Introducing Simple Shot Quality Model (SSQM) v2.0

Sravan February 18, 2024 [NBA] #Shooting #Shot Quality #SSQM

My second attempt at creating a shot quality model using publicly available NBA data. First attempt is here.

Introduction

As I noted in my previous blog, only shot location is not a holistic way of looking at shot quality and there should be other factors like shot type, defender distance, touch time, dribble etc. which need to be incorporated in the model. So this model, which I named SSQM v2.0 is an attempt to include those factors.

Methodology

Approach: Using Shot Tracking Data

SSQM v2.0 is heavily inspired by AutomaticNBA's shot quality model, which uses NBA shot tracking data to categorize shots by defender distance and shot type. I'm extending AutomaticNBA's model by adding touch time as an additional category. The categories in my model are:

Shot Type: Catch and Shoot, Pullups, Less Than 10 ft
Defender Distance: 0-2 Feet - Very Tight, 2-4 Feet - Tight, 4-6 Feet - Open, 6+ Feet - Wide Open
Touch Time: Touch < 2 Seconds, Touch 2-6 Seconds, Touch 6+ Seconds

Approach: Binning Shots

There are 3 shot types, 4 defender distance and 3 touch times for the shots tracked by NBA. So we have $3\times 4\times 3=36$ shot bins. The actual number is 28 categories since Catch and shoot shots don't have touch times greater than 2 seconds. So, we have to bin the shots into 28 different categories, for each player and overall for the league. Following the same approach as SSQM v1.0, I use league average for each bin as the expected FG% or xFG in my model. Then determine the shot quality metrics based on the xFG for each bin.
The method to calculate the shot quality metrics can be found here.

Results

Now that I have a Shot Quality Model based on defender distance, shot type, and touch time, I ran it for the 2023-24 NBA season to generate the shot quality metrics for all players. An issue here is that there are players who have not attempted many shots but made most of them. We need to filter those players out, which can be accomplished by removing players who have scored less than 100 points.

Best Shot Makers

Here are the best shot makers in the league i.e. the players having the highest Shot Making values:

	Player	Team	FGM	FGA	PTS	xPTS	eFG	xeFG	Shot_Making	Points_Added
1	Garrison Mathews	Atlanta Hawks	45	99	130	104.39	0.657	0.527	0.259	25.6
2	Kevin Durant	Phoenix Suns	491	911	1067	856.66	0.596	0.479	0.235	214.1
3	Jalen Smith	Indiana Pacers	159	251	356	301.35	0.721	0.61	0.221	55.5
4	Matt Ryan	New Orleans Pelicans	38	85	108	90.18	0.635	0.53	0.21	17.8
5	Nicolas Batum	Philadelphia 76ers	70	135	184	155.98	0.681	0.578	0.208	28.1
6	Amir Coffey	LA Clippers	90	161	215	181.86	0.668	0.565	0.206	33.2
7	Sam Merrill	Cleveland Cavaliers	100	228	287	240.32	0.629	0.527	0.205	46.7
8	Malik Beasley	Milwaukee Bucks	222	474	591	503.12	0.629	0.535	0.187	88.6
9	Dante Exum	Dallas Mavericks	116	203	263	227.43	0.648	0.56	0.175	35.5
10	Aaron Wiggins	Oklahoma City Thunder	123	211	284	247.71	0.683	0.595	0.174	36.7

Most of the players in this list are movement three point shooters. An interesting observation is that 6 players on this list are common to both SSQM v1.0 and SSQM v2.0. So, best shooters show up regardless of the shot quality model used.

Worst Shot Makers

Here are the worst shot makers in the league i.e. the players having the lowest Shot Making values:

	Player	Team	FGM	FGA	PTS	xPTS	eFG	xeFG	Shot_Making	Points_Added
1	Xavier Tillman	Boston Celtics	87	210	186	251.46	0.443	0.599	-0.312	-65.5
2	JT Thor	Charlotte Hornets	51	139	119	153.99	0.434	0.562	-0.255	-35.4
3	Josh Okogie	Phoenix Suns	76	181	170	212.08	0.475	0.592	-0.235	-42.5
4	Chris Duarte	Sacramento Kings	47	129	114	142.15	0.445	0.555	-0.22	-28.4
5	Isaiah Livers	Washington Wizards	40	114	102	126.59	0.447	0.555	-0.216	-24.6
6	Scoot Henderson	Portland Trail Blazers	190	506	426	530.18	0.426	0.53	-0.208	-105.2
7	Mike Muscala	Detroit Pistons	48	133	123	149.01	0.466	0.564	-0.197	-26.2
8	David Roddy	Phoenix Suns	153	379	354	428.67	0.467	0.566	-0.197	-74.7
9	Jaylin Williams	Oklahoma City Thunder	57	149	144	172.51	0.49	0.587	-0.194	-28.9
10	Cam Reddish	Los Angeles Lakers	80	199	191	227.41	0.48	0.571	-0.183	-36.4

9 players on this list are common to both SSQM v1.0 and SSQM v2.0, but in a different order. Most of these players are end of bench players, except Scoot Henderson who is having a rough start to his NBA career.

Most Points Added: Best Volume Shot Makers

Just looking at Shot Making doesn't tell the whole story of best shot makers in the league. The Shot Making value is actualized only if the players are taking lots of the shots. So the best shot makers in the league are who make lots of shots at high volume. To differentiate these players (who are all stars) from best players in Shot Making metric, I call them Volume Shot Makers. These players are players who have the highest Points Added Metric:

	Player	Team	FGM	FGA	PTS	xPTS	eFG	xeFG	Shot_Making	Points_Added
1	Kevin Durant	Phoenix Suns	491	911	1067	856.66	0.596	0.479	0.235	214.1
2	Luka Doncic	Dallas Mavericks	542	1101	1254	1102.56	0.573	0.503	0.138	151.9
3	Shai Gilgeous-Alexander	Oklahoma City Thunder	580	1063	1225	1084.6	0.576	0.51	0.132	140.3
4	Giannis Antetokounmpo	Milwaukee Bucks	626	1018	1273	1134.36	0.628	0.559	0.137	139.5
5	Stephen Curry	Golden State Warriors	442	958	1126	989.61	0.591	0.519	0.143	137
6	Devin Booker	Phoenix Suns	420	840	935	812.23	0.559	0.486	0.147	123.5
7	Kawhi Leonard	LA Clippers	425	811	946	823.89	0.589	0.513	0.152	123.3
8	Nikola Jokic	Denver Nuggets	527	918	1076	972.83	0.61	0.551	0.117	107.4
9	Domantas Sabonis	Sacramento Kings	437	703	896	795.82	0.645	0.573	0.144	101.2
10	Brandon Ingram	New Orleans Pelicans	406	823	881	784.68	0.538	0.479	0.118	97.1

Similar to the previous list, 9 players on this list are common to both SSQM v1.0 and SSQM v2.0, but in a different order. All os these players are considered either stars or super-stars in the NBA. Giannis rank is higher here compared to SSQM v1.0 because the shot difficulty of his 2 pt shots which have a close defender distance and high touch time, gives him a lower xeFG on his shots and thus higher Shot Making.

Most Points Removed: Worst Volume Shot Makers

Now let's look at the worst volume shot makers, these are players with the lowest Points Added metric:

	Player	Team	FGM	FGA	PTS	xPTS	eFG	xeFG	Shot_Making	Points_Added
1	Scoot Henderson	Portland Trail Blazers	190	506	426	530.18	0.426	0.53	-0.208	-105.2
2	Nikola Vucevic	Chicago Bulls	369	786	794	895.3	0.509	0.574	-0.13	-102.2
3	Jordan Poole	Washington Wizards	292	729	685	773.44	0.472	0.533	-0.122	-88.9
4	Jalen Green	Houston Rockets	335	814	763	850.74	0.472	0.526	-0.108	-87.9
5	Saddiq Bey	Atlanta Hawks	244	576	583	665.95	0.507	0.579	-0.144	-82.9
6	Josh Giddey	Oklahoma City Thunder	246	551	537	618.71	0.494	0.57	-0.15	-82.6
7	Jeremy Sochan	San Antonio Spurs	245	555	532	611.38	0.485	0.557	-0.145	-80.5
8	Jordan Clarkson	Utah Jazz	282	680	642	716.57	0.473	0.528	-0.11	-74.8
9	David Roddy	Phoenix Suns	153	379	354	428.67	0.467	0.566	-0.197	-74.7
10	Ausar Thompson	Detroit Pistons	197	406	407	480.93	0.501	0.592	-0.182	-73.9

7 players on this list are common to both SSQM v1.0 and SSQM v2.0, but in a different order. Rookies here include Scoot and Ausar. Ausar come into the league as a bad shooter and need to improve his shooting to get more playing time. I'm a huge believer in his potential. Finally, Nikola Vucevic is having a horrible offensive season, and fits the criterion of aging centers which I discussed in the SSQM v1.0 blog.

Conclusions

I've developed a simple shot quality model SSQM v2.0 based on publicly available shooting data. The model is based purely on shot type, defender distance, and touch time. Then we can sort the players by the shot quality metrics like Shot Making and Points Added to find best and worst shot makers and volume shot makers.

Thank you for reading, and any feedback is appreciated. You can reach me on Twitter at @SravanNBA.