When looking at a box score, some of the first stats a coach will check are the rebounding totals. Rebounds are obviously an extremely important aspect of the game, but the totals alone don't tell the whole story.
How is the offensive rebounding rate/percentage calculated?
Offensive Rebounding Rate/Percentage = (Offensive Rebounds)/(Offensive Rebounds + Opponent’s Defensive Rebounds)
Rebounding percentages and specifically, for Four Factors purposes, offensive rebounding rate (ORR%) tells a much clearer story of the battle on the boards. The reason being that rebounding totals do not take into account the number of missed shots. Collecting a larger percentage of your missed shots or preventing the opposing team from doing so is more important than the raw number.
For example, in the second game of the Raptors-76ers series in the 2019 NBA Playoffs, each team finished the game with nine offensive rebounds. A cursory glance would tell the casual observer that neither team had much of an advantage on the offensive glass. However, this is very much not the case.
When we look at the offensive rebounding percentage, the rebounding advantage of the 76ers becomes apparent. Of Philadelphia's 36 offensive rebound opportunities (PHI Off Rebs 9 + TOR Def Rebs 27), Philly pulled down nine of them or 25%. On the other hand, Toronto had 53 offensive rebound chances (9 + 44) and managed only 17%. In other words, not only did Toronto miss more shots than Philly they also missed more chances for 2nd chance points.
~25% = (9)/(9 + 27) - PHI
~17% = (9)/(9 + 44) - TOR
How can you use ORR to evaluate athletes?
As with the other Four Factors, it is important that ORR always be applied to a team and their opponent. In the above example, Philly's ORR of 25% is fairly meaningless until it is compared to Toronto's 17%. This is true from a season long perspective as well. Essentially, the Four Factors are really eight, as you should always look at the metrics of a team as well as their opponent, either in a single game or in the aggregate over multiple games.
Additionally, ORR can be applied at the player level as well. This can either be a On Court Team ORR or that players actual rebounding production. Both of these numbers can be valuable. For example, a player that boxes out extremely well may not have the highest individual rebounding numbers, but the team rebounding impact will be more visible.
At Pivot, we are incorporating the ORR as well as several other tried-and-true basketball metrics, such as offensive and defensive rating, into each of our applications.