RAPM last season for recent acquisitions of some teams

[J.E.]

However, to simplify the conversation I will just say this: better prediction accuracy implies a more accurate estimate of player ability, on average. Certainly some players will be more wrong in the xRAPM estimates than the RAPM estimates, but a greater number will be more wrong in the RAPM estimates than the xRAPM estimates.

Exactly. Thanks for writing that up

[v-zero]

I see what you mean, however I think (though I don't know, I find it hard to believe that J.E. wouldn't have done this) that J.E. used box score data to fit offensive and defensive ability separately, so that the two could then be used for a split xRAPM.

EDIT: No problem J.E., I'm always bothered by the fixation on 'real' RAPM.

[nanawacin]

"diff" means difference between 2006 non prior informed real RAPM and 2006 xRAPM ("+" means player looks better in xRAPM, "-" better in real RAPM).

It's not coincidence that on average bigs look better defensively in xRAPM than in real RAPM, while small players worse. That's what always happens when someone tries to evaluate defensive value and uses box score. That's why xRAPM is crap on defense-offense splits level.

Code: Select all

2006 NPI	Defense per 100	rank	diff
Reggie Evans	-1,7	427	348
Jerome James	-1,6	417	306
Paul Pierce	-1,6	419	303
Dale Davis	-1,3	389	292
Chris Webber	-2	437	291
Donyell Marshall	-1,7	424	268
Antonio McDyess	-1,3	387	260
Malik Rose	-1,2	384	251
Loren Woods	-0,6	304	244
Tony Battie	-0,6	311	241
Calvin Booth	-1,1	367	239
Michael Ruffin	-0,9	351	236
Brian Skinner	-0,6	295	232
Mark Blount	-1,1	377	229
Troy Murphy	-1,8	431	229
Rashard Lewis	-2,9	452	226
Al Harrington	-1,1	366	225
Mehmet Okur	-1	359	222
Eddy Curry	-0,8	330	217
Ervin Johnson	-1,2	380	214
Eddie Griffin	-0,4	262	212
Jason Kidd	-0,5	282	208
Viktor Khryapa	-1,4	410	207
Joe Smith	-2	438	201
Kris Humphries	-1,1	374	199
Zaza Pachulia	-0,5	290	198
Bonzi Wells	-0,7	313	194
Bo Outlaw	-0,5	277	190
Vladimir Radmanovic	-1,3	399	190
Chris Bosh	-0,4	259	188
Lamond Murray	-1,8	429	182
Zeljko Rebraca	-1,2	385	174
Antawn Jamison	-1,3	386	173
Nene Hilario	-0,3	245	173
Chris Mihm	-0,4	260	172
Pape Sow	-1	360	170
Steve Francis	-1	363	170
Chris Andersen	-0,1	192	169
Al Jefferson	-0,8	319	168
Mikki Moore	-1,4	407	167
Josh Smith	-0,2	218	165
Larry Hughes	-1,5	413	165
Aaron McKie	-0,8	318	156
James Jones	-1,3	392	156
Raef LaFrentz	-0,3	247	156
Toni Kukoc	-1,6	421	152
Joel Przybilla	0,1	161	149
Ruben Patterson	-1,5	415	149
Morris Peterson	-1,9	433	148
Antonio Davis	-0,3	228	147
David West	-0,8	328	143
Brian Grant	-0,8	325	142
Darko Milicic	-0,3	231	142
Dwight Howard	0	174	142
Quentin Richardson	-0,6	308	140
Alan Henderson	-0,8	320	138
Dirk Nowitzki	-0,1	196	138
Chris Duhon	-1,1	368	137
John Thomas	-1	357	137
Michael Doleac	-0,5	286	137
Marvin Williams	-0,8	336	136
James Singleton	-1,5	412	134
Dikembe Mutombo	0,2	138	129
Nick Collison	-0,6	307	129
David Lee	-2,1	440	128
Scott Padgett	-0,3	250	124
Aaron Williams	-0,6	291	121
Nazr Mohammed	-0,2	223	121
Melvin Ely	-0,3	243	120
Jumaine Jones	-0,6	303	116
Andres Nocioni	-0,9	342	113
Kobe Bryant	-1,1	373	113
Caron Butler	-0,6	296	112
Darrell Armstrong	-0,8	327	112
Jon Barry	-1,7	426	112
Juwan Howard	-0,8	333	112
Andrew Bynum	-0,8	323	111
Eric Williams	-0,9	345	111
Zach Randolph	-0,4	276	107
P,J, Brown	0,1	166	102
Charlie Villanueva	-1,8	428	101
Mike Miller	-1,6	418	100
Jake Voskuhl	-0,1	199	99
James Posey	-0,1	200	99
Dahntay Jones	-1,3	388	97
Clifford Robinson	-0,3	230	95
Hakim Warrick	-1,1	370	95
Jamaal Magloire	0,3	129	94
Joe Johnson	-1,4	405	92
Kevin Ollie	-1,1	372	91
LeBron James	-0,1	202	90
Primoz Brezec	-0,9	353	90
Scot Pollard	0,2	145	88
Baron Davis	-0,4	257	86
Brian Scalabrine	-0,3	229	84
Anthony Carter	-0,8	324	81
Elton Brand	0,4	115	81
Othella Harrington	-0,3	246	79
Dan Gadzuric	0,3	123	78
John Salmons	-2,3	448	76
Kyle Korver	-1	358	76
Amare Stoudemire	-0,2	209	75
Matt Bonner	-2	439	75
Greg Ostertag	0,6	97	73
Shareef Abdur-Rahim	-0,3	251	72
Travis Outlaw	-0,3	252	71
Gilbert Arenas	-1,6	416	67
Rick Brunson	-0,7	316	66
Samaki Walker	-0,4	272	65
Bernard Robinson	-0,6	294	64
Kendrick Perkins	0,4	117	63
Shawn Marion	0,7	93	63
Josh Childress	-2,7	451	61
Emeka Okafor	0,3	126	60
Tim Thomas	-1,9	435	60
Johan Petro	-0,2	217	59
Esteban Batista	-0,2	214	57
Jermaine O'Neal	0,7	87	50
Devean George	0,1	157	47
Robert Horry	0,7	90	46
Alonzo Mourning	1,1	51	45
Gerald Wallace	0,9	66	45
Andris Biedrins	0,1	149	44
Carlos Boozer	-3,4	455	44
Trenton Hassell	-1	365	44
Linton Johnson	-0,2	219	43
Lonny Baxter	-0,2	220	43
Pau Gasol	0,7	89	43
Chris Paul	0	171	42
Tracy McGrady	0	186	42
Devin Harris	-0,7	315	41
Keith Van Horn	-2,1	443	41
Mike Dunleavy	0,1	165	41
Zydrunas Ilgauskas	0,8	80	41
Austin Croshere	-0,6	292	40
Kelvin Cato	0,9	68	39
Boniface N'Dong	-1,7	422	38
Bryon Russell	-0,1	191	38
Damien Wilkins	-1,7	423	38
Ha Seung-Jin	-0,8	331	37
Antoine Walker	-0,1	188	36
Jake Tsakalidis	0,4	116	36
Andrei Kirilenko	1,4	40	35
Marcus Camby	1,5	37	35
Mario Kasun	-0,8	335	34
Manu Ginobili	0,5	109	31
Mark Madsen	0,6	100	31
Jeff Foster	1,1	54	29
Brad Miller	0,9	64	28
Jason Maxiell	-2,1	442	28
Tony Allen	0,2	146	28
Linas Kleiza	-0,4	265	27
Danny Granger	0	172	25
Kenny Thomas	0,5	107	25
Luke Ridnour	-3,3	454	25
Travis Diener	-1,8	430	25
Hedo Turkoglu	-0,6	300	24
Jamal Sampson	0,1	159	23
Devin Green	-1,3	391	22
Moochie Norris	-0,6	306	22
Sean Marks	-0,6	310	22
Steven Hunter	0,9	70	22
Michael Olowokandi	1	62	20
Ronny Turiaf	-1,5	414	20
Darius Miles	0,6	95	18
Doug Christie	0,3	125	18
Kenyon Martin	0,9	69	18
Lamar Odom	1,1	56	18
Brevin Knight	0,7	82	17
Jamal Crawford	-3,1	453	17
Kevin Burleson	-0,3	238	16
Mateen Cleaves	-0,9	349	16
Matt Harpring	-0,9	350	16
Shaquille O'Neal	1,5	38	16
Stephon Marbury	-1,6	420	16
Theo Ratliff	2	20	16
Jackson Vroman	0,3	128	14
Nikoloz Tskitishvili	-0,9	352	14
Zarko Cabarkapa	-1,4	411	14
DeSagana Diop	1,9	21	13
Etan Thomas	1,1	53	13
Martell Webster	-2,1	444	13
Sean May	-0,1	205	13
Devin Brown	-2,2	446	12
Erick Dampier	1,7	27	10
Reece Gaines	-1	361	9
Tyson Chandler	1,8	25	9
Anderson Varejao	1,4	39	8
Carlos Delfino	-2	436	8
Tim Duncan	2,7	11	8
Stromile Swift	0,6	103	7
John Lucas	-0,6	302	6
Brendan Haywood	2,4	15	5
Kevin Garnett	2,2	18	5
Marcus Fizer	-0,6	305	5
Dan Dickau	-1,4	403	4
Luke Walton	-0,1	203	4
Peja Stojakovic	-1,3	396	4
Rasheed Wallace	1,9	23	4
Ray Allen	-1,3	397	4
Sergei Monia	-1,9	434	4
Will Bynum	-1,3	400	4
Antonio Daniels	-1,4	401	3
Jermaine Jackson	-1,2	382	3
Jonathan Bender	-0,5	283	3
Leandro Barbosa	-3,5	456	3
Maurice Taylor	-0,3	242	3
Mo Williams	-2,3	449	3
Steve Blake	-2,5	450	3
Chris Wilcox	0,3	122	2
DeShawn Stevenson	-2,1	441	2
Marcus Banks	-0,8	334	2
Ben Wallace	3,8	2	1
C,J, Miles	-0,9	344	1
Drew Gooden	1	61	0
Earl Boykins	-4,3	457	0
Fabricio Oberto	-1,1	369	-1
Pat Burke	-1,4	408	-1
Samuel Dalembert	2,5	13	-1
T,J, Ford	-0,1	207	-1
Andray Blatche	-0,9	340	-2
Sam Cassell	-0,8	338	-2
Adonal Foyle	3,1	4	-3
Mike James	-1,1	378	-3
Ronnie Price	-1	362	-3
Brent Barry	-0,1	190	-4
Jason Collins	2,9	7	-4
Joey Graham	-1,2	383	-6
Salim Stoudamire	-2,1	445	-6
Udonis Haslem	0,8	79	-6
Yao Ming	2,5	14	-6
Jalen Rose	-1,2	381	-7
John Edwards	-1,3	393	-7
Derek Anderson	-1,4	404	-8
Eddie Jones	1,2	48	-8
Jason Richardson	0	178	-8
Jeff McInnis	-2,3	447	-8
Eduardo Najera	0,7	85	-9
Lorenzen Wright	2,4	16	-10
Danny Fortson	0,1	154	-11
David Harrison	2,3	17	-11
Francisco Elson	1,5	36	-11
Josh Powell	-1,4	406	-11
Bobby Simmons	0,7	81	-12
Donta Smith	-0,5	280	-12
Rasho Nesterovic	3	6	-12
Shane Battier	3,8	3	-12
Zendon Hamilton	-0,6	312	-12
Bostjan Nachbar	-0,9	343	-15
Lawrence Roberts	-0,5	284	-15
Rafael Araujo	0,5	110	-15
Stephen Graham	-0,8	339	-15
Trevor Ariza	1,3	47	-15
Jarrett Jack	-1,7	425	-16
Shavlik Randolph	0,3	134	-16
Andre Iguodala	1,5	32	-17
Awvee Storey	-0,4	256	-17
Dorell Wright	-0,8	329	-17
Calbert Cheaney	-0,8	326	-18
Derek Fisher	0,2	137	-18
Ryan Gomes	-0,3	249	-18
Chris Kaman	1,8	24	-19
Francisco Garcia	-0,2	215	-20
Juan Dixon	-1,9	432	-20
Jose Calderon	-1,3	394	-22
Stephen Jackson	0,4	121	-22
Terence Morris	-0,5	287	-22
Pat Garrity	-1,4	409	-23
Michael Redd	-1,3	395	-24
Rafer Alston	0,4	118	-24
Greg Buckner	0,5	106	-25
Ike Diogu	-0,9	346	-25
Kurt Thomas	2,9	8	-25
Keith Bogans	0,1	162	-26
Kwame Brown	1,4	42	-26
Metta World Peace	4	1	-26
Speedy Claxton	0,3	135	-26
Marc Jackson	-1,1	376	-27
Andrew Bogut	1,7	26	-29
Jared Jeffries	2,5	12	-29
Jim Jackson	-0,2	216	-30
Jiri Welsch	-0,8	332	-30
Justin Reed	-1,1	371	-30
Brandon Bass	-0,4	258	-31
Deron Williams	-1,3	390	-32
Lee Nailon	-0,9	348	-32
Dijon Thompson	-0,6	297	-33
Luke Jackson	-1,1	375	-33
Grant Hill	0,2	139	-34
Kevin Martin	-0,4	264	-34
Alex Acker	-0,8	321	-35
Amir Johnson	-0,8	322	-35
Channing Frye	0	169	-35
Steve Nash	-0,4	273	-35
Yaroslav Korolev	-0,4	275	-35
Andre Barrett	-0,9	341	-36
Robert Whaley	-0,4	271	-36
Orien Greene	0,6	101	-37
Smush Parker	0,6	102	-37
Bruce Bowen	1,5	34	-39
Desmond Mason	0,1	156	-39
Luol Deng	1,3	44	-39
Marko Jaric	1,3	45	-39
Michael Bradley	-0,2	222	-39
Qyntel Woods	-0,2	224	-40
Shandon Anderson	0,4	120	-40
Adrian Griffin	0,9	63	-41
Brian Cardinal	0,9	65	-41
Robert Swift	1,1	57	-42
Donell Taylor	0	173	-43
Gary Payton	0	175	-43
Raja Bell	0	182	-43
Charlie Bell	-0,7	314	-45
Ryan Bowen	1,1	58	-45
Boris Diaw	3	5	-47
Chuck Hayes	1,6	29	-47
Chucky Atkins	-1,4	402	-47
Mike Sweetney	1,7	28	-47
Richard Jefferson	0,2	143	-48
Von Wafer	-0,4	274	-48
Earl Barron	-0,6	298	-49
Gerald Fitch	-0,6	299	-49
Jarron Collins	2,7	10	-49
Randy Holcomb	-0,4	270	-49
Sharrod Ford	-0,7	317	-49
Matt Walsh	-0,5	285	-50
Matt Carroll	-0,4	266	-51
Josh Howard	1,4	41	-54
Dwyane Wade	1,5	35	-55
Vince Carter	1,6	31	-55
Alvin Williams	-0,4	255	-56
Earl Watson	0,8	74	-56
Tyronn Lue	-1,3	398	-56
Eric Snow	2,8	9	-58
Rasual Butler	0	183	-58
Delonte West	0,4	113	-59
Andre Owens	-0,2	210	-60
Cuttino Mobley	1	60	-61
Eddie Gill	-0,3	232	-61
Ira Newble	0,1	158	-61
Josh Davis	-0,3	236	-61
Randy Livingston	-0,2	225	-61
Darius Songaila	-0,1	193	-62
Darrick Martin	-0,1	194	-62
Didier Ilunga-Mbenga	-0,1	195	-63
Raymond Felton	0	185	-64
Jackie Butler	0,9	67	-65
Andre Miller	1,3	43	-66
Derrick Zimmerman	-0,5	279	-66
Willie Green	-0,5	289	-66
Kirk Hinrich	1,1	55	-67
Deng Gai	-0,4	261	-68
Julius Hodge	-0,4	263	-68
Damon Jones	-1	355	-70
Noel Felix	-0,4	269	-70
Allen Iverson	-0,4	254	-71
Ronald Dupree	-0,3	248	-72
Martynas Andriuskevicius	-0,3	241	-75
Louis Williams	-0,3	239	-76
Nenad Krstic	1,9	22	-76
Troy Hudson	-1,1	379	-77
J,R, Smith	-0,9	347	-79
Sebastian Telfair	-0,9	354	-79
Brian Cook	0,7	83	-81
Stacey Augmon	1,1	59	-81
Jason Kapono	-1	356	-82
Melvin Sanders	-0,2	221	-82
Milt Palacio	0,2	141	-83
Tony Delk	-1	364	-86
Tayshaun Prince	1,6	30	-87
Jamaal Tinsley	0,7	86	-88
Shaun Livingston	0,7	92	-88
Quinton Ross	2	19	-89
Anthony Johnson	0,8	73	-90
Eric Piatkowski	0,3	127	-90
Luke Schenscher	0,3	131	-92
Michael Finley	-0,3	244	-92
Jason Hart	-0,1	201	-94
Pavel Podkolzin	0,1	167	-95
Fred Jones	0,6	96	-101
Ime Udoka	0	176	-101
Ronald Murray	-0,6	309	-101
Bracey Wright	0,4	112	-102
Chris Taft	0,1	152	-102
Corey Maggette	1,1	52	-102
DerMarr Johnson	0,1	155	-102
Aaron Miles	0,1	148	-103
Rawle Marshall	0	184	-103
Mike Bibby	-0,4	268	-106
Richie Frahm	-0,8	337	-106
Walter McCarty	0,6	104	-106
Malik Allen	0,6	99	-107
Anthony Grundy	0,2	136	-108
Daniel Ewing	-0,5	278	-108
Sasha Vujacic	0,4	119	-108
Luther Head	1,2	49	-110
Lindsey Hunter	0,8	77	-112
Keith McLeod	-0,3	237	-113
Vin Baker	-0,2	226	-115
Dwayne Jones	0,4	114	-119
James Thomas	0,1	160	-119
Mickael Pietrus	0,1	164	-119
Anthony Roberson	0,1	150	-121
Arvydas Macijauskas	0,1	151	-121
Charles Smith	0,7	84	-121
David Wesley	0,3	124	-121
Eddie Basden	0,8	75	-121
Carmelo Anthony	0	168	-122
Laron Profit	0,8	76	-122
Maciej Lampe	-0,3	240	-123
Maurice Evans	-0,4	267	-124
Anfernee Hardaway	0,4	111	-131
Vitaly Potapenko	-0,5	288	-135
Corliss Williamson	0,6	94	-138
Howard Eisley	-0,6	301	-139
Marquis Daniels	0,1	163	-139
Rashad McCants	-0,1	204	-147
Stanislav Medvedenko	-0,1	206	-147
Matt Barnes	1,2	50	-151
Gordan Giricek	-0,5	281	-154
Beno Udrih	-0,6	293	-155
Antonio Burks	-0,3	227	-156
Billy Thomas	-0,2	212	-156
Zoran Planinic	0,9	72	-156
Nate Robinson	0	180	-157
Chauncey Billups	0	170	-158
Voshon Lenard	-0,1	208	-159
Ricky Davis	0,2	144	-162
Monta Ellis	0,2	142	-163
Alan Anderson	-0,4	253	-167
Anthony Goldwire	-0,2	211	-167
Keyon Dooling	0,7	88	-171
Jerry Stackhouse	-0,3	235	-172
Mike Wilks	0,3	132	-172
Wayne Simien	0,2	147	-176
Jarvis Hayes	-0,3	234	-179
Royal Ivey	0,8	78	-187
Jacque Vaughn	-0,1	198	-189
Wally Szczerbiak	0	187	-195
Gerald Green	-0,1	197	-209
Carlos Arroyo	-0,2	213	-211
Eddie House	-0,3	233	-211
Bobby Jackson	1,5	33	-220
Ben Gordon	0,5	105	-221
Jason Terry	0,2	140	-221
Sarunas Jasikevicius	1,3	46	-222
Jameer Nelson	0,3	130	-230
Antoine Wright	-0,1	189	-232
Jason Williams	0	179	-236
Jannero Pargo	0	177	-260
Nick Van Exel	0	181	-264
Kirk Snyder	0,5	108	-265
Damon Stoudamire	0,1	153	-289
Richard Hamilton	0,3	133	-294
Sasha Pavlovic	0,7	91	-304
Tony Parker	0,9	71	-305
Kareem Rush	0,6	98	-320

[v-zero]

The alternative hypothesis is that bigs on average are better defensive players than the smaller guys, which they are. Normal RAPM doesn't know who is or isn't big, so it can't introduce this bias... Tell it somehow, and it would.

[nanawacin]

But only because someone is bigger doesn't mean he's better on defense. That's (height factor or box score bias or both) why guys like McGee or Al Jefferson looks better in fake RAPM than in real DRAPM and that's why xRAPM doesn't tell the truth about defensive value. And that's also why so many people value real RAPM over fake RAPM - better description of individual impact on D.

[v-zero]

Just because somebody's DRAPM is good doesn't mean he's good on D either. This is all estimation.

[nanawacin]

Yes, but many people are using RAPM that way. But I guess it's bad idea, because xRAPM explanatory power is really bad, right? RAPM should be used only for predictions?

[v-zero]

What do you mean by explanatory power? (This isn't a trick question, I just don't get what people think makes a big difference between 'explanatory' and 'predictive' in this instance.)

[nanawacin]

What do you mean by explanatory power? (This isn't a trick question, I just don't get what people think makes a big difference between 'explanatory' and 'predictive' in this instance.)

http://sportskeptic.wordpress.com/2012/ ... -happened/
(parts 2 and 3 also are interesting)

[v-zero]

Ah, yes, I have read those. The first part mentions the fact that 'explaining' in that way is essentially meaningless - any metric which sums to in season point differential will do extremely well in such a test.

[AcrossTheCourt]

Just to stick my nose in here a minute, predictive generally implies the future while explanatory implies the past.

[BasketballJedi]

EDIT: No problem J.E., I'm always bothered by the fixation on 'real' RAPM.

That can be true of *any* metric of course, depending on the person using it. There's always the temptation to treat one's 'favorite' or 'go-to' stat as a holy grail summary of player ability.

As for the bickering over xRAPM overrating certain bigs on defense, can we act like 'real' ( ) RAPM didn't have glaring issues of its own? Like making Steve Nash a better defender than most people (and I mean both the analytic and the layman observer) would rate him out to be? Quirks happen. The point is to get it right more often than not, and that's the advantage xRAPM has over its predecessor.

[nanawacin]

EDIT: No problem J.E., I'm always bothered by the fixation on 'real' RAPM.

That can be true of *any* metric of course, depending on the person using it. There's always the temptation to treat one's 'favorite' or 'go-to' stat as a holy grail summary of player ability.

As for the bickering over xRAPM overrating certain bigs on defense, can we act like 'real' ( ) RAPM didn't have glaring issues of its own? Like making Steve Nash a better defender than most people (and I mean both the analytic and the layman observer) would rate him out to be? Quirks happen. The point is to get it right more often than not, and that's the advantage xRAPM has over its predecessor.

But the point is that xRAPM isn't "right more often than not" - xRAPM overrates ALL bigs on defense just because they are bigs...

[v-zero]

But the point is that xRAPM isn't "right more often than not" - xRAPM overrates ALL bigs on defense just because they are bigs...

No, it's nearer to right more often than RAPM, and it does not overrate all bigs, but does have a systematic bias towards bigs being good on D, which isn't really an issue because there are more good defensive bigs than smalls in the NBA, and in basketball in general, for obvious reasons.

[nanawacin]

But the point is that xRAPM isn't "right more often than not" - xRAPM overrates ALL bigs on defense just because they are bigs...

No, it's nearer to right more often than RAPM,

Any proof? (only defense on individual level, not overall results)

and it does not overrate all bigs, but does have a systematic bias towards bigs being good on D, which isn't really an issue

That's BIG issue, because xDRAPM doesn't tell the truth about players defensive value.