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

Basketball questions

I’ve been watching my fair share of basketball during the playoffs — very exciting, compelling series so far, despite the injuries. However, I have a few questions:

1. Why do you have to hand the ball to the ref before you throw it in? Wouldn’t it be much more exciting to let players throw it in as soon as they can get a ball, like a soccer throw in? Teams are allowed to do this after a made basket already. Add another commercial break to balance out the faster pace if that’s what it takes.
2. Why can you only draw a charge if you stay on the ground and fall over? The offensive player can draw a foul while jumping and keeping his feet, why not the defense? If the defender jumps, the best case is a no call. Referees have a big say at the end of basketball games, but it’s not a bigger say than baseball umpires, for example, who must make every ball and strike call. I think one of the reasons people persecute basketball refs (besides the Tim Donaghy scandal) is that the foul rules aren’t especially consistent.
3. Why do teams get so many timeouts, especially in the first half? They have lots of practiced plays that they can signal in from the sideline. I suppose that the endgame timeout flurries increase the tension on those individual plays, but the downtime in between is no fun, and I bet the rest of the game seems less important by comparison. Again, if we need a couple more evenly spaced TV timeouts or sponsors on the jerseys to compensate, I’m fine with that.

These are my questions. Do you have any answers?

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

The Celtics endgame

The Celtics are hanging onto the 8 seed for dear life. Last night, they got a big win over the Cavaliers (who are ninth) and managed to tie up the Knicks for the 7 seed. In Boston, most people realize that this group is done. I’m reminded of the Pistons in ’08-09; here’s the IMDB:

Endgame (2012)
PG-13 (66 games and 1 playoff round) – Sports Action

In 2008-2009, the Detroit Pistons are coming off six straight Eastern Conference finals appearances. However, their core players — Chauncey Billups, Richard “Rip” Hamilton, and Rasheed Wallace — are aging,

The Old Three and the condensed schedule

Lately, I’ve been arguing that older teams should rest their “more experienced” players as much as possible during the condensed season, especially in the fourth quarter of games that are out of hand. Regular readers might be shaking their heads at me after the Celtics’ games against the Cavaliers this week. In the first one, they gave up an 11 point lead in the last 4:24 of the game (they scored zero points). In the second, they nearly blew an 18 point lead in the fourth quarter.

However, I think these games are just more evidence that the Celtics should rest the Old Three in the fourth quarter with large leads (or deficits). Not only will it help in future games, but it might actually help in the current game. The Celtics have a strong bench, and the Old Three are, well, old and tired. They are prone to blowing fourth quarter leads with long scoring droughts. Whether early or late, Doc Rivers needs to find time to rest his horses, or they will be burned out by March.

Edit: I actually wrote this yesterday before the Celtics thumped the Craptors. In that game, they led by 28 points entering the fourth quarter, the starters all rested, and they ended up winning by 34. Progress, I say!

The Celtics take on Howard and win

It was a renaissance in Boston last night. Garnett was draining 20 footers, Paul Pierce was driving and kicking and hitting shots, and Jermaine O’Neal was putting the clamps on Dwight Howard. Everybody hustled. The defensive intensity never lapsed all game. To steal a line from NBA TV studio man Brent Barry, the Celtics’ “Jurassic Five” went prehistoric on the Magic and held them to a franchise-low 56 points. It was their first win over a team with a winning record, by 31 points no less.

Recently, I’ve discussed the efficacy of the hack-a-Howard strategy (or as Celtics TV mainstay Tommy Heinsohn puts it, the old “hack the Shaq”). The short answer is that Howard shoots too well from the line (59% almost every year, though lower so far this year) for a pure hack-a-Howard to be effective for most teams. However, hacking Howard only when he has the ball in good position

Steve Kerr agrees

In last night’s Heat – Lakers game, the Heat had The Bron in the lineup (despite being sick), but The Wade sat out with his ankle injury. Even without The Wade, the Heat dominated the game. Kobe shot a horrible percentage but took more shots than Pau “the Gas Man” Gasol or Andrew “Great Potential” Bynum (as usual).

The Heat led by 21 entering the fourth quarter. Still, Mike Brown left his starters on the floor until the bitter end. When Kobe entered the game around the 10 minute mark, announcer Steve Kerr admonished Brown to take all the starters out.