With seven weeks of the N.F.L. season in the books, there are still five undefeated teams. In sorting them out, we can turn to a simple but accurate measurement of a team’s strength: point differential. Teams that win games by large margins are, of course, generally better than those who are winning mostly close games.
By this measure, the defending champion Patriots rank first among the unbeatens, at plus-87, aided by a 51-17 shellacking of the Jaguars in Week 3. Close behind are the Packers at plus-63 and the Bengals at plus-60.
Lagging are two unbeaten teams that show some clear flaws, especially on offense, the Panthers at plus-52 and the Broncos, who have won their six games by margins of 6, 7, 12, 3, 6 and 3 points, for a plus-37 that looks like it should belong to a 4-2 team.
But to find the top team in football by this metric, we must look…