My work projecting the NBA using xRAPM has lead to some interesting conversations with readers and other interested NBA fans. It also lead to further discussion with Nathan Walker over of The Basketball Distribution, who was the person who inspired me to start doing these projections in the first place. Through an e-mail exchange, he provided me with a method, using the age and prior year xRAPM of the player in question, which projects xRAPM for the next year very well. The R² is .74. Given that this method seems much more scientific and how startlingly good the results are at predicting future performance based on such simple inputs, I will be re-running my projections for the 8 teams that I’ve already done and then continuing on using the method Nathan provided going forward. The minutes projections will still be done using the Kupfer method described previously here. I plan to try to bang out the remainder of the projections within the next few weeks and then adjust based on strength of schedule and HCA at the end of the process and right before the season gets underway to try and have the best possible projections for you. Basically, we’ve got a brand new recipe and it’s time to get cookin’.
Oh and go follow Nathan on Twitter, since he’s awesome and helped me do a better job than what I was doing.
That bit I wrote yesterday about the Los Angeles Clippers and Brooklyn Nets having the best offseasons of the summer? Yeah, scratch that one. That was a glaring oversight on my part, because clearly no team in the league had a better offseason than the Houston Rockets, who, after years of tireless searching, finally landed President of Basketball Operations Daryl Morey’s version of Ahab’s White Whale: a top 5 player in the league. That player, Dwight Howard, can be nauseating at times with his desire to play the crack-up, the clown, the immature teen who’s actually a late 20’s man, but the talent and production have never been a question. Howard had jokes all through his time in Orlando, and yet, he was always worthy of consideration as an MVP candidate as he came into his own.
In 2010–11, Howard reached the peak of his powers, leading the league in xRAPM (yes, even ahead of LeBron James); this just two years after Howard dragged this rather rag-tag bunch to the NBA Finals, going through James’ Cavs to do it. That season, which saw Howard working as a top 5 player by xRAPM (and most other metrics you might want to look at), was just the beginning of Howard’s dominance in Orlando, as he finished in the top 2 every year from then on, even including his injured and distracted final run in 2011–12 with the Magic. That last season in Florida, disappointing as it was, paled in comparison to the depths of disappointment Howard’s turn as a Los Angeles Laker inspired. Howard came back from his back surgery too quickly. He became frustrated over trying to fit in with Mike D’Antoni’s offense. He fell off, and to the eyes of many, he stopped trying as hard. For my own part, I believe he was limited mostly by injury and the lack of floor spacing the Lakers supporting cast had on offer to open up lanes for him to roll to the basket off of pick and rolls. He also, stubbornly, insisted on getting touches in the post, despite his dominance as a rolling finisher and his relatively pedestrian skills on the block. He was also clearly unhappy, as he bristled beneath Kobe Bryant’s unflinching iron fist and joyless assassin’s mentality. Even with all of those issues facing him, Dwight was in the league’s top 6 players by xRAPM, coming in with a still very impressive +5.54.
And now? Dwight gets to have fun again. He’ll have his new buddy Chandler Parsons with whom to goof and clown. Morey has made sure that the floor with remain spaced for Howard with bargain priced shooters filling out the wings. Oh, and Dwight will also get to play with James Harden: the league’s best shooting guard, even at his tender age of just 23, and one of the very best pick and roll triggermen in the game. This was the formula for Dwight’s dominance in Orlando, only Harden is so much better than anyone Howard was tasked with playing with in Orlando that it’s scary to wonder just how good these Rockets can be.
So what do the numbers say? The first projection I ran used Dwight’s performance last year as the baseline. By that measure, the Rockets appear to be a 55 win team.
A playoff team, probably worthy of a round of homecourt advantage, even in the stacked Western Conference and a team that could contend for a title, even with a less-than-what-he-once-was Dwight. But what if Superman returns? What if Dwight is really, really back (as I suspect he will be: I think he just needed to get healthy)? Well, then the Rockets start to look a bit like world-beaters.
62 wins, with a healthy, Orlando-level Dwight. This is the stuff of Rockets fans’ dreams. It’s not inconceivable, and it might not even be all that unlikely. Fans were right to criticize Howard’s relative lack of effort last year, but moving forward, there’s a lot of reason to believe the effort will return (as will, unfortunately, the terrible jokes), the fit is better, and Howard should be a year healthier. Add it all up, and I think that Superman returns for Houston this year. Maybe Dwight will even get his wish to “be epic.”
Update:This post from Brett Koremenos over at Grantland makes the point that the Rockets could potentially play Asik alongside Howard for extended minutes. I only projected Asik to play 15 minutes a night as a result of Dwight’s arrival, but if you bump Asik’s projected minutes up to 25 minutes a game, the Rockets become a 59 win team with last year’s version of Dwight and a 65 (!) win team with the Orlando version of Dwight. I doubt they reach quite that high, if only because Dwight and Asik together on offense would put them in less than optimal roles (spacing issues being the primary problem) which would have a negative effect on their respective offensive xRAPMs. On the other hand, the two of them on defense together would be seemingly almost impossible to score on in the paint.
The San Antonio Spurs will not be going away next year. They will be towards the top of the heap in the Western Conference. Tony Parker’s excellence, Kawhi Leonard’s emergence, and Tim Duncan’s seeming lack of senescence ensure that. For the rest of the league that just saw the Spurs come within a miracle Ray Allen corner three of winning the title, this should be quite scary indeed. But just how good will the Spurs be next year?
In 2013–14, by xRAPM, combined with my interpretation of Jeremias Engelmann’s adjusted-plus minus aging curve and minutes projections courtesy of the Kupfer method, the Spurs project as a 55 win team. That’s a drop off of 3 games and that’s significant, but there’s reason to doubt its accuracy. This projection expects Tim Duncan and Manu Ginobili to both decline quite a bit. The Big Fundamental, though, looked basically like the same guy he’s always been this year all the way through the playoffs. The mind reels at his ability to continue to slug it out with Father Time to a draw. Duncan’s the exception and not the rule, though, and if Manu’s playoff run is any indication, he may decline even more than this projection suggests, which may counteract Timmy’s refusal to surrender to age. The regular season’s not the end game for the Spurs, though, just as it wasn’t this year. They will rest their core guys (as these minutes projections suggest) and they will be fresher than just about any other team come playoff time- and have no doubt, the Spurs will be back in the postseason this year. Once they get there, I expect Tony Parker to keep the ball humming to the right spots, Duncan to continue locking down the paint, and Kawhi Leonard to grab seemingly every rebound within 15 feet of him. The Spurs will contend, again. It’s over when they say it’s over.
So, the Clippers. What an offseason, huh? The Clippers had arguably the best offseason in the league this year, save what Brooklyn was able to cook up 3,000 miles away on the opposite coast. To recap: they were able to acquire two capable wing players (Jared Dudley, J.J. Redick) in exchange for a player (Eric Bledsoe) who, despite his massive potential and above average production, simply didn’t figure to play enough to justify what he’ll need to be paid, because of the top 3 player in the NBA playing in front of him (that’s Chris Paul, you guys). They replaced that potential with the less talented, but still capable Darren Collison, the once and future CP3 understudy. They retained Matt Barnes and drafted another 3 and D wing in Reggie Bullock. They’re flush with those types between Redick, Dudley, and now Bullock. Maybe too much so. But, on the plus side, they acquired Doc Rivers to manage all those wings and fix a rotation that works, for the relatively piddling price of a late first round pick. Oh, Byron Mullens is along for the ride, too, but he’s not very good at much besides taking and missing a lot of jump shots while simultaneously being tall. So, really, who cares about Byron? What do the numbers have to say about what we can expect from the Clippers after their offseason to remember?
57 wins. That’s improvement over this year’s 56 wins, but not much. Why don’t the Clippers look better? Well, they lost Eric Bledsoe who, as it turns out, was a +1.61 player in xRAPM and played 1500+ minutes for them last year. Jared Dudley and J.J. Redick had lower xRAPMs than Bledsoe, as did Darren Collison. Additionally, the Clips lost Lamar Odom who was a +.82 xRAPM and replaced his 1600+ minutes with the terrible Byron Mullens and a combination of wings who will likely be worse than Odom was last year, at least by xRAPM. Plus, Jamal Crawford and Matt Barnes project to decline relatively significantly, while Blake Griffin somewhat offsets that with a pretty significant improvement, as he climbs towards his peak years. Subjectively, this prediction seems like it could be a bit low, as the Clips had the MOV of a 59 win team and most NBA heads had them improving this offseason. Plus, Doc Rivers is in a different class as a coach than Vinny Del Negro. But I present the numbers here for you, dear reader, to ponder over.
Sidenote: At the end of all this projectin’ I will try (if I have time) to incorporate the schedules of the teams, the strength in projected MOV of each team, and the value of home court advantage for each team (as determined by Evan Z over at The City) in order to come up with the most accurate predictions that I can. Also, you should check out the ESPN NBA Forecasts, as they are going up over the next few days. Lots of smart people’s thoughts aggregated together = wisdom of crowds = awesome analysis.
The Oklahoma City Thunder were, arguably, the league’s best team last year in the regular season. They did not have the best record, as Miami finished the year with 66 wins to OKC’s 60, but the Thunder played a much tougher strength of schedule and actually underachieved relative to their margin of victory (MOV) by about 4 games. As I mentioned in my post projecting Miami for next year, the Heat actually significantly overachieved relative to their expected wins based on their MOV and also faced the league’s easiest schedule. Unfortunately for the Thunder, in their first round series against the Rockets, they lost Russell Westbrook for the rest of the season with a torn meniscus suffered on this (dangerous) play by Patrick Beverly:
The Thunder managed to win that series without Westbrook, their second best player and a top 10 player in the league. They were stopped in the second round by the Grit & Grind Memphis Grizzlies. Kevin Durant simply had to do too much against one of the league’s very best defenses and, despite a heroic effort, he came up just a bit short.
This offseason, the Thunder lost Kevin Martin (+.33 xRAPM) to free agency and really did not replace him. They signed Ryan Gomes, who was not in the league last year and was hurt a lot and just not very good in 2011–12 the last time he played. They also drafted Steven Adams and Andre Roberson. RAPM projections really do not like Adams and I don’t have any sense of how good Roberson will be, but given his status as a second rounder, betting on him to help or play many minutes on a team contending for a title is a very iffy proposition. In fact, in my minutes projections, the two new Thunder rookies are not set to play at all.
One young player I do expect to play quite a few minutes, if only out of necessity, is Jeremy Lamb. The ostensible centerpiece of the James Harden trade, Lamb will need to take on some of the minutes covered by the departing Martin. He projects to improve over his very poor performance by xRAPM next year. He’s still sub-replacement level by these projections, but he needs to be developed and he shouldn’t be so bad that he can’t be out on the court. It’s likely returning guard Reggie Jackson will also see an increase in minutes as he backs up Russell Westbrook and plays alongside him in spots, again to mitigate some of the loss of Martin. Neither Lamb nor Jackson projects to be near the overall contributor that Martin was last year and as a result the Thunder will take a step back in overall quality. Last year the Thunder played like a 64 win team against a more difficult than league average schedule. Next year, they project like this:
The Thunder figure not to fall off too much, as they project here as a 60–61 win team*, assuming a league average schedule. Why won’t they fall off? Well, Serge Ibaka, Russell Westbrook, and Kevin Durant are just 24, 25, and 25 years old respectively. They all project to improve. Those improvements alone help a great deal with the loss of Martin. But the Thunder, in all likelihood, probably won’t be quite as good as they were last year. They may win just as many games, or more, than they did last year, depending on their strength of schedule, but again, they underachieved last year and played a tougher than average schedule. They will be, in all likelihood, from an objective perspective, a lesser club next year. But they will still absolutely be one of the very best teams in the league and one of the top contenders to win the title. Having two top 10 players in the league, each at just 25 years old, does wonders for your ability to weather the loss of role players.
*I projected Ryan Gomes as a replacement level player at -2.5 xRAPM. In 2011–12, he was a -4.4 in xRAPM for the Clippers, but he was hurt quite often and I believe it damaged his effectiveness quite a bit. The previous year, where he was much healthier, Gomes was a much more useful -1.7 xRAPM. I think Gomes will probably be closer to -2.5 than the -4.4 that he was in his last year in the league. However, if you project Gomes to be that terrible again, the Thunder still project as a 59 win team against a league average schedule.
Continuing my seriesprojecting the 2013–14 NBA regular season using xRAPM and minutes projections, today I’ll be discussing the Indiana Pacers.
The Pacers had a very strong starting group last year. According to Basketball-Reference, the Pacers starting five-man unit was fourth in the entire league in Net Points per 100 possessions among lineups that played at least 300 minutes together, clocking in at a sterling +12.1 points per 100 possessions. Over the course of an 82 game season, a +12.1 MOV translates to a roughly 72-win team. The Pacers’ five of George Hill, Lance Stephenson, Paul George, David West, and Roy Hibbert played over 1200 minutes together, ranking them as the second most played 5 man unit in the entire league, trailing only the Oklahoma City Thunder’s starting five of Russell Westbrook, Thabo Sefolosha, Kevin Durant, Serge Ibaka, and Kendrick Perkins. The Thunder’s starting five only managed a (still incredible) +10.7 Net Points per 100 possessions. Basically, the Pacers’ starting five players was arguably the best in the entire league, given the relatively large sample of minutes they played together and their excellence when they were on the floor.
The Pacers’ problem was that their bench was pretty terrible. They gave pretty significant minutes to sub-replacement level players like D.J. Augustin, (-3.68 xRAPM), Gerald Green (-3.21), Orlando Johnson (-3.36), Sam Young (-4.94) and Dominic McGuire (-2.93). Well, this coming year that will no longer be the case. With the exception of Orlando Johnson, all of those guys will not be on the team next year. Instead, they’ve been replaced by C.J. Watson, Chris Copeland, Luis Scola, a returning Danny Granger, Donald Sloan (another below replacement player, but hey, you can’t win them all), and rookie Solomon Hill (who projects to be just above replacement level at -2.3). In addition, Orlando Johnson projects to be better this year, as he progresses upward in his career trajectory, though he’ll still likely be below replacement level. The Pacers starting five has gotten significant reinforcements. How much better will this make the Pacers?
Well, there’s one more thing to worry about and that’s just how good will Danny Granger be when he returns to the floor. I have no way of knowing what Granger will look like in xRAPM should he return healthy. I don’t know if he will be the roughly +1 xRAPM player he was in just 5 games this year or if he will look more like the +2.5–3.0 player he has been over the two years prior. Tendinosis is a scary injury. So, I ran the projections using Granger’s bad numbers from last year and then again with a possession-weighted average of Granger’s last few seasons adjusted for his 30 year old age. Up first, what the Pacers look like with a significantly reduced (like last year) Granger playing about 63 games.
Next year, the Pacers with a less-than-peak-effectiveness Granger look like a 55 win team. Given that they won 49 games last year, this might seem like a disappointing improvement considering how much better their bench has gotten this offseason. But a six-win improvement is very significant. That’s a 12% increase in wins. In addition, Paul George’s minutes projection is lower than his actual minutes from this past year by a shade under 400 minutes. So if George is able to play as many minutes as he did last year, the Pacers could be even better. Speaking of the Pacers being better, what would they look like if Granger comes back and plays like he did at his peak effectiveness?
The Pacers now look like a 57 win team. This may be understating things for the Pacers, too. If Granger is playing like he did 2–3 years ago, chances are that means he’s basically healthy, so he’d likely play more than the 63 games he’s projected to play here. That would push the Pacers win total even closer to the very top of the Eastern Conference. The Pacers, with their revamped bench and the return of Danny Granger to the rotation, look to be a team firmly entrenched in the top 4 of the Eastern Conference. It looks more or less like a four way toss up for which team will be the East’s best in the regular season. For Pacers fans, the more encouraging part of this exercise is looking at how much better their bench now is, to complement their returning starting five, which was the league’s best last year. In the playoffs, the Pacers’ ability to shorten their rotations and play their best five players for longer periods of time is the reason, along with their superior interior play, that the Pacers were able to take the Miami Heat to the brink of elimination. The Pacers now have a bench with competent players to play minutes in the playoffs and not be totally overwhelmed. That change could be the difference between their falling short this postseason and an NBA Championship in the 2013–14 season.
The Miami Heat are great. They have been since their big 3 players joined up together 3 years ago. They will almost certainly be great again this year. The question is just how great will they be. Let’s take a look at what the Heat looked like last year from an xRAPM and xWARP perspective.
The Heat here look like a 59 win team. So why, then, did they actually win 66 games? Well, there are two major reasons for this. First, they played the easiest strength of schedule in the league — part of that is that they didn’t have to play themselves, part of that is that they play in the weaker Eastern Conference, and part of it was just lucky for them. Second, they won more than their share of close games. It might be that they were a team that was better at executing late in close games, and while there is definitely some of that for this team, these sorts of overperformances tend not to reoccur year-to-year.
Going a little deeper on these two factors, the Heat had an SOS of -.84 according to Basketball-Reference. This means their opponents were, on average, .84 points worse than league average per 100 possessions. Over the course of an 82 game season, that produces an extra 2 wins using the simple margin of victory (MOV) to wins calculation (2.54*MOV + 41 = Wins). In addition, the Heat overperformed their MOV (+7.87) by about 5 games. The Heat, then, performed like a 59 win team had they played a league average schedule. As a result, we should expect some regression to the mean for this team, even without any major changes. Additionally, the Heat have a lot of older (30+) players who project to decline slightly. So what does the projection say for the 2013–14 Heat?
The Heat of next year look like … a 59 win team, again. This result should not be terribly surprising. Although they recently amnestied Mike Miller, which will hurt a bit as he is an above replacement level contributor and they have no way of adding anyone else who would be as good as he was and is, the Heat will have a full season of Chris “Birdman” Andersen, who was a pretty amazing per minute contributor (+5.19 xRAPM) in his role for the Heat this past season (and also in the playoffs). As a result, even with a bit of a projected per minute decline in productivity for Birdman (down to +4.79 xRAPM), due to his age, the loss of Mike Miller should not be too damaging in terms of the Heat’s overall regular season record.* Where the Heat may ultimately most miss Miller is in the playoffs when rotations shorten and the loss of a top 8 rotation player will be magnified. The Heat have come quite close to defeat in the playoffs two years in a row and losing Miller is not nothing. He was quite safely above replacement level and he’s one less reliable floor spacer the Heat will have in their playoff rotation. Fortunately for the Heat, they still have LeBron and shortened rotations tend to favor the team with the best player in the world.
After projecting the Bulls, Nets, and Heat, thus far, all three teams look to be very, very strong with the rankings as 1. Nets, 2. Heat, and 3. Bulls. The projections are so close, though, that any number of things could tilt things. If my minutes projections are off, if some major contributor declines much more or much less than I estimated, or if there is a major injury or Jason Kidd turns out to be a lousy head coach, any of these things could upset the projections quite easily. The big takeaway is that all three of these teams should be absolutely great and the top of the Eastern Conference is going to be a total slugfest.**
* I only projected Birdman to play 17.6 minutes per game for next year’s Heat. This seemed appropriate to me, as that is his career average, and he played 15 MPG for the Heat in this year’s playoff run, so I doubt that Coach Spo plays him much more than that, especially given how much the Heat like to keep Bosh at the 5. I think Birdman’s per possession effectiveness is maximized in that role, as he is able to go totally full tilt with the energy and hustle in his limited minutes. So playing him more than that runs the risk of him being worse overall per possession.
**As an added footnote, Hickory High has just released a post today with their full RAPM projections for this year’s rookie class, for this year. I will be using those numbers from here on out. Go read that post, though, it’s great stuff. They don’t change the projections for the Bulls or Nets really at all, as for those teams rookie’s the numbers I used previously look to be about the same and I had projected them all to play such few minutes that they didn’t really change the expected wins of either team.
Last time out, I explained the method I would be using to project the records for the 2013–14 season. There was a lot of dense explanation that I won’t cover again in this post. You can re-read it here. This post will be about updating the method to take into account new research from Jeremias Englemann on aging and RAPM and also to try to project the new rookies entering the league based on projections done over at Hickory High by Cole Patty, Jacob Frankel, and Jam Draper. Finally, I’ll show the updated results for the Bulls and also discuss what this off-season’s biggest splash-makers, the Brooklyn Nets, should look like provided their health holds up.
First up, aging. Aging affects performance, obviously. It cuts both ways. As players get stronger and smarter when they are younger, they tend to perform better year over year. Eventually, usually at around age 30 or so, they start to decline, due to the negative affects of aging and a lifetime of basketball played. Jeremias Engelmann wanted to know the effects of aging on average performance under RAPM. So he did some research and came up with the following graph:
As a result of that graph, I decided to add adjustments to the xRAPM of each member of every team based on the expected change in their performance based on the change in their age. Here are the numbers that I used, based on an eyeballing of the graph provided by Jeremias:
Age 19 to 20 = +.6
20 to 21 = +.4
21 to 22 = +.4
22 to 23 = +.35
23 to 24 = +.3
24 to 25 = +.15
25 to 26 = +.1
26 to 27 through 28 to 29 = 0
29 to 30 = -.1
30 to 31 = -.2
31 to 32 = -.2
32 to 33 = -.3
33 to 34 = -.4
34 to 35 = -.4
35 to 36 = -.6
36 to 37 = -.6
37 to 38 = -.75
Second, I wanted to try to get a projection of what rookie performance for this year might look like. I looked around for projections in RAPM of the incoming rookie class and the closest thing I found was 4 years in the league RAPM projections done by the guys at Hickory High mentioned earlier. Unfortunately, 4 year in projections don’t help me for projecting the league for this year. So I subtracted out the RAPM performance bumps those players would have expected to receive via the aging curve over the 3 seasons following their rookie year from their 4th-year RAPM projections to try to approximate a guess as to what their production might look like for this year. It is, admittedly, a janky solution. But it’s the best I could figure for the time being. If I find a better solution, I will change things and post updated results.
Okay, now on to the more fun stuff: projecting the Bulls and the Nets with the updated method.
The Bulls look more or less the same as I had previously suggested. Tony Snell’s projection is much worse as the 4-year RAPM projection had him as one of the worst projected players drafted. Erik Murphy looks about the same as I had projected him last time. I don’t expect either of them to play significant minutes so this change had little effect on the Bulls estimated win total. I believe Derrick Rose will play his normal level of minutes as he has had plenty of rest and should be back, better than ever. Rose, Jimmy Butler, and Marquis Teague project to have improvements based on their ages which helps the Bulls, while Carlos Boozer, Mike Dunleavy, and Kirk Hinrich all project to decline slightly. The rest of the major minutes contributors should be more or less the same. As a result, I have the Bulls pegged at about 58 to 59 wins, which is right in between where my two earlier projections of 57 and 60 wins would suggest. So the age adjustment did not make a huge difference for the Bulls.
One team for whom the aging adjustment did matter was the Brooklyn Nets. Prior to age adjusting their roster, the Nets looked like a 63 win team. This is how their projection shook out:
After adjusting for age, however, the Nets still look great. They project as a 60 win team, provided they stay reasonably healthy. I made a point of keeping Kevin Garnett’s minutes low relative to his career average, as he has stated in interviews that he can no longer handle the heavy minutes loads that he has been tasked with his whole career. The good news, for Garnett and Nets fans, is that it looks like he will not need to be asked to handle such heavy minutes. The Nets appear to be a juggernaut in waiting. Here are the results with the age adjustment:
I have seen the Nets compared to this year’s Lakers as a top-heavy team full of oldsters assembled together to take a shot at a title, with the implication being that the Nets will fall apart just as spectacularly as those Lakers did. I think this is wrong because these two teams could not be more different in terms of roster construction. This Nets team is DEEP. Eight of their top 10 players in projected minutes played are positive xRAPM contributors and ALL of the top 10 in projected minutes played are above the replacement level of -2.5 in xRAPM.
By way of contrast, the 2012–13 Lakers gave over 1300 minutes to Earl Clark (-4.14 xRAPM), 1175 minutes to Steve Blake (-3), plus over 1500 minutes combined to Chris Duhon and Darius Morris (-3.95 and -4.93, respectively). Steve Nash was merely above average (+.7) when he played and on top of that, he was hurt often (hence all the minutes for Duhon, Morris, and Blake). This year’s Lakers squad had little depth and suffered significant injuries to key contributors (Pau Gasol, Steve Nash, and Kobe Bryant) and saw Dwight Howard play when he likely should have been recovering from back surgery. Dwight was awesome (+5.54), but he wasn’t as great as he can be (+8.8 in 2011–12, +9.7 in 2010–11). This is not to say that the Nets will necessarily be much healthier at the top than the Lakers were, but it is to say that they are better prepared to handle injuries thanks to their far superior depth.
If these Nets stay reasonably healthy and Jason Kidd is worth a lick as a coach, they represent a significant threat to the Heat, Bulls, and Pacers at the top of the Eastern Conference. They may even be the favorites to win the regular season Eastern Conference crown, under this analysis, if not in Vegas. Speaking of Vegas favorites, the Miami Heat will be next up in this series of posts.
I really like advanced basketball stats and trying to learn as much as I can about them. As a result, I spend an inordinate amount of time perusing the threads over on the Association for Professional Basketball Research (APBR) message board. Through my reading there and elsewhere (usually following links I found there), I have come into contact with a statistic called regularized adjusted plus-minus or RAPM for short.
Adjusted plus-minus is essentially an approach that attempts to use on / off data to determine how much a given player contributes to the margin of victory (or loss as the case may be). It does this through regressions on lineup data found in play-by-plays to determine the +/- of a given lineup over a given shift that they were out there. The regressions then spit out numbers which show how much a player is likely worth + or — per 100 possessions. The problem with adjusted plus-minus in its regular form is that is quite noisy and that there are collinearity issues. Collinearity, in this context, just means that there are often players who play together a lot and thus it is hard to disentangle their value in +/- from one another. Additionally, the sample sizes of minutes played by each lineup are small, which leads to the aforementioned noisiness in the data.
RAPM improves upon the regression-based approach of standard adjusted plus-minus by using a technique called regularization or ridge regression. It’s basically a high level math technique that statisticians use to deal with the problems presented by the normal adjusted plus-minus type of regressions. It leads to much less noisy, more accurate results.
Finally, xRAPM, the subject of this post, includes a box-score based statistical prior to further inform the player ratings and thus improve the predictive effectiveness of the metric. All of this is a long-winded way of saying that xRAPM is the most accurate +/- metric that exists for predicting future results of which I’m currently aware. As a result, it’s the method that I will use to project each of the 30 teams’ records in the NBA next year, based on estimated minutes, and impact of the players on each team. The numbers for xRAPM are available here. (Thanks to Jeremias Engelmann for publicly providing the data).
xRAPM is a great tool for projecting, but I wanted to translate it to something more tangible to the common fan. Wins. After talking to Nathan Walker of the Basketball Distribution on Twitter, I learned a way to convert xRAPM into WARP (wins above replacement player). In short, xWARP (for short) examines the number of wins a player contributed over what an available replacement would provide in the same number of minutes. I set replacement level at a xRAPM of -2.5 points per 100 possessions in xRAPM. Nathan uses -3.5, according to our Twitter conversation, but the end result of projecting is the same.
Now, for the true purpose of this post. I will be examining every team in the league by looking at their xWARP for this past season and trying to project their xWARP following their offseason moves. I’m starting with the Central Division and the Chicago Bulls, because they’re my favorite team, I know them best (and can best guess minutes distributions), and because their offseason is more or less done (save a cheap big man or guard signing, which are likely to be replacement level players themselves, so have basically no impact on this math).
The Bulls this year were a team that outperformed their point margin by about 3 wins. Their MOV was a relatively small +.32. Subbing that into the standard MOV to wins converter equation from The City’s Advanced Stats Primer ( 2.54*MOV+41 = wins), the Bulls should have won about 41.8 games, so basically 42 wins. Instead, the Bulls were statistically lucky. They won 3 more games above their expected win total. A lot of that probably had to do with Marco Belinelli’s 3 ridiculous game winners. But basically, the Bulls were better than expected based on how close they played their opponents. This was not a 45 win team, it was more like a 42 win team. Here are the numbers:
By xWARP the Bulls look more like a 41 win team but the point is roughly the same. They overperformed their expected win performance level based on what amounts statistically to luck.
So the Bulls just signed Mike Dunleavy Jr this year, a good player, and they get their MVP, Derrick Rose back, so surely they will win many more games this year, right? Short answer: yes. But let’s look at the numbers.
I projected the Bulls’ minutes distribution for next year using a combination of a method described here by Kevin Pelton formerly of Basketball Prospectus and currently of ESPN.com Insider, based on a study by basketball statistician Ed Kupfer and my own intuition about how many minutes a player would play per game played based on rotations. Pelton describes the method as setting the expectation for a player starting at 76 games and going down about one game for each six missed the previous season and one for each 20 missed two years ago. Two years ago was a 66 game season, so I used 16 games instead of 20 games when calculating that number of games in the projection. I did two projections. I projected what the Bulls would look like with Derrick Rose playing just 61 out of 82 games (the number according to the Pelton-Kupfer projections) at his usual 36 minutes a game. Then I looked at what they would look like if Rose matched his career high in minutes played of 3026 minutes (a/k/a the scenario where he’s truly 110% in Rose-speak). In the latter scenario, I subtracted Rose’s additional minutes from Kirk Hinrich and Marquis Teague, the back-up point-guards. Here are the results for the less optimistic, (probably) more realistic numbers for Rose playing about 2200 minutes over the season:
The Bulls here project as … a 57 win team. After not having their MVP for an entire year and winning 45 games (and really being more like a 41–42 win team) a 57 win season with him playing nearly 2200 minutes would be great for Bulls fans and should signal return to the East’s top tier. What about if the Bulls get 110% super-healthy Derrick Rose and he plays 3026 minutes?
Congratulations Bulls fans! With a very healthy Rose, you’re looking at … a 60 win team! Adding about 800 minutes to Rose’s minutes projection yields an additional 3 wins in xRAPM. Basically, if DRose is back to the level that his old self and able to play 2010–11 level minutes, then the Bulls will look very much like the team that won 62 games that year and 50 out of 66 the following year. Even if Rose is only able to go 61 out of 82 games, the Bulls still look to be a high 50 win team. Of course, there are caveats, in all of this. Luol Deng and Carlos Boozer have both been declining by xRAPM for 3 years in a row. They may further decline. Rose may not be at the level that he was before his injury right away. There could be another major injury to a significant piece of the core group (*fingers crossed, knocking on wood that this doesn’t happen*).
But there are potentialities that would allow the Bulls to look even better. Jimmy Butler improved quite a bit over his rookie xRAPM of -.7 to a solid 1.04 this past year and he’s young enough he should continue to improve. Joakim Noah is still just 28 years old and is in his peak years, so he will likely remain the same or slightly better. Marquis Teague may improve more than I have estimated (I assumed he would be at least a -3 in xRAPM this year, slightly below replacement level still but not as bad as his terribad previous season xRAPM of nearly -5). The new rookies may be better than the -4 xRAPM level that I have pegged them at, just to be safe, and may get more minutes if they outplay the older players, though with Thibs at the helm, I highly doubt the rookies get many minutes, as is clear from my minutes projections. Finally, Derrick Rose may be better than ever. He was on a solid upward trajectory prior to his injury and he’s had a long, long time to improve on his jump shot and other skills. He’s been able to observe and watch for defensive tendencies. Now he’s coming back after taking his time with his recovery and feels 100% right. I’m certainly not going to rule out him possibly ratcheting up another level. I’ve learned not to doubt the man.
After all that dense reading, I leave you with a whole bunch of awesome DRose highlights:
As noted above, the Nets have been no stranger to spending since Prokhorov took over, but this is something else entirely. With this summer’s moves, the Proker is showing the rest of the league that money simply does not matter to him at all. He’s become the NBA’s rogue, chaotic force, hell bent on sending a message that he will build a winner, no matter the cost.
The Nets now have a starting five featuring 2 future Hall of Famers and rounded out with All Stars at every other position. Their bench now looks similarly stacked. There’s backcourt scoring and floor stretching in Jason Terry. Kirilenko’s great defense and all around solid play everywhere else. Reggie Evans’s ability to hit the glass. Andray Blatche’s post scoring and occasionally solid defense. Plus, capable point guard play holding it all together from Shaun Livingston. The whole bench has roles that fit together reasonably well with solid contributors.
The Nets have built a deep roster that should allow them to rest the old dudes from Boston and keep them fresh for what should be a deep playoff run. If Jason Kidd proves up to the task of managing the egos and crafting an offense that emphasizes ball movement, as he’s promised, the Nets could be incredibly dangerous. It’s all because Mikhail Prokhorov is determined to show the rest of the NBA that this league deserves a better class of owner and he’s gonna give it to them.