NBA Team Rankings - April 21, 2012

World War I Tank

Here are the NBA Betting Market Team Rankings as of April 21, 2012. These rankings use the Vegas point spreads from recent games to derive an implied measure of team strength (Generic Points Favored, or GPF). By combining the point spread information with the betting over/unders, I can also decompose team strength into its offensive and defensive components (oGPF and dGPF). For more detail, see the Methodology page.

At this point in the season, it's hard to say exactly what these rankings are telling us. Are the Thunder and Spurs really that much better than the Heat and Bulls? How much are the point spreads affected by teams resting up for the playoffs? Are teams that are out of the playoffs "tanking" in the hopes of getting a better lottery pick in the draft? Or do they simply not try as hard at this point?

You could use the rankings below as indirect evidence of "tanking" (or rather that the betting market is expecting tanking). There are currently 11 teams eliminated from playoff contention. Not coincidentally, those 11 teams occupy the bottom 11 spots in these rankings. And if you look at the actual GPF's of those teams, there is a noticeable drop-off in strength. Such a result would be consistent with teams giving up once they are eliminated from playoff contention.

The Rankings (glossary below)

Rank	Team	LstWk	GPF	oGPF		dGPF		GOU		W-L		GWP
1	OKC	1	8.5	7.0	2	1.5	13	200	7	46-17	3	0.79
2	SAS	3	8.5	8.5	1	0.0	16	203	4	46-16	2	0.78
3	MIA	4	5.0	1.5	10	3.5	6	192	20	45-17	4	0.69
4	CHI	2	5.0	-2.5	21	7.5	1	185	30	47-16	1	0.68
5	MEM	7	4.5	-1.0	18	5.5	3	188	25	38-25	8	0.67
6	ATL	9	4.0	0.5	14	3.5	7	192	21	38-25	9	0.66
7	LAC	5	4.0	-0.5	16	4.5	5	190	24	39-24	7	0.64
8	UTA	18	3.5	3.5	7	0.0	18	198	9	33-30	15	0.63
9	DAL	8	3.0	0.5	13	2.5	9	193	18	36-28	12	0.61
10	IND	12	2.5	1.5	9	1.0	15	195	14	41-22	5	0.60
11	LAL	10	2.5	1.0	11	1.5	11	194	17	40-24	6	0.60
12	PHX	13	2.5	4.5	5	-2.0	20	201	6	33-30	14	0.60
13	BOS	6	2.5	-3.5	26	6.0	2	185	29	37-27	11	0.59
14	PHI	11	2.0	-3.0	23	5.0	4	187	27	32-30	17	0.58
15	NYK	15	2.0	0.5	12	1.5	14	194	16	33-30	16	0.58
16	HOU	14	2.0	2.0	8	0.0	17	196	11	32-31	18	0.57
17	DEN	17	2.0	6.0	4	-4.0	25	205	3	34-28	13	0.57
18	MIL	16	1.0	6.0	3	-5.0	28	206	2	29-33	19	0.53
19	ORL	19	-1.0	-2.5	22	1.5	12	190	23	36-26	10	0.47
20	NOH	26	-3.5	-5.5	28	2.0	8	187	28	20-43	27	0.37
21	POR	20	-4.0	-1.5	19	-2.5	21	196	12	28-35	20	0.36
22	TOR	23	-4.0	-6.0	29	2.0	10	187	26	22-41	24	0.35
23	SAC	21	-4.0	4.0	6	-8.0	30	206	1	20-43	28	0.35
24	DET	22	-4.5	-3.5	25	-1.0	19	192	19	23-40	22	0.34
25	MIN	24	-5.0	-0.5	17	-4.5	27	199	8	26-38	21	0.31
26	GSW	25	-6.0	0.5	15	-6.5	29	202	5	22-40	23	0.28
27	WAS	28	-6.0	-2.0	20	-4.0	24	197	10	16-46	29	0.28
28	NJN	27	-6.5	-3.0	24	-3.5	22	195	13	22-41	25	0.26
29	CLE	29	-9.0	-4.5	27	-4.5	26	194	15	21-41	26	0.20
30	CHA	30	-11.5	-7.5	30	-4.0	23	191	22	7-55	30	0.14

GLOSSARY

LstWk - The BTM ranking from last week.

GPF - Stands for "Generic Points Favored". It's what you would expect the team to be favored by against a league average opponent at a neutral site.

oGPF - Stands for "Offensive Generic Points Favored". The component of a team's total GPF attributable to its ability to score points (per game).

dGPF - Stands for "Defensive Generic Points Favored". The component of a team's total GPF attributable to its ability to prevent the other team from scoring points (per game).

GOU - Stands for "Generic Over/Under". It's what you would expect the betting over/under to be for the given team when playing a league average opponent.

W-L - The team's win/loss record (and win percentage rank)

GWP - Stands for "Generic Win Probability". I converted the GPF into a win probability using the following formula: 1/(1 + exp(-GPF/6.5)).

Additional Key Factors:

League Average Points Scored (APS): 97.0 points
Home Court Advantage (HCA): 3.25 points
Back to Back Penalty (B2B): -1.25 points (see here)

How to Use This Table to Build Point Spreads and Over/Unders

Point Spread (in favor of home team) = HCA + (B2B_home - B2B_away) + (GPF_home - GPF_away)
Over/Under = 2*APS + (oGPF_home + oGPF_away - dGPF_home - dGPF_away)