The Tank Watch (4/27/2012, final edition)

Earlier this spring, my coauthor Chris and I discovered that NBA teams tank a lot, especially teams in the first or second lottery position. This season, I’ve been tracking team performance before and after playoff-eliminated teams locked in to their lottery position. Once teams clinch their spot, there’s no incentive to tank anymore. We found that teams play much better after clinching. Here’s what things look like this year:

The Tank Watch

As I thought a couple weeks ago, the lockout bunched everyone up this year. There just weren’t enough games for teams to separate at the bottom. Only the Bobcats, Wizards, Timberwolves, Trail Blazers, and Bucks clinched their spots before the season ended. This doesn’t mean that teams weren’t tanking (see my post on the Cavs yesterday), but I can’t really test for tanking in a foolproof way. And, comparing pre/post clinch winning percentage doesn’t identify all tankers, since some teams may make personnel decisions that are irreversible (Exhibit A: the Warriors) and others just get so used to losing or are so terrible that motivation fades (Exhibit B: the Bobcats).

The one team that looks like a tank show for sure is the Wizards, who essentially clinched the second lottery spot a week ago, and rattled off five wins to finish the season. While the Wiz were playing all their stars down the stretch (since they had no reason left to lose), their buddies at the bottom (Cavs, Timberwolves, Warriors) were sitting everyone down or trading them. The big outlier of course is the Hornets, who, due to their league ownership, kept Eric Gordon alive and played GREAT down the stretch. At least it only cost them one spot in the end (they finished tied for third), and Hornets fans can be optimistic about next year with Gordon.

Now that we’re done with all that tanking, let’s get on to the NBA’s second season, where all the best players get to play, all the stadiums are full, and all the teams are above average.

Cavaliers, what have you done?

Yesterday, based on my past research with my buddy Chris, I predicted that the Wizards would take it to the Cavaliers last night. The Wizards were already locked into the 2nd lottery position, while the Cavs could still move up or down. Well, I was right. The Cavs looked good to start the game and then slowly faded away.

Our research shows that teams who haven’t clinched play worse than teams that have. In other words, they tank. However, we haven’t determined how they do it. Are players actually trying to lose, or is it all personnel decisions? Last night’s game gave us some evidence for the latter:

Here come the tanks

There’s a lot to decide in the NBA draft lottery still, with six teams bunched between 21 and 23 wins. The most unfortunate of these teams is the Hornets, who have won 62% of their games since they were eliminated from the playoffs on March 31st. They’ve beaten such quality teams as the Nuggets, Rockets, Jazz, and Grizzlies in that stretch — pretty much unheard of for a team in their position — and risen from possibly 2nd in the lottery to a potential tie for 5th (meaning they get the average lottery odds between 5th and 6th places). I’m sure this is due to league ownership (which forced the Hornets to bring back Eric Gordon). It’s a great “natural experiment,” actually, that provides further evidence of tanking by all other (individually owned) teams.

A few teams have clinched their lottery spots already: the Bobcats, Wizards, Timberwolves, and Trail Blazers. My research with my buddy Chris shows that these teams should pick it up now that there’s no reason to tank. Stay tuned for the final Tank Watch in a couple days. There’s a good test match up tonight between the Wiz and the Cavaliers — I expect the Wizards to take it to them. We’ll see if the clinched teams outperform the other playoff eliminated teams over the next two days.

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

The Tank Watch (4/11/2012)

Following up on my post yesterday tracking tankers the past few years, here’s the tank watch for the 2011-2012 season. Six teams have been eliminated from the playoffs so far, but no one has locked in their spot yet. We’ll see if the Bobcats stop their losing ways (13 in a row!) once they clinch the worst record and the tanking incentive is gone:

The Tank Watch

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

To tank or not to tank

Last week, I mentioned that my paper with my PhD cohort Chris was accepted for the poster session at the MIT Sloan Sports Analytics Conference. I’ll give the summary and some pictures today (you can find the full paper on my academic website). The project looks at the age old subject of tanking for position in the NBA draft lottery. We answer two questions:

1. Should teams tank for a better draft position?
2. How much do teams actually tank?

For the first question, we head right to the lottery. We are interested in the causal effect of obtaining the top pick in the draft. If the first pick is truly valuable, then teams should be willing to lose intentionally to get it. LeBron James, Tim Duncan, and Shaquille O’Neal were all first picks, but so were Greg Oden and Michael Olowokandi. We want the average value of all the first picks since the draft lottery took its current form in 1990.

Since there is some randomness in who wins the lottery,

Since the dawn of Linsanity

Since it all began for Jeremy Lin on Saturday, February 4th against the Nets, Jeremy Lin has shot 42-73 from the field (58%!) over four games. Lin’s shooting percentage his senior year at Harvard? 52%. His first four games as the starter for the Knicks are even more anomalous considering that he is only 3-14 from three point range. He shot 60% on two pointers his senior year, compared with 66% over the last four games.

You probably know what’s coming. That’s right, Lin has had a great start to his career, but also a lucky start. Although his performance has transformed the Knicks’ demeanor, don’t expect the insane shooting to continue. Teams will also start backing off on pick and rolls to see if he can reliably make NBA threes. If you still want to jump on the bandwagon, Brother Conor can tell you what to expect.

I also have great news today! One of my submissions to the Sloan Sports Analytics Conference was accepted for the poster session. The paper (available at my academic website, written with Christopher Walters) estimates the causal impact of NBA draft incentives on tanking as well as the causal impact of winning the NBA draft lottery. In short, we find that teams tank a lot — teams that can improve their draft position by losing have lower winning percentages than teams that can’t by about 15 percentage points. There’s good reason for all this tanking. After adjusting for team quality, winning the draft lottery provides a four year attendance boost (though only a small increase in winning percentage). I’ll explain the details in a future post.