Projecting Success

Reed —  October 22, 2008

Now that we’ve been talked off the Kobe ledge and feel reasonably comfortable with Odom’s role, let’s move on to something less fun … statistical analysis. What follows is my attempt to weed through stats from last year and projections for this year and draw a few conclusions about the team’s likely performance. I recognize there are numerous flaws, big and small, in my assumptions and analysis, but nevertheless press on in the hope of adding some piece to the puzzle.

PER Differential

There are numerous bottom line statistics that measure individual performance, but I will focus on one I think is particularly illuminating – PER differential. “PER” tells us how efficient a player is in scoring, helping others score, gaining possession of the ball, and protecting possession of the ball. “PER allowed” tells us how efficient a player is in stopping his direct opponent from doing the same. “PER differential” (PER minus PER allowed) tells us the net effect of a player’s production on both sides of the court. In doing so, it weeds out players who appear productive by piling on box score stats, but are ultimately liabilities because they do so inefficiently. For example, in fantasy circles Josh Smith and Gerald Wallace are known as elite defensive players given their high combination of steals and blocks, yet they both allow a relatively high 18.2 PER allowed. By way of reference, Tayshaun Prince, who gets very few steals and blocks, has a sparkling 12.4 PER allowed. PER differential also helps us distinguish between offensive wonders and more well rounded players. Amare Stoudemire, for example, was one of the best offensive players in the league last year, but also one of the worst defensively – with one of the highest PERs and PERs allowed (27.6 PER, 19.2 PER allowed, +8.4 differential). Bynum, by comparison, while less flashy overall and less dominant on offense, had a stronger net effect (22.6 PER, 13.1 PER allowed, +9.5 differential).*

*(Note: for reasons I won’t get into here, the PER ratings listed by Hollinger and 82games.com are slightly different, with Hollinger’s always a fraction smaller. All PER references here are on Hollinger’s scale, so anytime I use data from 82games.com I normalized to Hollinger’s lower scale).

Team PER Differential

What I want to focus on here is using individual PER differentials to predict team success, particularly when it comes to the Lakers. There is a close (and obvious) statistical correlation between a team’s win-loss record and the cumulative PER differential of its individual players (taking into account minutes allocation). 82games.com lists the PER, PER allowed, and PER differential for each team by position. By adding up the five positional PER differentials, we can generate a total team PER differential. I did this and then mapped team wins as a function of team PER differential to measure correlation, as shown below.

Running a linear regression (not shown), we find the correlation coefficient between the variables is very high: .941. This is an obvious finding, as we already know that PER and PER allowed, given their focus on efficiency in scoring and preventing points, is a powerful statistic in tying individual to team success. Unsurprisingly, the Celtics and Pistons finished 1-2 in both team PER differential (+17.4, +14.4) and wins (66, 59). Also unsurprisingly, the Heat, Sonics, and Knicks finished bottom 3 in PER differential (-14.6, -14.3, -13.8) and with 3 of the 4 worst records in the league (23, 20, and 15 wins). The Lakers were third in the league in wins (57) and fourth in PER differential (+11.4). By calculating the slope of the regression line fitting the data, we can determine that each extra point of team PER differential is worth an extra 1.3 team wins (with a 0 differential tied to 41 wins, as we would expect).

What is more interesting than this obvious connection is the potential to use individual player PER projections to project likely team success. Recently, John Hollinger came out with his PER projections for every player in the league. By using these and forecasting minutes played for each Laker at each position, it is possible to come up with a rough estimate of total team PER for this season – and then use that to project wins. I did this. My methodology:

1. Project minutes played per game at each position for our 12 (likely) rotation players;
2. Use Hollinger’s PER projections and my minute allocations to determine the net PER for each of the five positions;
3. Because Hollinger does not project PER allowed, I used last year’s numbers for each player from 82games.com (thinking that our unchanged roster would lead to basic stability in defensive numbers), and calculated net PER allowed for each position;
4. Using the projected PER and PER allowed, I calculated the net PER differential for each position, and then the team as a whole.

The following spreadsheet shows the results (and makes it easier to understand the process):

As you can see, the projected team PER differential is +15.1. This (a) would have been second in the league last year, (b) is a significant improvement over last year’s +11.4, and (c) results in a projected total of 62 wins. A few notes:

Changed Assumptions

I tweaked the numbers in just a few cases. First, Hollinger projects Odom as having a 15.93 PER (down from 16.9 last year). Looking back at past seasons, it is apparent that Lamar has a much higher PER at PF than SF, but he will split time this year between the positions. Thus, my spreadsheet reflects this as I give Odom a 13.73 PER at SF and a 16.89 PER at PF (which, taking into account that I project him playing 2/3 of his minutes at PF, leads to a net PER of Hollinger’s 15.93). Second, Ariza’s data from last year was too small a sample size so I used his defensive numbers from 2007 with Orlando when inputting his PER allowed.

Roster Thoughts

• The Lakers have great talent and depth. Thanks to Kobe, Gasol, and Bynum, we project to be very strong at three positions (SG, PF, C) and among the league leaders in two (SG, C). At SF, PF, and C we not only have a star starter (Kobe, Gasol, Bynum), but backups with positive PER differentials (Sasha, Odom, Gasol). This is a rare blessing.
• The main improvement over last year comes at PF and Center, which is unsurprising given that we expect a full season out of both Bynum and Pau at those spots.
• As expected, SF is a mess. There are simply too many bodies to give anyone meaningful minutes. Based purely on the numbers, we should focus our minutes there on Ariza and Kobe (and to a lesser extent Odom), especially as Sasha is very productive at SG and worthy of more minutes (shifting most of the SF minutes to Ariza and Kobe and giving more time to Sasha would lead to an increase in 2-4 projected wins). Ariza is the only true SF (Kobe excepted) with a positive differential (+2.19). However, based on the preseason, I am optimistic that Radmanovic can be more productive than projected. As we’ve all discussed, at some point Phil needs to ride the most productive players at SF and sit the others.
• If Hollinger is right and Fisher regresses while Farmar improves, more of the PG minutes should be transitioned to Jordan. Last year they split at 27 for Fisher, and 21 for Farmar; I projected an even 24/24 this year, but it might make sense to give Jordan a little more than that.
• Our best lineup on paper (Farmar, Kobe, Ariza, Gasol, Bynum) has an incredible PER differential of 28.0 (if that lineup played all 48 minutes of every game, the team would be projected to finish 77-5). Last year, the Spurs had the best 5 man lineup in terms of PER differential (Parker, Finley, Ginobili, Thomas, Duncan) at +31.3. The Celtics had the second best at +28.8 (Rondo, Allen, Pierce, KG, Perkins). The difference between those teams was that the Celtics’ production did not fall off the cliff when they went deep into their bench, and the Spurs did (in addition to the fact that PER really disfavors pure defensive specialists like Bowen). Clearly, this Laker team has strength in both being able to sport very effective 5 man lineups, and in having depth to not lose significant production when it goes 8-9 men deep in the rotation (we have seven players who project to have positive PER differential; many teams have multiple negative players starting). But, there also remains room to create a much more dominant 5 man lineup by improving (whether internally or via trade) at the PG or SF position.
Hollinger projects PER decreases for most of our players: Fisher (sizable), Kobe, Sasha, Radmanovic, Odom, Walton, Gasol, and Bynum. Basically every rotation player on the team except Farmar and Ariza. I buy his arguments for Fisher, Kobe, and (to a lesser extent) Sasha. Some of the drops are significant and puzzling: Gasol and Bynum. I understand that they will share responsibilities and numbers, but PER is also about efficiency. I’d be surprised if their mutual presence seriously harms each of their individual PERs, especially with Bynum young and developing. I think Walton bounces back from a poor showing last year and Radmanovic has room to improve. Overall, I think Hollinger’s projections are a touch on the low side for the team. If I’m right, and many of these players just hold steady with their production (in terms of efficiency) from last year, the team would project closer to 65 wins.

Methodological Problems

This analysis is obviously rough and there are a few problems with my analysis, including: (1) failure to take into account how roster changes will affect individual PERs (although I understand Hollinger’s projections did so, as shown by Pau and Bynum both having lower projected PERs than last year); (2) using last year’s PER allowed stats (there was simply no way to accurately project changes for this year, but I hope our basic roster and style stability will lead to a small error size); (3) my minute allocations do not take into account possible injuries (although I do try to project on the low side – e.g. Bynum may play more than 30 minutes a game by the end of the year, but he’ll also probably miss a few games); and (4) most importantly, statistics (including PER) have significant, inherent limitations and overlook things like chemistry, effort, health, attitude, style synergies, etc. This analysis is intended to be interesting and spark discussion, not be an end all projection of the team’s performance this year.

Questions

We don’t need statistical projections to tell us this is a very talented, deep Laker team. With health, the forecast of 62 wins is reasonable, even in the increasingly brutal West. How many wins do you predict? What players have the potential to make a leap in their production and efficiency this year (like Sasha did last year)? Who might regress? Is Hollinger right that both Bynum and Gasol will lose a little individual efficiency when playing together and see a drop in their PERs this year, or is it possible they could become more efficient (I, for one, think they could both shoot over 55%, which would make our offense historically dominant)?

–Reed

Reed

Posts

33 responses to Projecting Success

  1. PeanutButterSpread October 22, 2008 at 3:34 pm

    Repost:

    Sorry, I have a question that might seem really stupid, but

    What does it mean when the Lakers waive Joe Crawford and CJ Giles?

    I know they aren’t on the Lakers roster, but since Crawford is a draft pick, does it mean the Lakers have renounced his rights? Or does it mean they will sign him (and Giles) to the D-League like they did with Coby Karl last season?

  2. I believe it means both are waived, and the lakers don’t retain their rights at all. This is fairly typical for second-round draft choices, unfortunately.

  3. Great post Reed. I agree with your assessment that the projection should be closer to 65 wins.

    (Although I think will be hit with injuries this year and end up with closer to 57 wins)

  4. I can’t stand Hollinger, but Reed, you are outstanding.

    I have to think that Fish, coming off a career regular season, will have to come back to earth a little, thus I agree with a drop in his numbers.

    Odom’s impact can’t be told through numbers, but I agree his will dip too, mainly because of minutes and Phil’s usage of him as an initiator.

    I think Vlad is in line for a big season, along with a return to respectability and contribution for Walton, so I don’t think they’re numbers will drop.

    As far as Pau and Drew. I think some numbers for Pau (assists and turnovers) will go up, and some (rebounds, points, minutes, fg%) will go down, simply by his new positions in the tri. Drew however should be able to improve in several areas statistically and also is inline for a big season (health provided)

    Overall, I’d be happy with a healthy team going into the playoffs, with home-court advantage throughout. With the East getting better and Boston obviously focusing in on the playoffs, I think the best record in the leauge very well could be had with 58-60 wins.

  5. I don’t buy into this PER thing at all, but what you did is really worthy reading and logical, despite my reservations towards PER.

    Just that Pau and Bynum’s PER will probably go down as Hollinger projected because #1 Bynum only played in the beginning of the season, when teams are less prepared #2 Both played without each other as the second focal point and sharing playtime on the court will lead to decreased PER (but perhaps improved PER allowed) #3 I’m not sure, but Pau’s PER while with the Grizzlies could not have been that low either, meaning that his could suffer too.

    Still… all I am shooting for is a competitive team that can get into the PO and do well once there. Not really too worried about the regular season as long as we get PO berth.

  6. I think the numbers tell us a lot about minute allocation, but less about our best lineups. For example, the best 5 man lineup would be Farmar, Kobe, Ariza, Gasol, and Bynum. That would definitely be a strong team, but observation tells us that Farmar and Ariza are most effective with the running/chaotic style of the second unit, not the deliberate, pound the ball inside mantra of the starters. You need both stats and traditional observation to maximize production.

  7. Bynum’s stats from last year are probably on the low side, relative to his true ability, because he made such an improvement during the season. SO his stats this year will (IMO) be a little higher. Gasol will probably lose a little because of having Bynum playing with him.

  8. Wow – nice work, Reed!

  9. I think Vlad will have a statistical leap in PER. I’m not saying his D will get any better but having the two bigs available at the same time for some of his minutes and having at least one legit big on the court at all times, coupled with Vlad just getting the system down a bit better, I think he’ll be able to take advantage of the open shots from the outside and the lanes created by opponents scrambling to cover for what the bigs will do.

    This team can afford to lose a player or two, be it to trades or injury. Having to sit players, even significant contributors, will have very little effect on W-L unless its one if the bigs or Kobe. I’m thinking 61 wins, a #1 seed through out the playoffs and another shot at the Leprechauns. Christmas will be telling.

  10. Does it seem like we are missing a defensive stat? Blocks and steals are important defensive tactics, but leave me unfulfilled.

    This PER stuff, I can’t intuit it. It’s kinda shifty. But PER differential seems like a step in the right direction for a defensive stat.

    Two players shooting 55% and playing legit minutes would be awesome. Kobe could use a little rest, especially at the beginning of this year. This team can be *scary* good. And the Mamba is on our side.

  11. Stats like the contribution of individual PER to team PER, related to Wins Produced, divided by E=MC2, ad infinitum, are a waste of time … when it comes to really understanding how the NBA game works.

    Team W’s are the important thing in this League not the other stats.

    Individual and systemmic mismatches are what create the open shots which kill a team and result in either W’s or L’s.

    If the Lakers can stay healthy … they are going to win 70+ games this season and another Chip.

    If they can’t avoid the injury bugaboo, however … there are plenty of other top flight teams in the League this season, several of which have enough of the right stuff to win the championship.

    It is going to be a terrific season.

    The Celtics are going to miss the contributions of James Posey in the Playoffs … which should mean a return to the Finals for the Detroit Pistons, under the re-vamped leadership of their rookie head coach, Michael Curry.

    If the Lakers heed the instructions of the Zenmaster their team is simply too powerful not to win the title this year.

  12. I disagree that stats are a waste of time. Statistics can help us spot trends and can help project (not predict)what to expect in the future. Of course the problem with stats is that they can be interpreted by different people to mean different things.

    Cue rant.

    That is my problem with Hollinger. He has inate biases (everyone does) that color is interpretation of the stats. And then he hides behind his numbers and tries to claim innocence.

    That said, I think that Reed has done a fantastic job of taking the stats and interpreting them. We know he has a bias (being a Laker fan), but knowing that helps us understand and appreciate his position. Kudos!

  13. 11. It’s just a means v. ends distinction. Stats tell us why certain players are effective and why certain teams win. Thus, if we can predict with some certainty the stats of a team or player, we can project a team’s probable performance. You are right that mismatches, open shots, etc. are important to teams winning games. But a stat like PER tells us a lot about what players and teams create and exploit mismatches, which teams box out and rotate defensively, which teams protect the ball, etc. — for those teams and players shoot higher %’s, rebound at a higher rate, don’t turn the ball over (the components of PER), and stop their opponents from doing those things efficiently (PER allowed). I’m not saying it’s a perfect stat, far from it, but it tells us a lot and can be used to help us understand why, in part, some teams and players are so successful.

    10. The missing defensive stat is “PER allowed.” It looks beyond mere blocks and steals and tells us how well a player precludes his opponent from scoring, shooting well, creating assists, rebounding, etc. Bynum and Kobe were fantastic at this last year and thus led the team in PER allowed.

  14. I believe the is Vlade’s 3rd year in the triangle system. Hasn’t Phil said it takes two years to learn the triangle? I would really doubt those who discount any improvement for Vlade this year. His bball IQ isn’t better than average, but, then again, if it were he would take less than 2 yrs to learn the triangle. I predict his overall measurement by Reed’s stats would be noticeably improved this year.

  15. Peanut Butter Spread October 22, 2008 at 10:38 pm

    #2. thanks for the explanation.

    And I’m just sad for CJ Giles and Joe Crawford, especially since he was our draft pick this year …it just doesn’t seem right to waive him, at least sign him to the D-League, kid has promise.

  16. Reed, this is brilliant, thank you for all the time and energy you put into this.

    Defensive stat to note: it’s not as sexy and clear as steals or blocks, and would be useless through at least the first third of the season, but I’d like to see how a player held his defensive assignment compared to his season average (in PER).

    Example, Kobe has a season average PER of 23, but when he goes up against Bowen, Bruce holds Kobe’s per to 16. Bowen’s sat line could read 2 steals, 1 block, +7 DP (defensive per).

  17. Related

    Kevin Pelton previews the Pacific. His numbers show the Lakers as the best team in the league.
    http://www.basketballprospectus.com/article.php?articleid=425

  18. Reed, this was a good post that helped explain the reasoning behind the numbers. In fact I don’t remember a blog with anything quite like this post. I just ‘feel’ what you basically explained using statistics (PER) of what the Lakers will do this year, great.

  19. Reed,

    Fantastic analysis. I want to echo the comments everyone else here has posted about your ability to take a lump of coal like the PER system and get something useful out of it.

    I also want to key in on your comment that this Lakers team has the potential to be historically dominant on the offensive end. With the scary kind of efficiency Kobe has been showing in this preseason, the possibility of (as you pointed out) and Bynum and Gasol boosting each others’ efficiency in pretty much everything besides rebounding rate (where I assume they take the biggest hit in Hollinger’s model), that first unit will be pretty difficult to keep from scoring on any possession. Then, taking into consideration the pace the second unit is going to play at, even if it’s somewhat less efficient, I think we could see more than a few 130+ point games for this team.

    Also, if the first unit builds a lead, the opposing coach will have to be reluctant to leave his first unit out to try and chip away at it against the bench mob, running up and down the court and tiring out their stars.

    I’ve always wondered what sort of effect that has, especially on a team like last year’s Nuggets, who, adjusted for pace, were actually a good defensive team and a poor offensive team, despite the fact that nobody in their rotation (including Camby) were particularly great on-ball defenders. Camby’s great at help D, and the team managed to force a fair number of turnovers, but I can’t help but wonder if their main defensive strategy was just to run up and down the court really really fast to tire the other guy out…

    Anyway, back to this year’s Lakers. If we can manage a top 8 or 10 defense (about where we were last year), the regular season will be insanely fun. If a full year of Bynum and Ariza (knock on wood) can improve that by a couple of places… well, it’s not good to salivate this much before the season even starts.

    Now, if we can only figure out how to counter Boston’s Triangle kryptonite D. Or “bump” Tom Thibodeau…

  20. I’m confident LO can be a good sixth man, but I don’t know if he can be a great one. I don’t know if he can have the impact of a scorer like Ginobili, but if he plays efficiently(esp. by taking advantage of his time on the court w/ Pau), he can be our Detlef Schremp.

    A terrific all-around player, check out Detlef’s lines from 90-91, and 91-92, his 6th Man award-winning seasons.

    http://www.basketball-reference.com/players/s/schrede01.html

  21. Reed,
    Great, great post. I love the use of PER as a meaninful statistic (just not the end all, be all that some tout it as at times) and love the PER against as a measuring stick for effective defenders. I think your post brings a statistical validity to why we can achieve a high level of success next season (as proven by pointing out why teams like Boston and Detroit were strong in the reg. season last year).

    As for some of the ideas presented by Hollinger himself about the performance, measured by PER, for our players next season, I think he under estimates some of our guys. First, I will say that I expect Fisher to regress some, and that Sasha, if playing more minutes (which is likely), may not be as efficient as last season. Sometimes it’s hard for medium level players to sustain efficiency when they have a minutes increase. I know that Sasha actually played better last season as his minutes rose, but we’ll see if that trend continues if he’s earning those minutes over an entire season. As for his other predictions, I’m not sold that we see a decline in PER for Pau, Bynum, and Kobe. Only time will tell on this, but I think we’ll see better efficiency numbers from these players even if their minutes decrease. The threat of them all on the floor together is something that defenses will have to adjust to and if our chemistry is strong (which I think it will be) then I think we’ll see stronger performances in shooting %, assists, AND rebounding (as I think that our defense will improve and force more misses that our guys will gobble up). I could be wrong, but I see us getting better next year, not leveling off or getting worse.

  22. I’m with Darius on this one, as much as Kobe’s minutes decline and Pau and Bynum ‘share’ their offensive production, their efficiency and D-efficiency will likely improve. Even though we have stable variables–coach, system, players,etc.–with the addition of Andrew Bynum, a lot changes.

    The triangle is a hell of a system. It encompasses a variety of talents, physicallities, and intellects into a basketball process. Bynum/Gasol play the triangle differently than Gasol/Odom. Their offensive results will vary, obviously, but really what affects all ten players on the court is our combined threat quotient. For instance, Kobe saw a lot of double teams last year; the opposition “cheating”, if you will, because our other offensive weapons would not fire. But with Bynum and Gasol on the court, all that changes: everyone’s a weapon and everyone will see less defensive pressure.

    Similarly, Odom’s numbers will vary. He will be on a different team, although, with more consistencies from last year than most players see when they are ‘benched’. His tandem will mostly be Gasol/Odom or Bynum/Odom. While other assets change around him, like less Kobe, more Sasha, and Farmar is his point man, he benefits by playing against bench players most of the time. On the same note, Farmar and Ariza will see their defensive and offensive numbers improve because they’re practically playing with a starting line-up. As much as people might think Odom’s numbers will decline, I think he wins with the change in playing style. The second unit will run, score much more in transition, and run through Odom.

    Kurt, you posting a game thread for our rivals, the Thunder?

  23. errrr, Bobcats.

  24. http://www.latimes.com/sports/la-spw-farmar23-2008oct23,0,7784867.story

    Great article about Farmar’s maturation.

    This exerpt from the article was weird to me because I’ve been taught that way too:

    “Farmar had been taught different fundamentals while playing for Woodland Hills Taft High and at UCLA, including to never jump in the air to make a pass, or dribble to the corner to start an offensive set, or to pick up the dribble before a pass or shot.

    But all that is OK under Jackson.”

    I know Phil coaches differently, but not THAT different. I was surprise.

  25. 24/25. Yes, later today it will go up. Also will have a lot of links around the Web from the last couple of days.

  26. I’m a huge Laker homer, but have grave concerns about Bynum’s health. I kniow he looks okey now, and I know his injury isn’t like a microfracture (hello Greg O), but he still has not played many minutes and certainly not over 82 games plus 20ish in the POs. I’ll believe in Bynum in, say, late March.

    I would like Kobe to play 30-35 mins per.

  27. Oh, and Vlad is on probation, too. I just haven’t seen enough from him to get excited.

  28. Just an update, I will be on the Loose Cannon’s show (570 am) in Los Angeles just after 2 p.m. Listen in as I try to get a word in edgewise with that group.

  29. New Bobcats game post up.

  30. What I find rather amusing is Reed uses Hollingers’ PER and has the Lakers winning 62 games while Hollinger has them winning 57 !
    Last yr Hollinger underestimated the West by some 14%,so a similar underestimation would have the Lakers w/@64 wins,which is very close to Reeds work. Assuming normal NBA health,I’d predict @ 63-64 wins for the Lakers.
    Keep in mind Hollinger strongly values offensive rebounds,high percentage shooting and steals. He only uses box score stats and that leads to some distortions. For example offensive fouls are included(as turnovers) as negatives,but drawing an offensive foul is not included. One could argue that drawning an offensive foul is even better than a steal. While a steal usually leads to a transition-hence higher % shot-an offensive foul drawn impacts the opposition player’s ability to stay in the game. Which would you rather have,Kobe getting stripped twice in the first few minutes,or getting called for 2 charges?

  31. Great point Stephen.

  32. Reed says, “Stats tell us why certain players are effective…”

    It’s better to use “how.”

    There’s a difference between “how” and “why” my friends.