In football, "SOS" stands for "Strength of Schedule" and refers to the difficulty level of a team's opponent slate throughout a season. It's a statistical measure used to evaluate how challenging a team's path is compared to others, calculated by averaging the winning percentages or rankings of all the teams they will face.
The strength of schedule is particularly important in college football, where teams don't play the same opponents. A team with a high SOS has faced or will face stronger opponents, which can affect playoff rankings, bowl selections, and perception of their record. For example, a 10-2 record against difficult opponents is often viewed more favorably than the same record against weaker teams. The metric becomes especially relevant when comparing teams with similar records competing for limited postseason spots.
Strength of schedule can be calculated in different ways: some methods look at the average ranking of opponents, others examine win-loss records, and advanced metrics may weight recency or opponent strength more heavily. It's used by selection committees, sports analysts, and fans to contextualize team performance. The term is sometimes applied to the NFL as well, though the league's balanced scheduling format makes SOS less variable between teams. Coaches and analysts reference SOS when making arguments about a team's legitimacy or comparing achievements across different conferences and seasons.