A few years ago, I noticed that one of the prevalent beliefs in the NFL is a myth: it is widely thought that it doesn't matter whether an NFL team bound for the playoffs wins its last regular-season game. Accordingly, many playoff teams rest some of their starters for their final regular season game, as the Chicago Bears did last year in their season-ending loss to Green Bay, a precursor of their loss in the 2007 Super Bowl. Like NFL coaches, many commentators also do not seem to understand that losing the last regular-season game is an excellent indicator of not making or not winning the Super Bowl.
Since the 1995-96 season, only one of the 12 Super Bowl winners (the 1999-2000 St. Louis Rams) lost their last regular-season game. Further, one would have to go back to the 1980s before finding a Super Bowl winner who lost its last regular season game by more than 7 points.
Why is this so? Of course, some strong teams need to win their last game to maximize home-field advantage in the playoffs, but other strong teams may simply be good enough to win even when they are not trying their hardest.
Whatever the reasons, winning your last regular-season game is an important indicator of your ability to win the ultimate prize: the Super Bowl.
Note that this analysis does not necessarily mean that resting your starters in the last game is the wrong strategy: perhaps you had almost no chance to win the Super Bowl anyway so resting them made no difference, or perhaps you are good enough to win the last game without your starters, in which case resting them might be the right move. But whatever the pre-game probabilities might be, after the game your chances of winning the Super Bowl are slim if you lost the final regular-season game (and especially if you lost by more than 7 points).