Spurs vs. Clippers: Study Hall - fun with advanced stats

The inspiration (and name) for "Study Hall" is a series of posts that the awesome Bill Connelly over at our sister blog Rock M Nation does for MU basketball games. I've enjoyed his posts for a couple years now and am now shamelessly copying him. Many of the metrics are different, but the spirit is the same. I hope PtR readers enjoy these as much as I enjoy Bill's work.

Interactive game flow chart

Spurs 125, Clippers 118

The Spurs offense fired on all cylinders in Tony Parker's return, scoring a season high 72 (!) first half points and a season-best 72% eFG as they torched the Clippers on their way to 125 total points.  They needed all of them, since the Clippers did all the little things well and were very efficient themselves, saddling the Spurs with a very questionable Defensive Rating of 120.7.

Four Factors (def.)

	Spurs	Clippers
Shooting (eFG%)	72%	56%
Ball Handling (TO%)	12%	10%
Off Rebounding (OR%)	7%	26%
Shooting FTs (FT Rate)	29%	34%

The Four Factors are a measure developed years ago by Dean Oliver to reflect the statistical categories that have the biggest impact on team victories. To put it in simple terms, a team which has the edge on a majority of the factors probably won the game. The Clippers dominated the boards, got to the line a lot and turned the ball over on just 10% of their possessions, besting the Spurs in three of the four factors. But when you shoot 72% eFG, nothing else matters all that much.

Team Stats (Definitions at bottom of post)

	Spurs	Clippers
Pace (No. of Possessions)	96.7
Points Per Possession (PPP)	1.29	1.22
Points Per Shot (PPS)	1.62	1.37
2-PT FG%	66.7%	53.2%
3-PT FG%	56.5%	41.7%
FT%	63.6%	75.9%
True Shooting %	72.1%	59.7%
	Spurs	Clippers
Uncontested FGA / Poss.	34.1%	27.9%
Offensive Rating	130.6	120.7
Defensive Rating	120.7	130.6
Net Rating	9.9	-9.9
	Spurs	Clippers
Assists	37	23
Steals	6	10
Turnovers	11	10
Ball Control Index (BCI) (Assists + Steals) / TO	3.91	3.30
	Spurs	Clippers
Expected Offensive Rebounds	6.8	10.5
Offensive Rebounds	2	11
Difference	-4.8	0

The Spurs racked up a season high 37 assists on the game, shot 72% True Shooting, scored 1.29 points per possession and an absolutely outrageous 1.66 points per shot. It truly was an offensive clinic. The Clippers were also incredibly efficient, keeping the Spurs off the offensive boards (not that there were many available), taking excellent care of the ball and scoring a robust 1.22 points per possession themselves.

It would be easy to assume that the Spurs played terrible defense in allowing their opponent to post a 120.7 Offensive Rating, but they allowed only an uncontested field goal on just 27.9% of Clippers possessions, a very low mark indeed. It should be noted that uncontested field goal attempts are defined as when a defender is within 4 feet of the shooter, and longer shots, especially 3s tend to be uncontested.  Teams which pound the ball inside will have fewer uncontested field goal attempts than teams which jack up 3s all day long, but you can still get a feel for how effectively a team generates good looks (and how effectively a defense prevents them) by measuring how many uncontested looks they get.  

For instance, last season the Spurs were one of the top teams in Uncontested FGA/Possession offensively, while allowing one of the lowest rates of uncontested looks on defense. And if my memory serves me, that season ended pretty well for the Silver and Black.

Player stats (Definitions at bottom of post)

Player	AdjGS	GmSc/Min	Line
Boris Diaw	22.1	0.88	25 Min, 23 Pts (9-11 FG, 2-3 3PT, 3-8 FT,) 6 Reb (1 Off), 3 Ast, 3 PF
Tony Parker	20.4	0.60	33 Min, 26 Pts (11-18 FG, 1-2 3PT, 3-4 FT,) , 4 Ast, 2 Stl, 3 TO, 2 PF
Manu Ginobili	20.3	0.74	27 Min, 19 Pts (7-11 FG, 2-5 3PT, 3-4 FT,) 2 Reb (0 Off), 10 Ast, 3 TO,
Tim Duncan	19.4	0.56	34 Min, 21 Pts (9-16 FG, 3-4 FT,) 12 Reb (0 Off), 1 Ast, 2 Stl, 1 TO, 2 PF
Danny Green	14.2	0.49	29 Min, 11 Pts (3-5 FG, 3-5 3PT, 2-2 FT,) 1 Reb (0 Off), 5 Ast, 1 Blk, 1 Stl, 1 TO, 1 PF
Marco Belinelli	11.7	0.41	28 Min, 9 Pts (3-4 FG, 3-4 3PT, ) 3 Reb (0 Off), 5 Ast, 3 PF
Cory Joseph	7.1	0.40	17 Min, 3 Pts (1-1 FG, 1-1 3PT, ) 1 Reb (0 Off), 3 Ast, 1 Blk, 1 Stl, 1 PF
Tiago Splitter	6.2	0.34	18 Min, 6 Pts (3-4 FG, ) 2 Reb (1 Off), 4 Ast, 1 TO, 4 PF
Kyle Anderson	4.7	0.47	9 Min, 5 Pts (2-4 FG, 1-2 3PT, ) 3 Reb (0 Off), 1 Ast, 1 PF
Matt Bonner	1.1	0.34	3 Min, 2 Pts (1-2 FG, 0-1 3PT, ) ,
Jeff Ayres	0.7	0.23	2 Min, 0 Pts 2 Reb (0 Off),
Austin Daye	0.0	0.00	0 Min, 0 Pts ,
Aron Baynes	-2.8	-0.30	9 Min, 0 Pts 1 Reb (0 Off), 1 Ast, 2 TO, 2 PF

Player	Usage%	Floor%	Plus Minus
Boris Diaw	27%	72%	8
Tony Parker	35%	53%	-13
Manu Ginobili	27%	61%	15
Tim Duncan	27%	52%	10
Danny Green	12%	66%	0
Marco Belinelli	7%	81%	4
Cory Joseph	3%	100%	23
Tiago Splitter	15%	66%	2
Kyle Anderson	20%	50%	-7
Matt Bonner	33%	44%	-3
Aron Baynes	15%	11%	-1

Game Score is a per-game metric similar to PER which tries to quantify a player's contributions across all stats according to a formula which rewards players who are more efficient and fill the whole stat sheet. Adjusted Game Score takes players' Game Scores and redistributes the points their team actually scored in the game. I like it on a per-game basis because it's pretty intuitive and gives you a quick sense of how valuable a player's non-scoring contributions were.

For instance, a player who scores 32 points on 41 shot attempts while turning the ball over 5 times and dishing out just 4 assists will have a rather low Adjusted Game Score despite the point total. On the other hand, a player who scores efficiently and racks up blocks, assists and steals will be richly rewarded.

Most of you are already familiar with Plus Minus, but a couple of interesting stats to note here are Usage Rate and Floor percentage.  Usage Rate tells you roughly what percentage of a team's possessions a player "consumes" while on the floor, whether it be by shooting, turning the ball over or assisting a teammate.  Floor percentage tells you "when a player does consume a possession, what are the odds the team scores at least 1 point?"  

Typically, a player with a really high Floor% (the team usually scores when the player uses the possession) will have a low Usage Rate (they don't consume many possessions), since it's much easier to be effective when you aren't the go-to option on offense.  Case in point: Corey Joseph's 100% Floor rate (wow!) went with a hilariously low 3% Usage Rate. Efficient! It is uncommon to see high Usage Rates (> 30%) coupled with high Floor percentages.  When you do, that player had a special game.  (Or they didn't play very many minutes)

Tonight the Spurs brought an incredibly balanced attack, with 6 players in double digit AdjGS, headlined by a fantastic (and rather overdue) performance from Boris Diaw, who scored 23 points, his highest scoring game in a Spurs jersey.  Tony Parker remained reasonably efficient while maintaining a high usage rate, and Manu Ginobili poured in 10 assists, including one of the sweetest no-look over-the-shoulder dimes that you will ever see to set up a Danny Green corner three which just about finished the Clippers off.

Tim Duncan continues to beat Father Time over the head with a lead pipe, tossing in 21 pts and 12 boards for yet another double double as he passed Reggie Miller at number 17 on the all-time NBA scoring list.  (Duncan posted an other-worldly 38.7 AdjGS in Friday's heartbreaking loss to the Trail Blazers)

Spurs Index: 115.9 (def.)

Factor	Value	Score
Passing (AST%)	75.5%	42.6
Shooting (eFG%)	72.1%	26.9
Defensive Rebounding (DReb%)	73.8%	14.5
Defense (DefRtg)	120.7	12.4
Uncontested FGA/Poss allowed	27.9%	19.6
Total	115.9

The Spurs Index is a five-part composite metric which attempts to quantify just how "Spursy" a particular game was.  You can read the particulars of how it's calculated below, but the important thing to know is that an average "Spursy" game has a Spurs index of 100. Tonight, the Spurs made up for a poor Defensive rating by netting assists on 75.5% of their made field goals, shooting 72% eFG, and (paradoxically) limiting open looks for the Clips.  The result: a very robust SI of 115.9.  Pop will be pleased when he is informed of this, I'm sure.

I'd love to hear everyone's thoughts on the new segment, including any questions you might have about any of the metrics, those you find awesome and those you find useless. I promise it will be easier to process these once you've seen a few more Study Halls and begin to get a feel for what to expect. So if your head's spinning right now, hang in there!

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Definitions (with major credit to Bill Connelly over at our sister blog Rock M Nation)

eFG%: Effective Field Goal percentage. (via) Effective Field Goal Percentage; the formula is (FG + 0.5 * 3P) / FGA. This statistic adjusts for the fact that a 3-point field goal is worth one more point than a 2-point field goal. For example, suppose Player A goes 4 for 10 with 2 threes, while Player B goes 5 for 10 with 0 threes. Each player would have 10 points from field goals, and thus would have the same effective field goal percentage (50%).

AdjGS: a take-off of the Game Score metric (definition here) accepted by a lot of basketball stat nerds. It takes points, assists, rebounds (offensive & defensive), steals, blocks, turnovers and fouls into account to determine an individual's "score" for a given game. The "adjustment" in Adjusted Game Score is simply matching the total game scores to the total points scored in the game, thereby redistributing the game's points scored to those who had the biggest impact on the game itself, instead of just how many balls a player put through a basket.

Usage%: This "estimates the % of team possessions a player consumes while on the floor" (via). The usage of those possessions is determined via a formula using field goal and free throw attempts, offensive rebounds, assists and turnovers. The higher the number, the more prevalent a player is (good or bad) in a team's offensive outcome.

Floor%: Via Basketball-Reference.com: Floor % answers the question, "when Player X uses a possession, what is the probability that his team scores at least 1 point?". The higher the Floor%, the more frequently the team probably scores when the given player is involved.

Offensive Rating (offRtg): Points per 100 possessions.

Defensive Rating (defRtg): Points allowed per 100 possessions.

Spurs Index: The Spurs Index © is a just-for-fun formula that attempts to quantify just how "Spursy" a particular game is, based off averages for the 2013-2014 regular season. A perfectly average game would have a Spurs Index of 100. The formula consists of four factors which the Spurs are known for and lead or nearly lead the league in: Shooting (effective Field Goal %), Passing (Assist percentage), Defensive Rebounding Rate, and Defensive Rating. These metrics are weighted as follows:

Factor	Weight	Average
Passing (AST%)	35%	62.1%
Shooting (eFG%)	20%	53.7%
Defensive Rebounding (DReb%)	15%	76.4%
Defense (DefRtg)	15%	100.1
Uncontested FGA/Poss allowed	15%	36.5%

The values for each metric are determined based on how a particular game's performance compares to the Spurs 2013-2014 regular season average for that metric. For instance, the average effective Field Goal percentage for 2013-2014 was 53.7%. So if the Spurs shot 60% in a given game, the score for eFG% would be calculated by: (0.6 / 0.537) * 20, which would yield a "score" for that factor of 22.3.