This article is part of our Numbers Game series.
Defensive rating is an easy catchall for the overall quality of a team's defense. It is a measure of how many points an opposing team averages per possession. It tracks the direct objective of a defense – to stop the other team from scoring. Since scoring is such a major part of the fantasy game, defensive rating is one of the advanced stats most used by analysts and managers alike.
When analyzing the importance of pace for last week's column, I found that the results were most reliable if a team's defense – according to defensive rating – was average. This led me to consider, are the same teams average all the time? Can I check once now, and then just remember who the best and worst are? Do team defenses perform consistently over the course of the season?
How Did You Figure That Out?
I started by breaking down the 2015-16 season into the five months completely contained within the NBA season – November, December, January, February and March. This allowed me to ignore the first couple games of the season, allowing teams to settle into some sort of rhythm, as well as the late season games that can be heavily impacted tanking teams and players resting for the playoffs.
Next, I normalized the data – we are interested in how good teams are compared to one another, not compared to some arbitrary numeric benchmark. The normalized data showed how a team compared to the rest of the