I’m really obsessed with the distinction between “contested” and “free” rebounds. I’m curious to know how many rebounds in any given game can be classified as “gimmes” and which players tend to get the most “gimmes”.
So on Saturday during the second half of the Bucks-Bulls game I recorded, as best I could, the number of “contested” versus the number of “free” rebounds. I actually split the categories into 4: “contested” offensive boards, “contested” defensive boards, “free” offensive boards, and “free” defensive boards.
BUCKS vs. BULLS (types of rebounds gathered)
|C Off||C Def||F Off||F Def|
A note of caution. The above numbers are not “According to Hoyle” accurate. For instance, on several occasions I took phone calls and my attention was not sharp, and on other occasions I had a hard time identifying some of the Bulls players (I think I ended up generically giving the rebound to “Watson”). But more importantly, in retrospect I am not happy with my definition of “free” rebounds. (EDIT: Although my numbers are not neccessarily accurate to the player, I just checked the box score on basketball-reference and the numbers comport exactly with the offensive rebounding percentages from the game.)
My definition of “Free” Rebounds
I counted as “free” rebounds any rebound grabbed with no opposition within arms reach. By that definition, about 35% of the rebounds grabbed in the game where “free”. Most of the free rebounds were grabbed by the Bulls players on their defensive glass.
However, about halfway through the second half I started to dislike my definition of “free” versus “contested”. I was defining the exact same type rebound differently based upon circumstances outside the rebounders control. Let me explain.
In the second half of the game, the Bucks rarely contested their offensive boards. On the other hand, the Bulls always had at least one player in offensive rebounding position. As a result, on several occasions I was counting defensive rebounds for the Bulls that required a certain amount of energy expenditure (meaning, the player had to hustle in some manner to get the basketball) as “free” simply because no Buck chose to be in a rebounding position on that possession. On the other end the same type rebound was being classified as “contested” simply because Omar Asik or some other Bull was nearly always standing in the lane. I don’t know if that is a fair statistical distinction. How would the Bulls players who grabbed the so-called “free” rebounds know that no Buck was in the vicinity at the time of the act? They couldn’t.
Had I changed the definition of “free” to what I really meant to chart — “effortless” rebounds — (in other words rebounds that came directly to a player or rebounds that did not require the player to move or exert energy other than an unnecessary jump), then the number of so-called “free” rebounds would have been reduced drastically. Next Bucks game I am going to record rebounds in that manner. (Its better than watching the game).
Probably less of a problem than I imagined
I’ve been worried that Marginal Win Score numbers might be skewed by “effortless” rebounds falling to certain players in an uneven manner. I think now that I was worrying about nothing.
Andrew Bogut, for instance, grabs an inordinate amount of the Milwaukee Bucks rebounds. But he works much harder than any of his teammates to get those rebounds. Why shouldn’t he be rewarded for his effort? Same deal with Kevin Love.
Yes, there are occasions where a more assertive rebounder will grab a larger share of uncontested rebounds, but don’t you want assertive rebounders? Aren’t they a good thing?
Besides, after concentrating on the matter, I’m not even sure its worth distinguishing between “free” and “contested” rebounds. Generally speaking, the same amount of effort goes into a given rebound whether an opposition player is in the area or not. Completely “effortless” rebounds are rare, and so are rebounds where two opponents fight over the ball. The vast majority of rebounds require a certain degree of hustle and exertion, along with fortuitous bounces and superior positioning.
As a footnote, I’ve always thought it would be interesting to see what would happen if more teams ordered their frontline players, even their small forwards, to challenge for every offensive rebound. Would they suffer more fastbreak points given up? There’s evidence that is possible. But, I think overall the result would be positive, especially for poor shooting teams like the Milwaukee Bucks. I don’t know why the strategy has never been employed.