Stats for Mr. Simmons, part II
A response to Bill Simmons,
|"I am convinced that Doc makes more substitutions per game and uses more lineups per game than any other coach in the league except possibly the Knicks. Is there any way to figure this out? And is there a correlation between a team's success and the frequency/infrequency of substitutions during a game? It just seems like the smarter coach figure out their five best players, play them as much as possible, spell them when they get tired with bench guys, then make sure those same five guys are playing the last 7-8 minutes of the game. I don't think this is rocket science. But Doc shuttles guys in and out like an NHL coach. Lemme know if this can be figured out."|
As it happens we've been sitting on a "coach substitution" article concept for a while, and yes indeed there are ways to figure some of this stuff out...
1) Lineups used |
2005-06 Season (thru Feb. 5th)
So first of all it's only fair to point out some obvious things: teams that make trades or have serious injury issues are much more likely to use lots of different 5-man units. Likewise, teams with lots of depth or bad teams trying to figure out a winning lineup with what they've got on the roster will experiment more often. Still when you check the units used against winning percentage, you'll find a -.39 correlation, which is a reasonably strong way of saying that more successful teams tend to use fewer different units.
This season the Celtics have used the third most array of 5-man units, and almost as many as they did in the entire 2004-05 season, so maybe there's something to Bill's argument that Doc tends to be a little quick with the substitution, even realizing the recent trade has a big impact on these numbers. Of course it's hard not to notice that the league leading Pistons have by far the fewest units used to this point.
Let's look next at the raw substitution numbers.
2) Number of substitutions|
Substitutions per game (2005-06 Season thru Feb 5th)
So Doc's Celtics have indeed made heavy use of substitutions, ranking 4th overall in most subs, and 3rd in first quarter subs, and 2nd in 4th quarter/overtime subs. Of course you can't conclude that it's a bad thing to be active on in game maneuvers, especially since none other than the defending champion Spurs lead the league. In fact, the correlations between pure number of substitutions and winning percentage is practically zero over the past two seasons.
So given the number alone may not tell the full story, how do we measure the effectiveness of a coach's "matchup maneuvering" in the course of games? You could look at the sub numbers for a team against its opponents, and indeed we did, but that wasn't very revealing. Instead we'd propose a couple of additional tweaks:
- team performance and % of game time with 0-5 starters on the floor
- team performance based on subs versus opponent subs at a given time
3) Starters on the floor|
It's an easy matter for us to count up the minutes and results with each various numbers of starters in the game:
How to read this table: We measured how often during each game the team had a certain number of starters on the floor, tallied this up into percentages, along with the unadjusted plus/minus. For example Atlanta has had 4 or 5 starters on the floor during 36% of their total minutes, with a -106 plus/minus under these conditions. [Keep in mind that moments when a team has "zero starters" in the game are often essentially garbage time when games are already decided.]
So, looking back at the Celtics you'll notice that as long as they have 4 or 5 starters on the court they've been okay -- a +1 plus/minus in 52% of minutes -- but when Doc has gone deeper into the bench for a five man unit, it's started to hurt: -51 in 26% of minutes with 2/5 or 3/5 starters, and -72 in 19% of minutes when he's down to one or zero starters on the floor. The Celtics do lead the league in "percentage of minutes played with exactly one starter on the floor."
Again, interpretation of these numbers is no simple thing, and can't just be pinned as cause and effect of the coach... we'll let Mr. Simmons reach his own conclusions.
The other side of the matchup is how your opponents play against you with the various levels of starters on the court:
OPPONENT unit distribution and results (how the opponents have done AGAINST a team)
|vs Golden State||49%||+61||34%||-20||15%||-40|
|vs L.A. Clippers||51%||-71||36%||-27||10%||-31|
|vs L.A. Lakers||47%||+15||40%||-115||11%||+39|
|vs New Jersey||45%||+29||38%||-6||14%||-28|
|vs New Orleans||49%||+86||37%||-7||12%||-39|
|vs New York||52%||+306||36%||+42||10%||-111|
|vs San Antonio||47%||-214||38%||-31||11%||-73|
This look perhaps leaves a little less wiggle room for Doc: the Celtics have been about even against opposing teams' when four or five of the opponent starters on the floor, but when the Boston adversaries have gone with lineups with three of less starters, they've outscored the Celtics by 124 points.
If you're getting creamed by lineups with 4/5ths or more of the opposing starters, you can make a case it's primarily a talent discrepancy (or your team going with the wrong starting five), but when you're getting clobbered by the opposing bench, then it's harder to shake the notion that you are getting beat in part from the other team winning the in-game substitution matchups.
The Pistons for instance pummel the opposition regardless of what the foes throw at them, excepting the 0/1 starter garbage time minutes. Phil Jackson's Lakers as another example have been barely above even facing opponents units with four or more starters, but once the opponent goes deeper into the bench, then the Lakers strike, outscoring their opponents by 115 against 2/3 starter lineups.
The next logical place to go with this analysis is to break down the actual substitutions and counter-moves as they happen, with ensuing results, and adjustments for how the game was going to that point. This however becomes increasingly complex (picture 6x6 grids), and while fascinating for us uber-stats freaks, perhaps a little more than is warranted here -- in other words we'll save it for another time.
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