would have gone to 99% (really 100 since they could have kneeled out to finish the game); and had they gone for it and gained 0 yards they would have been at 92%. So the Packers were very likely to win regardless and could worry more about playing it safe than scoring more points.
But what Dre’s post really made me realize was that with the new kickoff rules, teams will be starting from the 20 more often. The current 4th down analyses all include a subtraction for the other team’s field position after a score, assuming that they’ll start at the league-average position of the 27. But with teams starting from the 20 more often, the average starting position should move closer to their own end zone, which is a less advantageous position. That means that touchdowns and field goals become worth more expected points, meaning teams should go for it even more often on 4th down. To what extent isn’t clear; it’ll depend on what the average starting point ends up looking like, and it only makes a difference of a few tenths of an expected point. But every time you read an article this year about how teams should go for it more often and you see numbers to back it up, the situation is probably even a little worse than what the writer said thanks to the new rules.