Posts Tagged ‘Plus-Minus’

The +/- Fun Zone

Tuesday, September 9th, 2014

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Back in April, Cavs: The Blog writer Tom Pestak took a ton of time to try and figure out which Cavs two man units were the most effective using plus-minus data for individual players and plus-minus data for two man units.  To make some sense of that data, a little math was required.  Plus-minus (PM) numbers don’t take into account how many minutes players and lineups played, so it needs to be adjusted to be looked at as a per 48 minute rate.  Once that rate is figured out it can be used for all sorts of fun stuff.  By comparing players’ expected PM/48 in lineups to their lineup’s actual on the court PM/48, you can see how well the players made magic together.  If the numbers match up, then the unit played average, but if the two numbers are drastically different, the unit either under-performed or over-performed.

Tom did this exhaustive exercise for two man units on the Cavs. The conclusion: everything commonly thought was more or less wrong.  CJ Miles was a beast, Andy V and Matty D made everyone better, and Kyrie only exceeded an expected PM/48 number when playing with Miles.

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Cavalier Combos – Searching for Synergy with Plus Minus Data

Tuesday, April 15th, 2014

The value of individual basketball players is coming into focus, and while individual player metrics are the holy grail of baseball, there needs to be a somewhat more holistic approach to team building in the NBA than the “moneyball” approach of maximizing the value of contracts by more rigorously modeling that which leads to winning.  I’m not sure how much GMs worry about chemistry in major league baseball.  Does it really matter if your center fielder and left-handed relief pitcher (that throws two pitches) get along?  There is very little on-field chemistry in baseball.  Obviously, the chemistry between pitchers and catchers is supremely important, but after that, your middle infielders should probably practice together?  (Right?)

Basketball is different, because players aren’t confined to specific roles in space and time.  In baseball, team-building from a positional standpoint and managing player roles is fairly obvious.  (I’m not implying that team-building or managing is simple – I’m saying that it’s easy to fill a hole at catcher.  You sign the best catcher you can afford and position him behind the plate.  You don’t really have to take the other guys on the field into consideration.)  Even if that lefty with two pitches is absolutely dominant, most managers know not to immediately promote him to starter and no GM is going to give him a 10 year 300 million dollar deal, even if he has a mind blowing BABIP.  He’ll probably mostly face lefties and bottom of the lineup righties.  Teams have figured this stuff out.

Basketball, in some cases, is losing the structure of traditional position roles.  Rule changes have morphed the game from an inside-outside attack to hyper-athletic guards initiating offense with dribble penetration and kicking out to spot-up shooters.  Stretch 4s and 5s are more common than back to the basket big men.  The most successful franchise of the past 15 years, the Spurs, more closely resembles a shape-shifting amoeba than a traditional box-and-1, house-shaped offense.  These changes necessitate a better understanding of chemistry and fit.  Assembling the greatest collection of individual talent does not guarantee greatness in the NBA, the 2012-2013 Lakers being the most recent example of this.

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