Welcome to By The Numbers, a rating system for college football teams. The ratings come from a computer, but that does not make them correct. However, I can tell you exactly what determines the ratings, so you can make whatever corrections you think are needed. There are three factors that determine the ratings: (1) schedule, (2) wins minus losses, (3) points for minus points against. No adjustments are made for home field, style of play, when a team lost or to whom it lost. A brief description follows.

In its basic form, the ratings are determined in the following way. If team A is averaging 5 points per game more than its opponents, its rating will be 5 points higher than the average of its opponents' ratings. Of course, this creates a vicious circle: to find team A's ratings, you need to know its opponents' ratings, but to know the opponents' ratings you need team A's rating. The computer is used to sort out all of the schedules and results. Wins and losses are factored in by doing a separate rating where each win is counted as a 20-point victory. The two ratings are then combined.

In the past, the ratings have done well at predicting games, averaging about 60% against the point spread through most of the 1990's and 52% more recently (Vegas has gone digital, as well). Most of the differences in these ratings against the polls can be attributed to strength of schedule being an important factor. This is also a characteristic of the computer ratings systems used by the BCS.