Basketball Stacks part 2: Rebounding

Yesterday, I posted a new idea for visualizing box scores: Game Stacks. While the first version did a good job of showing shooting percentages and turnover rates, it didn’t do a good job on rebounds. As my pops pointed out, Indiana had a big rebounding advantage over Michigan by the basic numbers (36-22), so it seemed wrong to rely only on the height of the stacks to determine who rebounded better. The reality: Michigan got more chances not because they rebounded better, but because they had more misses — and you have to miss to get a second chance. The height of the stacks just showed that Michigan got more offensive rebounds, even though their rebounding rate was terrible.

So, round two. Here’s the Michigan-Indiana Game Stack redesigned to capture rebounding:

Without play by play data, I had to keep the rebounding simple — I figured out the offensive rebound rate for each team:

Off reb rate = your off rebs/(their def rebs + your off rebs).

Then, I multiplied this rate by the relevant number of shots to generate the “Missed (O Reb)” category for each type of shot (the dashed regions). Each dashed/empty combo now visualizes the offensive rebound rate for the relevant team.

Now the picture is clearer:

• Michigan got a couple extra chances, but

The Tank Watch (4/23/2012)

Last week, the tanking was going strong. Only the Hornets had played well among playoff eliminated teams. My guess is that league ownership made them bring back Eric Gordon, and it’s about to cost them a lottery position after they won again in the last few days. They helped boot the Rockets out of the playoffs and Gordon had another superb game.

A couple other teams played well since the last Tank Watch. The Wiz have now beaten the Bulls, Bucks, and Heat in succession, but their spot is basically clinched, so their incentive to tank is diminished. One more loss in their last three games or a win for the Hornets will lock them in. The Pistons also posted a couple of wins, though over Cleveland and Toronto. Here are the updated numbers:

The Tank Watch

Tonight, we get a treat! The Bobcats travel to play Washington. Below is an incredible craigslist post that my buddy Tony sent me about this game (click to enlarge). Apparently there were zero tickets listed on Stubhub around 4pm.

The Tank Watch (4/17/2012)

‘Tis the season for tanking! Last week, there were six teams eliminated from the playoffs. The Bobcats and Wizards had lost quite a lot already since then, though the Hornets looked surprisingly good. The Hornets continue to look good, but everyone else is bad bad bad, and the ranks of the eliminated have grown. The Bobcats locked in the worst record last night, but it’s hard to imagine them winning any games the rest of the way, so I’m not sure they can be accused of tanking. They are just a terrible team.

The Tank Watch

The Hornets 6-3 record since playoff elimination is largely due to the return of Eric Gordon (they are 4-1 in recent games when he has played). However, would any team other than the LEAGUE OWNED Hornets bring back Eric Gordon

Who tanks in the NBA?

Tanking: intentionally losing in order to improve draft position.

After my PhD buddy Chris and I circulated our findings that NBA teams tank a lot, we’ve been asked a few times, “Which teams are tanking?” Today I offer a quick look at teams that have likely tanked.

First, a refresher: we measure tanking by comparing performance before and after playoff-eliminated teams “clinch” their lottery spot. In the last couple games of the season, many teams lock in their spot, so they no longer have an incentive to lose. Those games act as our control. The problem with doing it this way is that some tankers may keep trying to lose even after they clinch their spot. This could happen because teams shut down star players because of “injury” or just because teams develop a habit of losing.

So, the big caveat with the results below (and the results in our paper) is that we are almost certainly missing some tankers. Some teams

Basketball endgame

The Thunder and Warriors played a very entertaining game last night. All the stars showed up (Monta Ellis, career high 48 points; Kevin Durant, 33 points, game winning shot, close to a triple double). The defense wasn’t terrible — the Warriors especially made a bunch of tough shots. Close games like this are generally decided by luck, but there were two interesting decision points in the endgame where each team affected the odds:

Down one, should you shoot early or late?

With about 22 seconds left, down one point, the Thunder had Durant drive right to the hoop and go for a quick shot — air ball, but the Warriors knocked it out of bounds. On the next inbounds play, Durant pulled up immediately and banked in a (relatively) open jumper to take the lead with 16 seconds remaining. This gave the Warriors plenty of time for a rebuttal, and the Warriors announcers were confused that the Thunder didn’t run down the clock to take the last shot.

The Thunder clearly wanted to shoot quickly. Did this help or hurt their chances of winning? It gives the Warriors another chance

Hack-a-Howard in practice

A couple weeks ago, I argued that the hack-a-Howard strategy could work on a player who shoots 50% from the line. My post was timely; four days later, Mark Jackson instructed his Warriors to foul Howard repeatedly. Howard attempted 39 free throws (an NBA record) and made 21 (54%). The Warriors lost the game, and commentators hammered Jackson for ruining the flow of the game and being afraid to face up to the opposition. Magic coach Stan Van Gundy didn’t really complain but refused to foul 51% career free throw shooter Andris Biedrins in retaliation. However, the Warriors still had a chance to win with 3 minutes left against a far superior opponent. To me, that looks like a success.

What do the numbers say about Jackson’s decision? Well,

Shopping Rondo

Another story today about Danny Ainge shopping Rajan Rondo like the Greeks shop bonds. His main target has been Chris Paul, but Ainge went after Russell Westbrook over the summer as well.

The Celtics can barely field a team right now. They have three aging stars (Pierce, Allen, Garnett). I can see why Ainge wants to make a trade, and I agree that Paul would be an upgrade. But why would New Orleans make this deal?