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2012-13 starter-sub comparisons
Posted: Mon Jan 07, 2013 9:15 pm
by Mike G
Ed Davis of Toronto started 1 of his first 23 games, and then moved into the starting lineup for the last 12 games. Here are his unadjusted per-36 minute rates
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Ed Davis per 36 minutes, unadjusted
.61 mpg TS% FTA TSA ORb DRb Ast Stl Blk PF Pts X
start 31 .579 2.6 11.6 2.2 6.2 1.8 .9 1.2 2.6 13.4 24.3
sub 15 .574 4.7 12.4 4.8 8.1 1.6 1.2 1.6 5.2 14.2 30.0
TSA = 'true shot attempts' = FGA + .44*FTA
X = sum of Pts, Reb, Ast, Stl, Blk, -TO, per36
As a starter, he gets half as many FTA and PF, less than half the OReb.
Re: 2012-13 starter-sub comparisons
Posted: Mon Jan 07, 2013 9:35 pm
by Crow
It is either the right time to do this (making Davis a starter) and stick with it or too slow.
Valanciunas with an ok winshares per 48 but in bottom 25 in the league on xRAPM so far and has the lowest team win % while on the court.
Re: 2012-13 starter-sub comparisons
Posted: Tue Jan 08, 2013 3:10 am
by Mike G
I'm going to do this for players with at least 300 minutes as a starter and 300 off the bench.
The Spurs' Tiago Splitter started 2 of their first 24 games, and the last 12.
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Tiago Splitter per 36 minutes, unadjusted
.62 mpg TS% FGA FTA ORb DRb Blk TO PF Pts X
start 25 .587 9.8 5.6 2.1 6.4 1.4 1.8 3.0 14.5 26.1
sub 18 .655 10.8 6.0 3.0 5.7 1.2 2.2 3.6 17.6 28.8
Off the bench he got more shots
and hit a better percentage.
More OReb off the bench is partly offset by fewer DReb.
Ryan Anderson started for Orlando for a couple of years, and this year he's come off the bench in 16 of 33 games. Because he plays almost as many minutes off the bench, his stats are gotten with and against similar players.
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Ryan Anderson per 36 minutes, unadjusted
.67 mpg TS% FGA FTA ORb DRb Stl PF Pts X
start 35 .591 15.5 1.4 2.5 5.5 .7 3.0 19.1 28.4
sub 30 .554 17.3 2.3 2.7 4.6 .5 2.4 20.3 28.9
As a starter, he's shot better but not as often. He bucks the trend of fouling more off the bench.
I'm not showing categories that are virtually the same as starter and as sub.
EDIT: Atop the 'start/sub' column is the estimated fraction of opponents and teammates who have been starters in the player's minutes.
Re: 2012-13 starter-sub comparisons
Posted: Tue Jan 08, 2013 1:16 pm
by kjb
Mike: Can you post your "minutes against starters" estimator?
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 1:46 am
by Mike G
For starters and subs, the estimated avg % of starters on the court:
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mpg start sub
48 .67 .66
42 .71 .62
36 .75 .58
30 .79 .54
24 .84 .50
18 .88 .46
12 .92 .42
6 .96 .37
0 1.00 .33
It's assumed that starters average 32 mpg -- 2/3 of a game. Actually I've assumed 48.4 minutes in the avg game.
A starter who plays just a few seconds has played entirely (100%) with other starters on the court.
A guy who comes off the bench after just a few seconds and stays on the floor the rest of the game is playing against 2/3 starters, on avg.
Leading the league in estimated Sta% are Willie Green and Andrew Bogut (4 G), who have started every game but average just 18 minutes.
Warriors' rookie Kent Bazemore has been in 17 games, no starts, avg 2.1 mpg. His est Sta% is .35, the league low.
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 2:12 am
by v-zero
How did you derive this data, if you don't mind sharing?
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 2:25 am
by Mike G
It's a straight line deduction, from correct values at the extremes of zero and 48 minutes.
It does not account for quirks of coaching or player specialization.
For example, a backup center may specialize in fouling Dwight Howard early in the game. He plays relatively few minutes, but they aren't garbage minutes against other backups.
If other starters leave and re-enter the game at random points in time, and they average 32 minutes, you get this distribution.
The general equation is:
Sta% = (GS/G)*(1-.333*mpg/48.4) + (1-GS/G)*.333*(1+mpg/48.4)
The first half is for games started, and the 2nd half is games not started.
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 3:49 am
by Mike G
Cavs' rookie Tyler Zeller became a starter 10 games ago; not so much from merit, but because Anderson Varejao has been injured.
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Tyler Zeller - Cle per 36 minutes, unadjusted
.59 mpg TS% FGA FTA ORb DRb Ast Stl Blk PF
Start 34 .448 11.4 2.7 2.5 4.3 1.8 .7 1.4 4.0
sub 22 .486 10.1 3.1 3.3 4.8 1.3 .9 1.0 5.0
Now shooting more but worse, he scores at the same rate. Overall a wash.
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 3:49 am
by v-zero
How did you get the value of 0.33 for subs playing for almost no minutes?
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 4:04 am
by Mike G
I don't remember.
But the league adds up to .661 St%, which is 32/48.4
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 4:13 am
by v-zero
Fair enough, I'll have to take a look at using that at some point. Thanks.
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 12:00 pm
by Mike G
Also .33 is midway between what a random 1 minute appearance would be (.66) and what garbage time would be (close to zero).
While mop-up time against other 5 mpg players may be the anecdotal norm for 5 mpg guys, there are also the last-second shot and FT% specialists, the fouling specialists, etc.
Regardless of the formula, there will be individual outliers. But a straight line is likely pretty close for the vast majority.
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 12:29 pm
by v-zero
I have given this some thought. I like the logic, but the problem is that the total starter minutes faced by each player in the team won't add up to the opposition starter minutes under those values. The logic for the line for starters makes sense (assuming 32 minutes per starter on both teams) but that logic also defines the intercept and slope of the equation for starter minutes faced by backups under the constraint that total starter minutes faced must equal total opponent starter minutes. The problem then becomes a quadratic sum in minutes played by each bench player.
In the case where each bench player plays 16 minutes and there are five bench players (contrived but good for illustration) we get an equation for bench players of:
% starters faced = -2*minutes played/135 + 92/135
This is the only equation which will satisfy the constraints.
Interestingly in the limit as bench player individual minutes tends to zero (i.e. if you could play infinitely many bench players momentarily) then the solution reduces to:
% starters faced = 4/9 (+ (2/9)*minutes played, but since minutes played ---> 0, this will disappear).
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 3:56 pm
by Mike G
Hmm, ok.
So a lineup whose starters play 40, 36, 32, 28, and 24 minutes sum to 160 (32*5) starter minutes, but my formula predicts the team's equivalent vs-starter minutes sum to 158.2
This doesn't seem too bad. In reality, starters play much wider range of minutes than that, so being off by another 1 or 2% seems inconsequential.
Another large uncertainty is: Who is really a "starter"? The player who started the game, or the injured "real" starter he has replaced?
And in playoffs, starters may avg around 36 minutes. But I don't adjust the estimator for that. Everyone is scaled to the same standard, so it still serves my purpose.
Re: 2012-13 starter-sub comparisons
Posted: Wed Jan 09, 2013 7:45 pm
by Mike G
A few more bigs.
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Bismack Biyombo - Cha per 36 minutes, unadjusted
.67 mpg TS% FGA FTA ORb DRb Blk TO PF X
start 30 .465 5.7 3.9 3.8 7.1 1.6 1.3 3.0 18.9
sub 21 .492 6.2 2.1 2.9 6.3 2.9 1.6 4.0 18.4
Larry Sanders - Mil per 36 minutes, unadjusted
.66 mpg TS% FGA FTA ORb Stl Blk TO PF Pts X
start 26 .543 9.5 1.5 4.0 1.6 4.5 2.3 4.8 11.0 28.7
sub 23 .568 9.8 3.0 3.4 1.0 4.8 2.0 6.2 12.6 29.6
Marcus Morris - Hou per 36 minutes, unadjusted
.62 mpg TS% FGA ORb DRb Ast Stl Blk TO PF Pts X
start 28 .576 11.5 1.5 4.1 2.1 .6 .4 1.8 2.7 14.6 21.4
sub 20 .529 12.3 2.4 5.1 1.1 1.2 .7 1.1 4.2 14.1 23.6
Markieff Morris - Phx per 36 minutes, unadjusted
.60 mpg TS% FGA FTA ORb DRb Stl Blk TO PF Pts X
start 26 .553 13.3 1.5 2.4 5.3 .8 .9 1.3 3.2 15.4 25.9
sub 18 .421 14.7 2.6 2.8 4.7 2.1 1.3 1.8 4.7 13.3 24.6
The assumption is that when bench players do well, they often move into the starting lineup. When starters struggle, they go to the bench. Therefore, we suppose their output while starting should be better. But it doesn't seem to be so. The conclusion is that it must be easier to get shots, rebounds, blocks, steals against subs.
Assists and shooting% seem to be better with more starters on the floor. And fewer fouls, at least for bigs.