The problem with offensive rebounding stats is that the sample size is always so small. I mean, the difference between the top and the bottom team in offensive rebounding (Chicago and us, respectively), is 6. The difference between 1st and 20th is 3.
There are just so few offensive rebound opportunities in any basketball game, that a difference of one or two boards makes a huge impact on the percentage/efficiency numbers, that may be out of proportion to its actual impact on the game.
The way you have to look at it is each offensive rebound is basically an extra possession, and teams average close to a point per possession. The Knicks are 22nd in offense, another three offensive rebounds and they might be 8th or so in offense.
No, an ORB is not an 'extra possession'. It is simply a continuation of the current possession.
This gets to the fundamental game-value difference between offensive rebounds and defensive rebounds. A DRB is 100% the stoppage of a current possession with zero points. An ORB is just a continued _chance_ to score on the current possession.
Offensive rebounds are great when you get them. But their importance to winning the game is overrated by many fans. The main stat that ORBs correlates with is missed shots.
Every year, if you look at the rankings for which teams grab a lot of ORBs versus those who don't it is almost a reverse of winning percentage. Yes there are exceptions. Some years you do have an a few good teams (like this year's Bulls) that happen to also grab a lot of ORBs. But more often than not, the majority of top-10 ORB% teams have mediocre-to-poor records. Conversely, the majority of the bottom-10 ORB% teams each year tend to have winning records.
Doc's strategy is not too different than what most winning Celtic teams have used in the past:
1) Shoot for a high FG%.
2) Hold your opponent to a low FG%.
3) Rebound on defense.
If you can shoot above ~47% and hold your opponent to below ~43%, and you grab _defensive_ rebounds at above 70%, then you are almost always better off getting back on defense the moment you take your shot, rather than trying to crash the boards on offense.
The best teams at grabbing offensive rebounds only grab them about 30% of the time. And that is the _best_ at it. Most of the time teams only get the ORB about 25% of the time. Crashing the boards also puts you behind on defense, potentially exposing yourself to easy fast-break points.
If you instead get back on transition D, prevent easy layups and hold your opponent to a low FG%, making them miss at least ~57% of their first shots, and grab the defensive board at least 70%, then your chance of getting the ball back before they score is better than ~40%.
Note - the real numbers are more in favor of that than the conservative ones I am using here.
So, from the moment the ball leaves your hand on the shot, you have a much higher chance of getting the ball back before they score if you get back on transition D instead of 'crashing the boards'.
Obviously, if a rebound is there to be grabbed, you should go for it. This math is all about the general strategy, not saying you shouldn't try to grab offensive rebounds when they are there to be grabbed.
And obviously, if you are behind in the closing seconds and need to score on a possession quickly, you need to crash the boards because there may not be enough clock to execute the above strategy.
But the vast majority of the time, transition D should be a much higher priority than crashing the offensive boards.