What SoS, OSRS, DSRS and SRS mean
These four numbers appear on every team card and game. All of them are in points per game compared with an average NFL team, so 0 is average, positive is better than average and negative is worse.
SRSSimple Rating System
The team's overall strength. It is based on points scored and allowed, adjusted for how good every opponent was. An SRS of +7 means the team is about 7 points better than an average NFL team on a neutral field.
SRS = OSRS + DSRS
OSRSOffensive SRS
The offense's share of SRS. It measures how many more points per game the team scores than an average team would, after accounting for the defenses it has faced. Higher means a better offense.
DSRSDefensive SRS
The defense's share of SRS. It measures how many fewer points per game the team allows than an average team would, after accounting for the offenses it has faced. The sign is flipped so that higher is better: +7 means the defense gives up about 7 fewer points than average.
SoSStrength of Schedule
The average SRS of the opponents the team has played so far. Positive means a tougher-than-average schedule, negative means an easier one. It describes games already played, not the rest of the season.
Example: this week's top-rated team
Using them in a matchup
- Rough point spread: subtract one team's SRS from the other's. A +6 team against a +1 team projects as about a 5-point favorite on a neutral field. Add a point or two for the home team, since the ratings themselves don't include home field.
- Where the edge is: compare one team's OSRS with the other team's DSRS. A strong offense facing a weak defense is where points are likely to come from.
- Grain of salt: check SoS. A big SRS built on an easy schedule rests on less evidence than the same SRS against strong opponents.
Where these numbers come from
- All four come from Pro-Football-Reference's standings for the current season and are refreshed with every weekly update. Only regular-season games count.
- SRS is the team's average margin of victory plus its strength of schedule, solved for all 32 teams at once so that every team's rating reflects every opponent's.
- OSRS and DSRS split the same calculation into points scored and points allowed, so OSRS + DSRS = SRS (give or take rounding).
- Margins are not capped, and there is no home-field adjustment.
- Ratings are recalculated every week, so a team's SoS and SRS can change even in a week it doesn't play, as its past opponents' results come in.
Early in the season, with only a few games per team, treat all four numbers as rough. They become more reliable as more games are played.