Part of the reason is a ceiling effect. Even though the Patriots are almost always good, they cannot win more than 16 games in a season, making it tough to set an over/under at 14 or 15. But most of the reason is the expectation that great teams, even the Patriots, tend to slide downward.

In contrast, the nine worst teams last season are all expected to be better. Again, the biggest improvements are expected from the worst teams, led by the Browns, who were 1-15, but are expected to win about four and a half next season.

All of these teams will not follow the pattern. But in aggregate, they are virtually certain to.

In 2015, there were seven 11-win teams. Only two of them won more games the next season, the Patriots and the Chiefs. Three of them had losing records.

Of the 11 teams with six wins or fewer, only four — the Bears, the Niners, the Jaguars and the Browns — got even worse. The others all improved, and three of them won 10 games or more: the Dolphins, the Giants and the Cowboys.