A measurement of the difficulty of a team's schedule that is based on the win-loss records of their opponents. Teams that play a large number of teams that have recorded a large number of wins would be considered to have a good strength of schedule. When teams have the same record at the end of the season, strength of schedule is often used as a tiebreaker to determine playoff positioning.
Because teams do not play identical schedules, strength of schedule helps to differentiate between teams with identical records. If two teams end the season tied and did not play each other, strength of schedule often will be used to determine who had the better season. The team that played a tougher slate of games will win the tiebreaker. This can help decide who makes the playoffs, which team gets home-field advantage, and the draft position for the following year.
The win-loss percentage of all of the team's games is calculated by taking the record of each team and adding them all together, creating a final rating.