Missed Free Throws and Rebounding Illuminate Hack-A-Strat
By Seth Partnow
April 22, 2015; Los Angeles, CA, USA; Los Angeles Clippers center DeAndre Jordan (6) shoots a free throw basket against the San Antonio Spurs during the second half in game two of the first round of the NBA Playoffs. at Staples Center. Mandatory Credit: Gary A. Vasquez-USA TODAY Sports
The kerfluffle over the intentional, non-desperation fouling strategy known (unfortunately) as “Hack-A-[insert name] has caused a great deal of interest in answering the question “is it actually a good strategy?” The answer is no, definitely no, well probably not[1. If the opposition doesn’t make it good strategy by say sitting DeAndre Jordan for Big Baby Davis to “counter” the fouling.] at least. A big part of why it takes a spectacularly bad free throw shooter to make this tactic worthwhile is offensive rebounding. Which, naturally, got me thinking about rebounding missed free throws more generally.
We’ll get to it in a moment, but a big part of the reason that going DJ Hackmode is a bad plan for the Spurs is the Clippers are unusually good at rebounding Jordan’s free throw misses.
In general, the defense has an enormous advantage in terms of securing missed FT’s. While during the 2014/15 season 26% of missed FGs were rebounded by the shooting team[1. With that number also heavily dependent on shot distance:
], only 11.5% of missed FT’s were offensive rebounded.[2. per SportVU rebound logs, which don’t take into account team rebounds which end up out of bounds.] Whether this stems from the inherent advantage of the free throw set up, or teams simply conceding the board in most cases is unclear. Possibly some of both. using the SportVU definition of “contesting” a rebound[3.
as when a player is within 3.5 feet of a rebound when it is secured.], the offensive team contested 43% of missed field goals, but only about 27.5% of missed FT’s. Intuition suggests that knowing the positional advantage given the defense in free throw situations, teams recognize the risk/reward ratio of chasing missed free throws is unfavorable (
chasing offensive rebounds and giving up transition opportunities are correlated
.) Perhaps, given how infrequently teams look to fast break off of free throws, the offensive team could stand to be a little more aggressive chasing these boards, but that’s largely speculative and probably would have minimal benefits – even a 50% increase in offensive rebound rate from that 11% to around 16% or 17% on free throw misses would work out to one extra board every ten games or so.
On aggregate, missed free throws are also corralled closer to the hoop than missed field goals. Free throw rebounds were secured 5.4 feet from the hoop on average while missed shots from the field were controlled 6.3 feet from the rim, on average. Unsurprisingly, offensive rebounds tend to occur further out on the floor than defensive rebounds on both free throws and field goals. However, the distance between O and D boards is much wider for free throws than field goals:
Distances in feet via SportVU data
As mentioned above, the Clippers are particularly adept at rebounding Jordan’s misses from the line. This is actually extremely surprising. First of all, the Clippers chase the lowest proportion of their own missed shots[1. “Chase%” is simply the number of offensive rebounds “contested” per the SportVU definition divided by the number available, as discussed here.] of any team in the league anyway at 35% (compared to NBA average of just over 42% and Minnesota’s NBA high of 46.1%). Jordan himself is by far their most aggressive and adept offensive rebounder – he “chased” 23% of all available misses, good for 22nd in the league among players with at least 750 minutes.[4. Hassan Whiteside led the league at 30.1% with Tristan Thompson and Enes Kanter in a virtual tie in second at 28% in larger minutes.]. The next most aggressive Clipper was Glen Davis, 106th in the league with a 12.1% chase percentage and Blake Griffin 122nd at 10.9%.[5. Spencer Hawes 6.1% chase rate reflects both on just how disappointing a signing he’s been as well as the problem with stretch bigs in terms of their inability to contribute on the offensive glass. Players who more actively pursued offensive rebounds than Hawes in include Jordan Clarkson, Kyrie Irving, Kyle Lowry and that monster Nick Calathes.]. With DJ at the line, it would be reasonable to expect the Clippers to get virtually zero rebounds as the shooter recovered his own miss only 1.9% of the time, a grand total of 125 times all season!
Yet, the Clippers almost doubled the league average, rebounding 21.3% of Jordan’s errant throws on the season. There isn’t any obvious general correlation between poor FT shooting and offensive rebounding however. Here’s a quick look at some of this year’s worst charity stripe bricklayers:
Of course, it might be a fluke. But last year, the Clips rebounded 20.6% of Jordan’s misses as well.
At least in Game 2 against the Spurs, it was notable how strenuously Griffin and especially Matt Barnes battled on the glass when Jordan was at the FT line, and the numbers bear this out. In general, the shooting team contested about 27.5% of rebounds from missed free throws this past regular season. Unlike their general tendency to not chase offensive boards, the Clippers contested 37% of rebounds from Jordan misses this season, but only 17.1% of misses from rebounds by all other shooters. In other words L.A. is fully aware that DJ might be missing, the opposition is counting on those misses and either the players themselves or on instructions from Doc Rivers and co. have decided to not make it that easy.