The Relativity Index

Through Week 12 of the 2012 Regular Season

About the Relativity Index. The Relativity Index measures the performance of each team relative to the performance of its opponents in all other games. Essentially, it adjusts for the quality of competition each team faces, and spits out a number that tells us how greatly a team overachieved, or how badly a team underachieved, relative to the quality of competition. You should pay attention to the Relativity Index because it's the indicator we use to adjust for the quality of each team's competition.

For example, if Team A scores 25.0 PPG, and its opponents surrender 20 PPG in all of their other contests, Team A is +5.0 PPG on offense. If Team A surrenders 20 PPG, and its opponents score 25 PPG in all of their other contests, Team A is +5.0 on defense. This equates to a total Relativity Index score of +10.0 PPG. In other words, Team A is 10 points better than the average performance of its opponents.

PS = points scored, on average, by that team; OPA = opponents' points allowed, on average, in all other games; PS-OPA = the difference in those two numbers; PA = points allowed, on average, by that team; OPS = opponents' points scored, on average, in all other games; OPS-PA = the difference in those two numbers; REL = Relativity, the sum of PS-OPA + OPS-PA, giving us the margin by which a team outscores, or is outscored by, its opponents compared to their performances in all other games.