Page 4 of 14
Re: 2012 predictions
Posted: Wed Dec 21, 2011 12:43 pm
by EvanZ
Here are my projections in a Google spreadsheet:
Re: 2012 predictions
Posted: Wed Dec 21, 2011 1:03 pm
by DSMok1
How did you create the minute projections? Purely based on depth charts?
Also--what set of RAPM's did you use. Are the EZpm values projections?
Re: 2012 predictions
Posted: Wed Dec 21, 2011 1:11 pm
by mystic
Thanks Evan for sharing.
RAPM looks like prior informed (6 yr), the ones said to be the best for prediction.
Re: 2012 predictions
Posted: Wed Dec 21, 2011 1:17 pm
by EvanZ
DSMok1 wrote:How did you create the minute projections? Purely based on depth charts?
Also--what set of RAPM's did you use. Are the EZpm values projections?
Minutes are just educated guesses based on depth charts from ESPN, Rotoworld, and looking at pre-season box scores. I may make some changes up to the last minutes. For example, Gortat just broke his thumb last night. Curry sprained his ankle yet again last night, might be out for a while.
RAPM is the one that Jerry says is the best predictor:
http://stats-for-the-nba.appspot.com/ranking_rec
ezPM is mostly an average between the last two years, but I tweaked some ratings here and there for players based on my gut. If you look at the win totals for both sets of projections, there are not major differences. The R^2 between the RAPM ratings and my "massaged" ezPM ratings is 0.44.
Rookies were assigned a -2 rating. Replacement level was set at -3.3 for players that were not rookies and did not have over 500 possessions or so in either of the last two seasons (otherwise, I used their ezPM).
Re: 2012 predictions
Posted: Wed Dec 21, 2011 1:41 pm
by DSMok1
If you're interested, I generated (a while back) rookie and sophomore year APM projections based purely on pick number. Interestingly, age of draftee mattered 0, so there doesn't seem to be any "potential bonus" or anything.
Note the high Stdev, particularly for lower draft picks.
I would project all players below -3.5 projection as -3.5, or what I consider replacement level. (They won't be playing if they're below about that number).
These were generated presuming that, if some of the players didn't get playing time, that we were looking at the top portion of a normal distribution for that draft pick. So if 30% of pick #42 players got PT, I assumed they were the top 30% of a normal distribution at that draft pick.
First Rookie, then Sophomore Year:
Code: Select all
Pick Expected Stdev
1 0.51 1.65
2 -0.22 1.65
3 -0.67 1.65
4 -1.01 1.68
5 -1.28 1.72
6 -1.52 1.76
7 -1.73 1.80
8 -1.92 1.84
9 -2.09 1.88
10 -2.25 1.92
11 -2.40 1.96
12 -2.54 1.99
13 -2.68 2.03
14 -2.81 2.07
15 -2.94 2.11
16 -3.06 2.15
17 -3.18 2.19
18 -3.29 2.23
19 -3.40 2.27
20 -3.51 2.31
21 -3.62 2.35
22 -3.72 2.39
23 -3.82 2.43
24 -3.92 2.46
25 -4.02 2.50
26 -4.12 2.54
27 -4.21 2.58
28 -4.31 2.62
29 -4.40 2.66
30 -4.49 2.70
31 -4.58 2.74
32 -4.67 2.78
33 -4.76 2.82
34 -4.85 2.86
35 -4.94 2.90
36 -5.02 2.94
37 -5.11 2.97
38 -5.19 3.01
39 -5.28 3.05
40 -5.36 3.09
41 -5.45 3.13
42 -5.53 3.17
43 -5.61 3.21
44 -5.69 3.25
45 -5.77 3.29
46 -5.85 3.33
47 -5.93 3.37
48 -6.01 3.41
49 -6.09 3.44
50 -6.17 3.48
51 -6.25 3.52
52 -6.33 3.56
53 -6.40 3.60
54 -6.48 3.64
55 -6.56 3.68
56 -6.63 3.72
57 -6.71 3.76
58 -6.79 3.80
59 -6.86 3.84
60 -6.94 3.88
Pick Expected Stdev
1 1.37 2.02
2 0.68 2.05
3 0.25 2.07
4 -0.07 2.09
5 -0.34 2.11
6 -0.57 2.13
7 -0.77 2.15
8 -0.96 2.17
9 -1.13 2.19
10 -1.29 2.22
11 -1.44 2.24
12 -1.58 2.26
13 -1.72 2.28
14 -1.85 2.30
15 -1.98 2.32
16 -2.10 2.34
17 -2.22 2.37
18 -2.34 2.39
19 -2.45 2.41
20 -2.56 2.43
21 -2.67 2.45
22 -2.78 2.47
23 -2.88 2.49
24 -2.99 2.52
25 -3.09 2.54
26 -3.19 2.56
27 -3.29 2.58
28 -3.39 2.60
29 -3.48 2.62
30 -3.58 2.64
31 -3.67 2.66
32 -3.77 2.69
33 -3.86 2.71
34 -3.95 2.73
35 -4.04 2.75
36 -4.13 2.77
37 -4.22 2.79
38 -4.31 2.81
39 -4.40 2.84
40 -4.49 2.86
41 -4.57 2.88
42 -4.66 2.90
43 -4.75 2.92
44 -4.83 2.94
45 -4.92 2.96
46 -5.00 2.99
47 -5.09 3.01
48 -5.17 3.03
49 -5.25 3.05
50 -5.34 3.07
51 -5.42 3.09
52 -5.50 3.11
53 -5.58 3.13
54 -5.66 3.16
55 -5.75 3.18
56 -5.83 3.20
57 -5.91 3.22
58 -5.99 3.24
59 -6.07 3.26
60 -6.15 3.28
This should beat using simply -2 for rookies by quite a bit!
Re: 2012 predictions
Posted: Wed Dec 21, 2011 2:32 pm
by Mike G
Any minutes to go along with these rates?
It looks like a high or low draft pick improves about 0.9 in APM from yr1 to yr2.
Why not just add that difference to their rookie rate?
I see Evan has assigned mpg to players, which are minutes
per team game played (not mpg the player appears in), so a team sums to 242 mpg -- about the average, given overtimes.
That seems like a good convention.
( I did it by 100-minute units -- 16000 min/team -- but I can switch to integral mpg. )
Also, Evan: You don't list some players I've figured for major minutes: Krstic (Bos), Pachulia (Atl), Dante Cunningham and Reggie Williams (Cha), ... Are they not under contract?
I'm just looking at these pages:
http://sports.yahoo.com/nba/teams/cha/roster
They seem to update daily.
Re: 2012 predictions
Posted: Wed Dec 21, 2011 3:22 pm
by EvanZ
Yeah, that just seemed to me like the way most people think about playing time, and it's easy enough to look up without having to do any other calculations.
Re: 2012 predictions
Posted: Wed Dec 21, 2011 4:14 pm
by J.E.
EvanZ wrote:Here are my projections in a Google spreadsheet:
If you use RAPM numbers to make projections you need to multiply them with something between .5 and .8 first. (Normally, between .7 and .8 ist optimal, but because of the lockout something closer to .5 might be better). Taking the full values is definitely not optimal.
There will probably a small update of the latest '11 prior informed RAPM numbers tonight. Those new numbers*0.7 will be my "prediction" for the season.
I'll just use the code from the retrodiction contest to compare player metrics in their ability to "forecast" team differential given real minutes and projected ratings. I'll add some bits to compare the ability to predict "lineup differential", because to me, predicting team differential over the entire season feels like asking the weather man how many times it will rain next week, but not caring about whether it will rain Monday/Tuesday/etc.
Re: 2012 predictions
Posted: Wed Dec 21, 2011 4:29 pm
by EvanZ
J.E. wrote:EvanZ wrote:Here are my projections in a Google spreadsheet:
If you use RAPM numbers to make projections you need to multiply them with something between .5 and .8 first. (Normally, between .7 and .8 ist optimal, but because of the lockout something closer to .5 might be better). Taking the full values is definitely not optimal.
Why is this?
Re: 2012 predictions
Posted: Wed Dec 21, 2011 4:30 pm
by DSMok1
Regression to the mean, I would presume.
Re: 2012 predictions
Posted: Wed Dec 21, 2011 4:53 pm
by Kevin Pelton
Here are my current minute projections:
(Haven't used Google Docs publicly, so let me know if that shares correctly.)
Re: 2012 predictions
Posted: Wed Dec 21, 2011 6:20 pm
by DSMok1
Kevin Pelton wrote:Here are my current minute projections:
(Haven't used Google Docs publicly, so let me know if that shares correctly.)
That works fine, Kevin, thanks! What sort of methodology do you use to generate those?
Re: 2012 predictions
Posted: Wed Dec 21, 2011 6:49 pm
by EvanZ
Interestingly, the regression of Jerry's RAPM onto my 2-yr ezPM gives the following:
ezPM = 0.68*RAPM -0.06 (R^2 = 0.45)
So, I'll probably use that 0.68 as my RAPM multiplier.
Re: 2012 predictions
Posted: Wed Dec 21, 2011 7:20 pm
by Kevin Pelton
Games played is based on games missed the previous two years, plus an average of five games missed per player during the shortened season. The minutes are just my guesses.
Re: 2012 predictions
Posted: Wed Dec 21, 2011 7:26 pm
by EvanZ
Here are my corrected blended predictions (using Jerry's updated RAPM):
Code: Select all
EAST
MIA 76.5% 51 15
BOS 65.1% 43 23
CHI 64.9% 43 23
ORL 64.0% 42 24
ATL 54.5% 36 30
PHI 53.5% 35 31
NYK 53.2% 35 31
IND 48.8% 32 34
MIL 47.9% 32 34
NJN 37.6% 25 41
CHA 36.0% 24 42
DET 34.2% 23 43
CLE 33.0% 22 44
TOR 32.5% 21 45
WAS 28.6% 19 47
WEST
OKC 64.2% 42 24
LAL 62.9% 42 24
DAL 62.7% 41 25
LAC 57.8% 38 28
SAS 56.7% 37 29
MEM 54.5% 36 30
POR 53.9% 36 30
DEN 53.7% 35 31
PHO 47.2% 31 35
HOU 45.2% 30 36
GSW 43.1% 28 38
UTA 39.2% 26 40
SAC 39.2% 26 40
NOH 38.7% 26 40
MIN 34.2% 23 43