Dec 14, 2014; New Orleans, LA, USA; Golden State Warriors forward Draymond Green (23) reacts after scoring in overtime of a game against the New Orleans Pelicans at the Smoothie King Center. The Warriors defeated the Pelicans 128-122 in overtime. Mandatory Credit: Derick E. Hingle-USA TODAY Sports
Starting this week, Nylon Calculus will be doing weekly power rankings, measuring how your favorite teams are doing as of the last week of the season. We know that everyone loves power rankings, and we’re determined to give the people what they want.
The idea of power rankings in general is that they represent a subjective “basketball-expert opinion” of where the teams are after each week of action, but as with everything here at Nylon Calculus, we’re seeking to bring just a bitt more rigor to the idea of ranking teams based on recent performance and trends. That said, the rankings are still mildly silly and totally imperfect, which I think makes them all the more fun.
Here’s the idea: basketball statisticians typically rank teams by their Net Rating, or, by how many points they typically beat opponents per 100 possessions. They do this for a lot of reasons, but largely because point differential is actually more highly correlated with long-term success in a season than win%. That, however, doesn’t make for a fun power ranking, in part because it doesn’t account for what teams have done recently.
So, we’re ranking teams by their Net Rating, and then adjusting that ranking based on the rate at which that rating has changed over the last week of basketball action. In short: we’re taking a team’s statistical record and adjusting it by how teams have performed recently. So, it’s like everyone’s power rankings, except that we use spreadsheets for ours[1. More specifically, we run a linear regression using their average over season other than the last week as the y-intercept, the whole season average as the last point, and the last week as every point in between. The slope of that regression line represents how the team has improved or crashed over the last week or so, and we weight the rankings using that information.]
We’ll work out a format for the rankings as time goes on, but for now: we’ll publish a chart with the rankings, each team’s Net Rating (found via the Nylon Calculus Team Efficiency by Possession stats) and the rate of change of that Net Rating. Afterwords, I’ll discuss the top five teams, bottom five teams, and the notable teams in the middle.
The first week of power rankings is quite a joy:
On the top 5 teams:
- Warriors: They’re the best team in the league, it’s not really close, and they’ve gotten better recently. That they’re so dependent on Curry, Thompson and Bogut might be a concern if someone were to get hurt, but otherwise, they’re a freight train that should terrify anyone coming near them, and they’re after the Bulls’ win record.
- Raptors: They might not have the sexiest win/loss record of the group, but they’re winning by a lot and not losing by much. A minor slide of late without DeRozan shouldn’t detract from the fact that this is a scary group.
- Grizzlies: The Grizz are just eating people alive behind MVP candidate Marc Gasol, and questions of whether or not these guys are legit are long gone: the Grizzlies will absolutely grit and grind you into dirt if you get in their way.
- Spurs: Don’t let the record fool you, this is a top 3 defense and a top 10 offense, and that’s without Tiago Splitter for most of the season so far and Patty Mills for all of it. They’ve dropped a few to some bad teams lately, but not by a lot, and they’re still largely killing teams. It’s tempting to start worrying about this team, but don’t. They’ll be fine.
- TrailBlazers: This team dropped a couple after a hot-as-hell 9-game winning streak, but this is a killer team with an elite offense and defense right now, and they’re making a serious big for contention as the season rolls on.
On the bottom five teams
- 76ers: Good lord, not only is this team maybe the worst of all time…but they’ve gotten worse lately, after winning two. The Hinkie tankathon continues.
- Timberwolves: The Wolves have looked good of late, and Wiggins in particular has been putting on quite a show…but this is just a bad team made atrocious by the lack of Rubio or Pekovic.
- Hornets: This team hasn’t gotten any worse lately…but it’s time to admit that this is just a really, really bad team, which is such a bummer. They could have been so much fun. It’s probably a good thing that they’re trying to move Lance Stephenson, who’s been an embarrassment.
- Lakers: They beat the Spurs! Kobe passed MJ for 3rd all time in scoring! They’re 7-7 with Nick Young back in the lineup! Yes! Well…sure. They’re still a really bad basketball team.
- Jazz: A fun team, with encouraging play on both sides of the ball that’s been getting better lately who still can’t really be competitive. At least their time is coming.
Other teams of Note:
- Mavericks: It’s yet to be seen if this team is legit, or if they’re just really good at beating up on bad teams. For now, we’ll lean towards the stats, but the possibility always remains that they’re a really beefed up version of last year’s Timberwolves, whose Net Rating was inflated all season by beatdowns of worse teams.
- Rockets: This team has basically been weathering its worst case scenario with Dwight Howard out and Trevor Ariza shooting so poorly, and yet they appear to be a top-level team with Harden going MVP-level insane. Watch for this team when everyone gets healthy.
- Thunder: It’s hard for the stats to capture how much better the Thunder is than the rest of the league right now with Russ and KD back, but rest assured, they’re coming. They want that title, and they might just get it.
- Clippers: This team has been getting better, but recent losses to the Suns and Grizzlies are concerning. This team might still have a ways to go.
- Wizards: John Wall is a madman, and this team is awesome, but the degree to which they’ve struggled against sub-par opponents is worrying. They could be title contenders, and they could be a 2nd round out. We’ll have to wait it out with this group.
- Nets: Despite being generally really bad, the Nets have had a couple really good wins, and that’s enough to bump them big in the regression model. It might be a blip on the map, or it could be something bigger.
- Cavaliers: Like the Clippers, the improvement is palpable, but a couple straight losses putting a dent in the momentum has to have more than a few Cavs fans sweating.
- Knicks: Oof.