89.5 The Club: Off/Def Rating Re-Intro


Over a year ago we came across this stat when we kept hearing on sports radio and twitter that teams had to be in the top 10 in offense and defense to win a championship. That sounded too broad and non-researched to be true so we decided to find out for ourselves. Rankings for Offense and Defense is a generic term and there are several stats that could be considered “Offense” or “Defense.”

Ranking by simple Points Allowed and Points Scored doesn’t give us a good measure of efficiency because it doesn’t account for pace of play. The famous “7 Seconds of Less” Suns in 2005 played up-tempo and fast, so they scored a lot of points very quickly. They did. That means they also had a ton of possessions on defense and had numerous opportunities to be scored on. They did.

You could measure and track Field Goal Percentage and Field Goal Percentage Allowed, but similar problems arise. Field Goal Percentage doesn’t account for free throws or for good defensive plays. If you get a steal on defense, go coast-to-coast and dunk it it only improves your offensive Field Goal Percentage, not your Field Goal Percentage Allowed because the opposing team never got a shot off.

So we started to dive into advanced stats and one that immediately jumped out was Offensive & Defensive Rating, or what we’re calling Off/Def Ratings. Off/Def Ratings track the number of points scored or allowed per 100 possessions.

Off Rating tracks the number of points scored per 100 possessions
Def Rating tracks the number of points allowed per 100 possessions.

For example the Clippers had the #1 Off Rating last season at 110.5 points per 100 possessions. The Warriors had the #1 Def Rating in the league at 97.3 points allowed per 100 possessions.

That seemed like a good measuring stick to try and calculate how efficient a team is on both offense and defense, but does the narrative stack up? Do only Top 10 ranked teams win championships? We recorded every champion’s regular season Off/Def Ratings over the last 19 years (The Off/Def Rating stats on NBA.com are limited to the last 19 seasons) and here they are:

Screen Shot 2015-10-24 at 3.28.48 PM

It seems to be all over the map but there are a few trends. The initial theory that teams needed to be Top 10 in both Off & Def Rating kind of broke down with the 2010 Lakers (11th Off), 1998 Bulls (12th Off), and the two eventual exceptions to the rule: the 2004 Pistons (20th Off) and 2001 Lakers (18th Def). We expanded the rule to include the Top 12 but it seemed excessive to expand to the 18th & 20th rankings for two more exceptions. Bringing the stat to the 89.5% advertised. Meaning… 

89.5% of the last nineteen NBA Champions were ranked in the top 12 in both Offensive and Defensive Ratings.

If you specify this statistic to the last 14 years that percentage rises to 100%. Every team that won the championship the last 14 years has ranked in the top 12 in both Offensive & Defensive Rating. Every single team. I’m repeating this statement for emphasis. EMPHASIS!

This year we’re going to track the rankings of the top 15 teams in Off/Def Rating to give us a better look at who is on pace to win the Championship. The teams that rank in the Top 12 in both Offensive & Defensive Rating will be awarded membership into 89.5 The Club. If you’ve followed me on this site, first of all thank you, second of all you may have seen something about the 86 Club. This is the same statistic only improved, expanded, and more precise. This stat will continue to be improved and change over time as more teams qualify for The Club, as the Warriors did last season.

So keep following here on [Open] Practice as we track 89.5 The Club to find out who can/could/will win the NBA Championship.

For reference, here are the top 15 Off/Def Ratings for the preseason. These are just the NBA teams, not the international teams that teams played in preseason games; however, it would be impossible to not include numbers from those games in  this chart. The highlighted teams are the ones that would qualify or are close to qualifying for 89.5 The Club. This means almost nothing as the 2014-15 Clippers had the 23rd ranked Offensive Rating during the preseason and ended with the #1 ranking.  This is just so you can see and understand how we’re going to present this information:

Screen Shot 2015-10-24 at 3.06.14 PM


6 responses to “89.5 The Club: Off/Def Rating Re-Intro

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