# SRS ratings

The Simple Rating System (SRS) measures team strength from scoring margin after
adjusting for schedule strength and home field. It evaluates the network of
game results together so that performance against a strong opponent is not
treated the same as an identical margin against a weak opponent.

Higher values indicate stronger performance. A rating of `8.0` can be read as
roughly eight points better than the average FBS team on a neutral field within
that season's rating system.

## How it works

SRS starts with adjusted scoring margins from completed FBS and FCS games. It
then solves for the set of team ratings that best reconciles each team's
results with the strength of its opponents. Extreme scoring margins are
limited so that one unusual game does not dominate the season estimate, and
the final FBS ratings are centered around zero.

This is a season-to-date descriptive rating. It is not a win probability and
does not separately rate offense, defense, or special teams.

CFBD SRS is proprietary. Exact margin limits, home-field values, and full
calculation details are not published.

## Standard and expanded SRS

The standard endpoint returns FBS team ratings. The expanded endpoint includes
additional classifications where ratings are available, which can be useful
for analyses involving FCS opponents.

`rating` contains the point-based SRS value. `ranking` is the team's ordered
position when teams are sorted from highest to lowest rating; it is not an
additional model output.

## Limits to keep in mind

Early-season SRS can be unstable because the schedule network contains fewer
games and less cross-team information. Ratings become more connected as the
season progresses, but they still summarize the games played rather than
projecting a specific future matchup.

Comparisons are most meaningful within the same season and endpoint scope.

## API access

- [FBS SRS ratings](/api/ratings#getsrs)
- [Expanded SRS ratings](/api/ratings#getexpandedsrs)