DenButsu

09-04-2010, 02:30 AM

The idea for this thread is that it can be a place where people can discuss, explain, ask about and debate the meaning and use of basketball statistics in general, but more specifically advanced stats.

Here are some resources where you can find the stats themselves as well as statistical analysis blogs, primers, essays, and books:

Websites:

Basketball-Reference (http://www.basketball-reference.com/)

82games.com (http://www.82games.com/)

Basketball Value (http://www.basketballvalue.com/index.php)

HoopData (http://hoopdata.com/default.aspx)

Hardwood Paroxysm (http://www.hardwoodparoxysm.com/)

Basketball Prospectus (http://www.basketballprospectus.com/)

APBRmetrics (http://sonicscentral.com/apbrmetrics/index.php)

NBAstuffer.com (http://www.nbastuffer.com/)

PopcornMachine.net (http://popcornmachine.net/)

Basketball Geek (http://www.basketballgeek.com/data/)

Stats by Numbers (http://statsbynumbers.com/about/)

Team Rankings (http://www.teamrankings.com/nba/stats/)

twitter:

http://twitter.com/tomhaberstroh (http://twitter.com/tomhaberstroh)

http://twitter.com/Hoopdata (http://twitter.com/Hoopdata)

http://twitter.com/bball_ref (http://twitter.com/bball_ref)

http://twitter.com/HPbasketball (http://twitter.com/HPbasketball)

http://twitter.com/basketballvalue (http://twitter.com/basketballvalue)

http://twitter.com/johnhollinger (http://twitter.com/johnhollinger)

http://twitter.com/dmorey (http://twitter.com/dmorey)

Books:

Basketball On Paper, by Dean Oliver (http://www.basketballonpaper.com/)

Primers, Glossaries, & Some Introductory Advanced Stats:

And here are a few good elementary primers on some of the main advanced metrics.

Click here for The Basketball Notebook Stats Primer (http://basketballnotebook.blogspot.com/2005/12/basketball-notebook-stats-primer.html) for a good overview.

Two great glossary/dictionary type references can be found at the following links:

The BBR Blog-tionary (http://www.basketball-reference.com/blog/?p=1120)

-and-

an Advanced Statistics Glossary (http://sonicscentral.com/apbrmetrics/viewtopic.php?t=2527) at APBRmetrics

Here, from Ben Q Rock at the Orlando Pinstriped Post, are a few more detailed primers which introduce some specific stats and concepts:

Advanced Metrics Handbook, Vol. 1: Effective Field Goal Percentage (http://www.orlandopinstripedpost.com/2010/8/11/1617132/advanced-metrics-handbook-vol-1)

The formula:

(FG + 0.5 * 3P) / FGA

Advanced Metrics Handbook, Vol. 2: True Shooting Percentage (http://www.orlandopinstripedpost.com/2010/8/16/1624997/advanced-metrics-handbook-vol-2)

The formula:

Points / (2 * (FGA + 0.44 * FTA))

Advanced Metrics Handbook, Vol. 3: Pace (http://www.orlandopinstripedpost.com/2010/9/2/1662377/advanced-metrics-handbook-vol-3)

The formula:

0.96 * (FGA + 0.44 * FTA + TO - OReb

From another thread, here Chronz' explanation of why that ".44" number is in the TS% formula:

Let me word it differently, if 44% of each free throw cost a possession then 1 pair of free throws take .88 right. The other 12% come from either AND1's technicals, flagrants, clear-path fouls, or as the third part of a shooting foul from behind the three-point arc.

Mathematically speaking, you start with a FTA = 1/2 a possession or 0.5, then you deduct for those 12% aforementioned sequences, where 0.5 * 0.12 = 0.06 and 0.5 - 0.06 = 0.44

And also from another thread, here's patsSOXknicks' breakdown of the difference between assist % and assist ratio:

Basketball-reference has Ast% vs. what they have on ESPN and Hoopdata with Assist Ratio. These are different statistics and they do have different meanings.

From basketball-reference

AST%

Assist Percentage (available since the 1964-65 season in the NBA); the formula is 100 * AST / (((MP / (Tm MP / 5)) * Tm FG) - FG). Assist percentage is an estimate of the percentage of teammate field goals a player assisted while he was on on the floor.

From ESPN

AST: Assist Ratio - the percentage of a player's possessions that ends in an assist. Assist Ratio = (Assists x 100) divided by [(FGA + (FTA x 0.44) + Assists + Turnovers]

Both of these stats are better then assists per game as that completely ignores pace.

A look at the league leaders:

http://www.basketball-reference.com/leagues/NBA_2010_leaders.html

http://insider.espn.go.com/nba/hollinger/statistics?sort=assistRatio&action=login&appRedirect=http%3a%2f%2finsider.espn.go.com%2fnba %2fhollinger%2fstatistics%3fsort%3dassistRatio

Pretty different. Why? Well upon closer look, the guys with really high Ast% have higher USG% too compared to the guys with just high Assist Ratios. Lebron is not even on the league leaders for Assist Ratio but he's 5th in Ast%- it's because he's 2nd in the NBA in usage rate. So he's going to Ast on a really high percentage of his teams FG because he's used more (and is obviously a good passer too) then say someone like Jason Kidd who doesn't have everything run through him all the time. So for the possessions that Jason Kidd is involved in, a very high % of them end in an assist but the % of the teams FG that he assisted won't be as high since his USG rate isn't as high and because Ast% is based on the minutes you're on the floor, not on the possessions in which you're involved in.

---------------------------------

That should hopefully be enough to get us started. :cool:

Also, as I did with this thread, maybe it would be a good idea for anyone who posts stat-oriented threads in any of the NBA forums to tag them with the "nba stats" tag, so that posters who are interested in this stuff can easily find them across all the forums.

Enjoy! :cheers:

Here are some resources where you can find the stats themselves as well as statistical analysis blogs, primers, essays, and books:

Websites:

Basketball-Reference (http://www.basketball-reference.com/)

82games.com (http://www.82games.com/)

Basketball Value (http://www.basketballvalue.com/index.php)

HoopData (http://hoopdata.com/default.aspx)

Hardwood Paroxysm (http://www.hardwoodparoxysm.com/)

Basketball Prospectus (http://www.basketballprospectus.com/)

APBRmetrics (http://sonicscentral.com/apbrmetrics/index.php)

NBAstuffer.com (http://www.nbastuffer.com/)

PopcornMachine.net (http://popcornmachine.net/)

Basketball Geek (http://www.basketballgeek.com/data/)

Stats by Numbers (http://statsbynumbers.com/about/)

Team Rankings (http://www.teamrankings.com/nba/stats/)

twitter:

http://twitter.com/tomhaberstroh (http://twitter.com/tomhaberstroh)

http://twitter.com/Hoopdata (http://twitter.com/Hoopdata)

http://twitter.com/bball_ref (http://twitter.com/bball_ref)

http://twitter.com/HPbasketball (http://twitter.com/HPbasketball)

http://twitter.com/basketballvalue (http://twitter.com/basketballvalue)

http://twitter.com/johnhollinger (http://twitter.com/johnhollinger)

http://twitter.com/dmorey (http://twitter.com/dmorey)

Books:

Basketball On Paper, by Dean Oliver (http://www.basketballonpaper.com/)

Primers, Glossaries, & Some Introductory Advanced Stats:

And here are a few good elementary primers on some of the main advanced metrics.

Click here for The Basketball Notebook Stats Primer (http://basketballnotebook.blogspot.com/2005/12/basketball-notebook-stats-primer.html) for a good overview.

Two great glossary/dictionary type references can be found at the following links:

The BBR Blog-tionary (http://www.basketball-reference.com/blog/?p=1120)

-and-

an Advanced Statistics Glossary (http://sonicscentral.com/apbrmetrics/viewtopic.php?t=2527) at APBRmetrics

Here, from Ben Q Rock at the Orlando Pinstriped Post, are a few more detailed primers which introduce some specific stats and concepts:

Advanced Metrics Handbook, Vol. 1: Effective Field Goal Percentage (http://www.orlandopinstripedpost.com/2010/8/11/1617132/advanced-metrics-handbook-vol-1)

The formula:

(FG + 0.5 * 3P) / FGA

Advanced Metrics Handbook, Vol. 2: True Shooting Percentage (http://www.orlandopinstripedpost.com/2010/8/16/1624997/advanced-metrics-handbook-vol-2)

The formula:

Points / (2 * (FGA + 0.44 * FTA))

Advanced Metrics Handbook, Vol. 3: Pace (http://www.orlandopinstripedpost.com/2010/9/2/1662377/advanced-metrics-handbook-vol-3)

The formula:

0.96 * (FGA + 0.44 * FTA + TO - OReb

From another thread, here Chronz' explanation of why that ".44" number is in the TS% formula:

Let me word it differently, if 44% of each free throw cost a possession then 1 pair of free throws take .88 right. The other 12% come from either AND1's technicals, flagrants, clear-path fouls, or as the third part of a shooting foul from behind the three-point arc.

Mathematically speaking, you start with a FTA = 1/2 a possession or 0.5, then you deduct for those 12% aforementioned sequences, where 0.5 * 0.12 = 0.06 and 0.5 - 0.06 = 0.44

And also from another thread, here's patsSOXknicks' breakdown of the difference between assist % and assist ratio:

Basketball-reference has Ast% vs. what they have on ESPN and Hoopdata with Assist Ratio. These are different statistics and they do have different meanings.

From basketball-reference

AST%

Assist Percentage (available since the 1964-65 season in the NBA); the formula is 100 * AST / (((MP / (Tm MP / 5)) * Tm FG) - FG). Assist percentage is an estimate of the percentage of teammate field goals a player assisted while he was on on the floor.

From ESPN

AST: Assist Ratio - the percentage of a player's possessions that ends in an assist. Assist Ratio = (Assists x 100) divided by [(FGA + (FTA x 0.44) + Assists + Turnovers]

Both of these stats are better then assists per game as that completely ignores pace.

A look at the league leaders:

http://www.basketball-reference.com/leagues/NBA_2010_leaders.html

http://insider.espn.go.com/nba/hollinger/statistics?sort=assistRatio&action=login&appRedirect=http%3a%2f%2finsider.espn.go.com%2fnba %2fhollinger%2fstatistics%3fsort%3dassistRatio

Pretty different. Why? Well upon closer look, the guys with really high Ast% have higher USG% too compared to the guys with just high Assist Ratios. Lebron is not even on the league leaders for Assist Ratio but he's 5th in Ast%- it's because he's 2nd in the NBA in usage rate. So he's going to Ast on a really high percentage of his teams FG because he's used more (and is obviously a good passer too) then say someone like Jason Kidd who doesn't have everything run through him all the time. So for the possessions that Jason Kidd is involved in, a very high % of them end in an assist but the % of the teams FG that he assisted won't be as high since his USG rate isn't as high and because Ast% is based on the minutes you're on the floor, not on the possessions in which you're involved in.

---------------------------------

That should hopefully be enough to get us started. :cool:

Also, as I did with this thread, maybe it would be a good idea for anyone who posts stat-oriented threads in any of the NBA forums to tag them with the "nba stats" tag, so that posters who are interested in this stuff can easily find them across all the forums.

Enjoy! :cheers: