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1. 1 Example Math Projects in Basketball Dean Oliver
Author, Basketball on Paper
Consultant to the Seattle Supersonics
Math in Sports Symposium
Seattle, WA
May 13, 2006 There were a lot of things I could talk about in a second talk.
Playing up or down to opponents
Analysis of college players
Chance of winning the game at a given time/score
Roboscout applying math to interpret what scouts do
The process of optimizing a team through numbers
Ultimately these are long projects, the kind of project I dont see my 13 year old doing for quite some time.
So I wanted to illustrate some of the more basic things, some algebra that helps just work with data.
These are skills that I dont necessarily see out of some college kids who have come to work for me.There were a lot of things I could talk about in a second talk.
Playing up or down to opponents
Analysis of college players
Chance of winning the game at a given time/score
Roboscout applying math to interpret what scouts do
The process of optimizing a team through numbers
Ultimately these are long projects, the kind of project I dont see my 13 year old doing for quite some time.
So I wanted to illustrate some of the more basic things, some algebra that helps just work with data.
These are skills that I dont necessarily see out of some college kids who have come to work for me.
2. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 2
3. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 3 Where to Get Data Newspaper
Books
Sporting News, NBA Guide, NBA Register
Total Basketball
Internet
Dougstats.com
NBA.com
Basketball-Reference.com
82games.com
Ask me
4. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 4 What Data Look Like Who?
Player or player type
Ref
Team
Franchise
League
What?
Traditional stats
Calculated stats
Collect-your-own stats
Physical attributes
Financial data
Team playing stats are interrelated!
Need team stats!Team playing stats are interrelated!
Need team stats!
5. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 5 Analysis Come up with questions
Who is better? (Right now? Individual production or help team to win by doing role?)
Should you double-team Shaquille ONeal? (How much? Reduce team or his efficiency?)
Are the Sixers better off without Allen Iverson? (Short or long term?)
How important is a bench or big contracts or biggest contract or a superstar? (To winning a championship?)
Cast things in terms of concepts
What statistics reflect winning?
Gather data
Seasonal and boxscore data readily available
Make estimates
Track own data
Do analyses
Set up equalities, inequalities
Set up time frame
Report in concrete terms
How to convince a non-math person?
Room for soft things, not measured
6. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 6 Example 1: Checking Data Data from Dougstats.com
These are the kind of tasks Id ask for someone to do at an entry levelThese are the kind of tasks Id ask for someone to do at an entry level
7. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 7 Example 1: Checking Data Minutes Team = Minutes Opponents
1442 ? 1444
Sum of Individuals = Team?
Minutes: 116+
+ 121 = 1142
Sum of Games Started/5 = Games?
(6+6+6+6+6)/5 = 6
Minutes/5/Games = 48 if no overtime?
1442/30 = 48.066667 ? 48
Points = 2*FGM + FG3M + FTM
Team FGA FGM >= Team OREB + Opp DREB
8. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 8 Example 2: Basic Analysis Continuing with data from Dougstats.com
Why did Chicago lose to Miami?
Bulls couldnt handle Shaq
Tyson Chandlers injury
Big picture to little picture
9. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 9 Example 2: Basic Analysis Offense or defense?
Possessions = FGA OR + 0.4*FTA + TOV
Average estimates to get 570.3
Rating: Pts/Poss*100
Offense: 590/570.3*100 = 103.5
Defense: 608/570.3*100 = 106.6
Playoff Avg: 107.4
10. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 10 Example 2: Basic Analysis Four Factor Analysis
eFG%: (FGM + 0.5 * FG3M)/FGA
O: 0.497
D: 0.514
Avg: 0.498
TOV%: TOV/Poss
O: 0.161
D: 0.167
Avg: 0.146
11. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 11 Example 2: Basic Analysis Four Factor Analysis (cont.)
OR%: OR/(OR + OppDR)
O: 0.216
D: 0.268
Avg: 0.260
FTratio: FTM/FGA
O: 0.295
D: 0.261
Avg: 0.275
12. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 12 Example 2: Basic Analysis Breaking down eFG%
Was it Shaq?
What was wrong with the Bulls?
The biggest focus of coaching analysis
The biggest focus of coaching analysis
13. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 13 Example 2: Basic Analysis Was it Shaq? Was it Shaq in the post?
In transition?
One specific game?Was it Shaq in the post?
In transition?
One specific game?
14. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 14 Example 2: Basic Analysis What was wrong with the Bulls?
15. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 15 Example 3: Estimation of Rebounds College data for Dwyane Wade (basketball-reference.com)
How many offensive and defensive rebounds?
16. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 16 Example 3: Rebound Estimation Basic:
Offensive rebounds are typically about 30% of total
Oreb = 0.30*420 = 126
Dreb = 420 126 = 294
17. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 17 Example 3: Rebound Estimation More detailed:
From Chicago example, we see breakdown by position:
Use PG info:
Oreb = 0.05*420 = 21
Dreb = 420-21 = 399
18. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 18 Example 3: Rebound Estimation More information:
In 2003, in 28 games, Wade had 52 offensive rebounds and 176 total rebounds
Set OREB = x
x/209 = 52/176 => x = 61.75 ~ 62
Dreb = 209 x
Percentage = 61.75/209 = 29.5%
Assume that percentage
OREB in 2002 = 0.295*211 = 62
DREB in 2002 = 211-62 = 149
19. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 19 Example 4: Opponent Rebound Estimation Available information from ESPN.com:
In 31 games, Arizona 2002 had 334 offensive rebounds, 711 defensive rebounds (1045 total), and went 868-1878 from the field
In 26 games, Arizona 2002 opponents had 898 total rebounds and went 764-1723 from the field
What is their opponents offensive rebounding percentage?
20. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 20 Example 4: Opponent Rebound Estimation Scale and assume 30%?
Scale up: TREB/31 = 898/26
TREB = 1071, OREB = 321, DREB = 750
But
Team FGA FGM >= Team OREB + Opp DREB
Arizona: 1878-868 >= 334 + 750?
1010 < 1084
Opp: (1723-764)*31/26 >= 321 + 711?
1143 >=1032
21. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 21 Example 4: Opponent Rebound Estimation Assume same proportion of Total Rebounds to Missed Shots for Arizona and opponents
(AZ OR + Opp DR)/(AZ FGA AZ FGM) = (Opp OR + AZ DR)/(Opp FGA Opp FGM)
Opp DR + Opp OR = 1071
2 equations and 2 unknowns
Opp OR = 412, Opp DR = 658
OR are 38% of total
(next year, actual was 35%)
22. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 22 Example 5: Unit Conversion Lots of units in basketball:
Per Game
Per 48 minutes
Per 40 minutes
Per Minute
Per Team Possession
Per Individual Possession
23. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 23 Example 6: Percentage of Shots Assisted Data from NBA.com or Dougstats.com
Ray Allen 640-1494 FG, 289 AST, 3069 Minutes
Seattle team 2882-6495 FG, 1483 AST, 19755 Minutes
Multiple factors affect %asstd
Minutes played
Assists by teammates
FGM by teammates
24. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 24 Example 6: Percentage of Shots Assisted One (bad) estimate:
Asstd FG= (Assists by teammates)/(Minutes by teammates)*(Minutes by Player)
=(TmAST AST)/(TmMin Min)*Min
=(1483-289)/(19755-3069)*3069
=220
Doesnt consider FGM by player
25. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 25 Example 6: Percentage of Shots Assisted Better estimate:
%Asstd: Assists by teammates/FGM by teammates
Assists by teammates = (TmAst/TmMin*5*Min Ast)
FGM by teammates = (TmFGM/TmMin*5*Min FGM)
Considers all info, at least indirectly
26. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 26 Example 6: Percentage of Shots Assisted Better estimate:
Sum of chances of each player assisting others
=0.472 (Actual 47%)
See Basketball on Paper, Appendix 1
27. BASKETBALL ON PAPER Dean Oliver
deano@rawbw.com 27 Finally
Repeated experiments!
Use the structure of Basketball on Paper
Are players similar?
Play games
Chart games for data
Other suggestions?