APBRmetrics
Encyclopedia
APBRmetrics is a term sometimes used to refer to the analysis of basketball
through objective evidence, especially basketball statistics
. APBRmetrics is a cousin to the study of baseball statistics
, known as Sabermetrics
, and similarly takes its name from the acronym APBR, which stands for the Association for Professional Basketball Research.
A key tenet for many modern basketball analysts is that basketball is best evaluated at the level of possessions. During a single game, both teams have approximately the same number of possessions, because they alternate possession. (A team can have slightly more if it begins and ends a quarter or half with possession.) However, over the course of the season, teams play at very different paces, which can dramatically color their points scored and points allowed per game. Therefore, these analysts favor use of points scored per 100 possessions (Offensive Rating) and points allowed per 100 possessions (Defensive Rating). A second core tenet is that per-minute statistics are more useful for evaluating players than per-game statistics. From John Hollinger
's Pro Basketball Forecast:
A more complete explanation of possession-based analysis is available in "A Starting Point for Analyzing Basketball Statistics" in the Journal of Quantitative Analysis in Sports.
Coach Frank McGuire
, modern APBRmetrics came into existence when Bill James
gained popularity for his Baseball Abstracts and basketball enthusiasts borrowed some of the ideas and the overall philosophy of the importance of statistical analysis for finetuning achievement. Early APBRmetricians focused on "linear weights" statistics, which assign a value to each key statistic and add and subtract to find a player's total efficiency, usually on a per-minute basis and various brands of this were created and often became the basis for books. Among these people were Dave Heeren, Bob Bellotti, and Martin Manley.
Beginning in the 1990s, Dean Oliver popularized the use of possession statistics. Oliver and John Hollinger
are credited with moving this use of basketball statistics into the view of more basketball fans through their websites in the late 1990s. Oliver published his book Basketball On Paper in 2003, while Hollinger began writing the Pro Basketball Forecast series in 2002.
Several dozen other serious basketball fans/analysts also make regular and helpful contributions to fine-tuning the methods and their usage and advancing new approaches to research questions through the active APBRmetrics forum.
In the wake of the best-selling book Moneyball, which glamorized Sabermetrics, APBRmetric approaches began to receive some attention from the media and NBA teams.{see list of media articles near bottom of this page http://www.sonicscentral.com/statsite.html} The goal was to find a more objective method of analyzing player performance and to find the most productive mix of players within the salary cap or budget.
In 2004, Oliver was hired as a full-time consultant by the Seattle SuperSonics
, making him the first APBRmetrician to be employed by an NBA team full-time.
The Houston Rockets took the movement one step further in April 2006 by hiring Daryl Morey
as their assistant general manager and announcing that he would replace Carroll Dawson as general manager after the 2006-07 season. Morey, previously Senior Vice President of Operations and Information for the Boston Celtics, had provided statistical analysis for the Celtics front office and wrote about advanced statistics for the Celtics Web site but had no traditional basketball experience as a player, coach or scout.
The Web site 82games.com, which debuted in 2003, brought the analysis of plus-minus ratings—how well a team fares with a certain player or lineup on the floor as opposed to on the bench—and counterpart production into the mainstream for basketball (it was a common measurement in ice hockey
). There is also more detail on shooting effectiveness by location on the court and time on clock. These statistics allow APBRmetricians to measure contributions not accounted for by traditional statistics, particularly at the defensive end of the court, an area underdeveloped in the first wave of new stats including PER and the initial player points allowed defensive rating (which was not based on play by play tracking of one on one defense because it was not yet available and also gave heavy weight to points allowed by the rest of the team as well as the player himself. Some now prefer the counterpart and team measures of defense at 82games which are based on written play by play records but aren't perfect either.)
During the 2006 NBA Playoffs, Synergy Sports Technology provided a free trial of a site that combined video of every NBA game with statistical breakdowns of player tendencies similar to those long in use amongst NBA teams—going left vs right, being the ball handler on the pick and roll, etc. This combination of video and statistics is currently being used by a number of NBA teams. Public access has been discontinued indefinitely.
Dr. Ben Alamar is an Assistant Professor of Management at Menlo College
and the founding editor of the Journal of Quantitative Analysis in Sports. He is currently a consultant for the Oklahoma City Thunder
.
Roland Beech is the proprietor of 82games.com and has contributed his analysis to ESPN.com
and SI.com. He is a consultant for the Dallas Mavericks
.
Bob Bellotti was one of the first APBRmetricians, having invented "Points Created," a player rating system that attempted to boil all of a player's contributions into one number (similar to Bill James
' Runs created
). Bellotti wrote several books in the late 1980s and early 1990s, and contributed to the NBA's official encyclopedia, Total Basketball.
David Berri
is a professor of economics
at Southern Utah University
who teamed with peers Martin Schmidt and Stacey Brook to write The Wages of Wins. Published in 2006, the book brought the work of sports economists to a wider group of readers and focused largely on the NBA.
John Ezekowitz writes for the Harvard Sports Analysis Collective, and his research has been cited by ESPN The Magazine
, Sports Illustrated
, and the Wall Street Journal
. He is currently a consultant for the Phoenix Suns
as a statistician.
John Hollinger
authored four books in the Pro Basketball Forecast/Prospectus series and is a regular columnist for ESPN Insider. Hollinger's work is read by many mainstream fans who are not familiar with APBRmetrics in general, making him instrumental in introducing the system to regular NBA fans. Hollinger posts on twoplustwo forums under the handle "JumanjiBoard".
Justin Kubatko developed and administers Basketball-Reference.com, a site that provides much relied upon and easy access to regular and many of the advanced basketball statistics, much of the data not available anywhere else on the net for before the most recent seasons. He also adapted Bill James
' Win Shares
to basketball to estimate player contribution to a team's wins, based on individual offensive performance and team defense while the player is on the court. ESPN.com
has called the site "[T]he world's best hoops history site."
Dr. Dean Oliver is a former player and assistant coach at Cal Tech and a scout, who has consulted with the Seattle Supersonics and also served in the front office of the Denver Nuggets
. He currently works for ESPN. His old website, Journal of Basketball Studies, and subsequent 2003 book, Basketball on Paper, brought him recognition as a principal leader in the field. His research dealt with the importance of pace and possessions, how teamwork affects individual statistics, defensive statistics, and the importance of a player's ability to create their own shot. His efforts to bring focus on the Four Factors of Basketball Success (field-goal shooting, offensive rebounds, turnovers and getting to the free-throw line) also help provide a simple framework for evaluation of players and teams.
Kevin "Al" Pelton is a sportswriter who writes for BasketballProspectus.com and has written for 82games.com, Hoopsworld.com and SI.com. Pelton also covers the Seattle Storm
for the team's Web site, stormbasketball.com, and formerly covered the Seattle SuperSonics
. However, after the SuperSonics' departure from Seattle, he has "adopted" the Portland Trail Blazers
in his coverage. He has worked to acquaint mainstream basketball fans with statistical analysis, and he moderates the APBRmetrics forum. He is also a consultant for the Indiana Pacers
.
Dan Rosenbaum is a consultant for the Cleveland Cavaliers
. Rosenbaum's work has focused on adjusted plus-minus ratings, which takes into account the quality of the players playing with and against a player and adjusts his plus-minus accordingly.
Jeff Sagarin
and Wayne Winston pioneered adjusted plus-minus statistics with their WINVAL system, which has been used extensively by the Dallas Mavericks
.
Offensive Rating/Offensive Efficiency and Defensive Rating/Defensive Efficiency, on a team level, are calculated as points scored and points allowed per 100 possessions. Possessions are usually estimated by the following formula:
The .44 accounts for the fact that when a player scores a basket and is fouled, they shoot a free throw, which is not a possession. This is also true of flagrant fouls and technical fouls, while three free throws make up one possession when a player is fouled shooting a 3-pointer. It should also be noted that when analyzing College Basketball
, APBRmetricians have used .475 as the free-throw multiplier, since the NCAA's rules about the team foul limit differ from those in the NBA.
Offensive rebounds are subtracted because grabbing an offensive rebound simply extends the original possession, rather than creating a new possession. If offensive rebounds were not subtracted in this manner, opposing teams would not necessarily have the same number of possessions in a game.
The .96 multiplier adjusts for team rebounds. Because these are not considered offensive rebounds, the formula slightly overestimates the number of possessions per team without the multiplier.
Therefore, team ratings are simply calculated as:
and
In addition to pioneering team offensive and defensive ratings, Dean Oliver adapted them to players in his book Basketball on Paper.
Effective Field-Goal Percentage (eFG%) accounts for the fact that 3-pointers are worth an extra point, something ignored by traditional field-goal percentage. Why is this important? Imagine a situation where one player shoots 6 layups, and makes 3 of them, while another player shoots 6 three point shots and makes 2 of them. Both players have scored 6 points on 6 shots, yet the first player's FG% is 50 percent, and the second player's FG% is only 33 percent. The second player looks like a terrible shooter even though he has scored just as many points on just as many shots. Effective field-goal percentage corrects for this by accounting for the extra point that 3-pointers are worth.
The formula is:
True Shooting Percentage takes this a step further by factoring in free throws. It is essentially points scored per shooting possession, but divided by two to look like field-goal percentage—PTS/(2*(FGA + (.44*FTA)))
Rebound Rate is the estimated percentage of available rebounds a player or team grabs.
Player Efficiency Rating
is John Hollinger
's linear-weights rating for a player's per-minute performance which reduces a player's total performance into a single number.
Pythagorean Record
is what a team's expected record is based on points scored or allowed. This can be found by PF^14/(PF^14 + PA^14)
There are also several versions of passing ratings, a usage rating that measures how well a player does with the possession he uses, other general and skill specific defensive ratings and many other statistics and analytic ratios to aid understanding of player and team performance.
Basketball
Basketball is a team sport in which two teams of five players try to score points by throwing or "shooting" a ball through the top of a basketball hoop while following a set of rules...
through objective evidence, especially basketball statistics
Basketball statistics
Statistics in basketball are kept to evaluate a player or a team's performance.Some statistics are* GP, GS: games played, games started* PTS: points* FGM, FGA, FG%: field goals made, attempted and percentage...
. APBRmetrics is a cousin to the study of baseball statistics
Baseball statistics
Statistics play an important role in summarizing baseball performance and evaluating players in the sport.Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itself to easy record-keeping and statistics...
, known as Sabermetrics
Sabermetrics
Sabermetrics is the specialized analysis of baseball through objective, empirical evidence, specifically baseball statistics that measure in-game activity. The term is derived from the acronym SABR, which stands for the Society for American Baseball Research...
, and similarly takes its name from the acronym APBR, which stands for the Association for Professional Basketball Research.
A key tenet for many modern basketball analysts is that basketball is best evaluated at the level of possessions. During a single game, both teams have approximately the same number of possessions, because they alternate possession. (A team can have slightly more if it begins and ends a quarter or half with possession.) However, over the course of the season, teams play at very different paces, which can dramatically color their points scored and points allowed per game. Therefore, these analysts favor use of points scored per 100 possessions (Offensive Rating) and points allowed per 100 possessions (Defensive Rating). A second core tenet is that per-minute statistics are more useful for evaluating players than per-game statistics. From John Hollinger
John Hollinger
John Hollinger is an analyst and writer for ESPN. He primarily covers the NBA. Hollinger grew up in Mahwah, New Jersey and is a 1993 graduate of the University of Virginia....
's Pro Basketball Forecast:
- "It's a pretty simple concept, but one that has largely escaped most NBA front offices: The idea that what a player does on a per-minute basis is far more important than his per-game stats. The latter tend to be influenced more by playing time than by quality of play, yet remain the most common metric of player performance."
A more complete explanation of possession-based analysis is available in "A Starting Point for Analyzing Basketball Statistics" in the Journal of Quantitative Analysis in Sports.
History
While the use of possession stats dates back at least as far as former North CarolinaUniversity of North Carolina at Chapel Hill
The University of North Carolina at Chapel Hill is a public research university located in Chapel Hill, North Carolina, United States...
Coach Frank McGuire
Frank McGuire
Frank Joseph McGuire was an American athletic coach who gained his greatest renown in collegiate basketball....
, modern APBRmetrics came into existence when Bill James
Bill James
George William “Bill” James is a baseball writer, historian, and statistician whose work has been widely influential. Since 1977, James has written more than two dozen books devoted to baseball history and statistics...
gained popularity for his Baseball Abstracts and basketball enthusiasts borrowed some of the ideas and the overall philosophy of the importance of statistical analysis for finetuning achievement. Early APBRmetricians focused on "linear weights" statistics, which assign a value to each key statistic and add and subtract to find a player's total efficiency, usually on a per-minute basis and various brands of this were created and often became the basis for books. Among these people were Dave Heeren, Bob Bellotti, and Martin Manley.
Beginning in the 1990s, Dean Oliver popularized the use of possession statistics. Oliver and John Hollinger
John Hollinger
John Hollinger is an analyst and writer for ESPN. He primarily covers the NBA. Hollinger grew up in Mahwah, New Jersey and is a 1993 graduate of the University of Virginia....
are credited with moving this use of basketball statistics into the view of more basketball fans through their websites in the late 1990s. Oliver published his book Basketball On Paper in 2003, while Hollinger began writing the Pro Basketball Forecast series in 2002.
Several dozen other serious basketball fans/analysts also make regular and helpful contributions to fine-tuning the methods and their usage and advancing new approaches to research questions through the active APBRmetrics forum.
In the wake of the best-selling book Moneyball, which glamorized Sabermetrics, APBRmetric approaches began to receive some attention from the media and NBA teams.{see list of media articles near bottom of this page http://www.sonicscentral.com/statsite.html} The goal was to find a more objective method of analyzing player performance and to find the most productive mix of players within the salary cap or budget.
In 2004, Oliver was hired as a full-time consultant by the Seattle SuperSonics
Seattle SuperSonics
The Seattle SuperSonics were an American professional basketball team based in Seattle, Washington that played in the Pacific and Northwest Divisions of the National Basketball Association from 1967 until 2008. Following the 2007–08 season, the team relocated to Oklahoma City, and now plays as...
, making him the first APBRmetrician to be employed by an NBA team full-time.
The Houston Rockets took the movement one step further in April 2006 by hiring Daryl Morey
Daryl Morey
Daryl Morey is an American sports executive. He is the current general manager of the Houston Rockets of the National Basketball Association. He was named Assistant General Manager on April 3, 2006 and succeeded Carroll Dawson as General Manager on May 10, 2007...
as their assistant general manager and announcing that he would replace Carroll Dawson as general manager after the 2006-07 season. Morey, previously Senior Vice President of Operations and Information for the Boston Celtics, had provided statistical analysis for the Celtics front office and wrote about advanced statistics for the Celtics Web site but had no traditional basketball experience as a player, coach or scout.
The Web site 82games.com, which debuted in 2003, brought the analysis of plus-minus ratings—how well a team fares with a certain player or lineup on the floor as opposed to on the bench—and counterpart production into the mainstream for basketball (it was a common measurement in ice hockey
Ice hockey
Ice hockey, often referred to as hockey, is a team sport played on ice, in which skaters use wooden or composite sticks to shoot a hard rubber puck into their opponent's net. The game is played between two teams of six players each. Five members of each team skate up and down the ice trying to take...
). There is also more detail on shooting effectiveness by location on the court and time on clock. These statistics allow APBRmetricians to measure contributions not accounted for by traditional statistics, particularly at the defensive end of the court, an area underdeveloped in the first wave of new stats including PER and the initial player points allowed defensive rating (which was not based on play by play tracking of one on one defense because it was not yet available and also gave heavy weight to points allowed by the rest of the team as well as the player himself. Some now prefer the counterpart and team measures of defense at 82games which are based on written play by play records but aren't perfect either.)
During the 2006 NBA Playoffs, Synergy Sports Technology provided a free trial of a site that combined video of every NBA game with statistical breakdowns of player tendencies similar to those long in use amongst NBA teams—going left vs right, being the ball handler on the pick and roll, etc. This combination of video and statistics is currently being used by a number of NBA teams. Public access has been discontinued indefinitely.
Prominent APBRmetricians
The growing field of quantitative analysts includes the following:Dr. Ben Alamar is an Assistant Professor of Management at Menlo College
Menlo College
Menlo College, often referred to as Menlo, is a private, four-year baccalaureate college specializing in business located in the Silicon Valley town of Atherton, California.-Campus:...
and the founding editor of the Journal of Quantitative Analysis in Sports. He is currently a consultant for the Oklahoma City Thunder
Oklahoma City Thunder
The Oklahoma City Thunder are a professional basketball franchise based in Oklahoma City, Oklahoma. They play in the Northwest Division of the Western Conference in the National Basketball Association ; their home court is at Chesapeake Energy Arena....
.
Roland Beech is the proprietor of 82games.com and has contributed his analysis to ESPN.com
ESPN.com
ESPN.com is the official website of ESPN and a division of ESPN Inc. Since launching in 1995 as ESPNet.SportsZone.com, the website has developed numerous sections including: Page 2, SportsNation, ESPN 3.com, ESPN Motion, My ESPN, ESPN Sports Travel, ESPN Video Games, ESPN Insider, ESPN.com's...
and SI.com. He is a consultant for the Dallas Mavericks
Dallas Mavericks
The Dallas Mavericks are a professional basketball team based in Dallas, Texas. They are members of the Southwest Division of the Western Conference of the National Basketball Association , and the reigning NBA champions, having defeated the Miami Heat in the 2011 NBA Finals.According to a 2011...
.
Bob Bellotti was one of the first APBRmetricians, having invented "Points Created," a player rating system that attempted to boil all of a player's contributions into one number (similar to Bill James
Bill James
George William “Bill” James is a baseball writer, historian, and statistician whose work has been widely influential. Since 1977, James has written more than two dozen books devoted to baseball history and statistics...
' Runs created
Runs created
Runs created is a baseball statistic invented by Bill James to estimate the number of runs a hitter contributes to his team.-Purpose:James explains in his book, The Bill James Historical Baseball Abstract, why he believes runs created is an essential thing to measure:With regard to an offensive...
). Bellotti wrote several books in the late 1980s and early 1990s, and contributed to the NBA's official encyclopedia, Total Basketball.
David Berri
David Berri
David J. Berri is a sports economist and an professor of economics at Southern Utah University, known for his sometimes-controversial analysis of NBA basketball...
is a professor of economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...
at Southern Utah University
Southern Utah University
Southern Utah University, or SUU, is located in Cedar City, Utah. It was founded in 1897 as an extension of the Agricultural College of Utah, by the citizens of Cedar City.During its history, the school has been known as:...
who teamed with peers Martin Schmidt and Stacey Brook to write The Wages of Wins. Published in 2006, the book brought the work of sports economists to a wider group of readers and focused largely on the NBA.
John Ezekowitz writes for the Harvard Sports Analysis Collective, and his research has been cited by ESPN The Magazine
ESPN The Magazine
ESPN The Magazine is a bi-weekly sports magazine published by the ESPN sports network in Bristol, Connecticut in the United States. The first issue was published on March 11, 1998....
, Sports Illustrated
Sports Illustrated
Sports Illustrated is an American sports media company owned by media conglomerate Time Warner. Its self titled magazine has over 3.5 million subscribers and is read by 23 million adults each week, including over 18 million men. It was the first magazine with circulation over one million to win the...
, and the Wall Street Journal
The Wall Street Journal
The Wall Street Journal is an American English-language international daily newspaper. It is published in New York City by Dow Jones & Company, a division of News Corporation, along with the Asian and European editions of the Journal....
. He is currently a consultant for the Phoenix Suns
Phoenix Suns
The Phoenix Suns are a professional basketball team based in Phoenix, Arizona. They are members of the Pacific Division of the Western Conference in the National Basketball Association and the only team in their division not to be based in California. Their home arena since 1992 has been the US...
as a statistician.
John Hollinger
John Hollinger
John Hollinger is an analyst and writer for ESPN. He primarily covers the NBA. Hollinger grew up in Mahwah, New Jersey and is a 1993 graduate of the University of Virginia....
authored four books in the Pro Basketball Forecast/Prospectus series and is a regular columnist for ESPN Insider. Hollinger's work is read by many mainstream fans who are not familiar with APBRmetrics in general, making him instrumental in introducing the system to regular NBA fans. Hollinger posts on twoplustwo forums under the handle "JumanjiBoard".
Justin Kubatko developed and administers Basketball-Reference.com, a site that provides much relied upon and easy access to regular and many of the advanced basketball statistics, much of the data not available anywhere else on the net for before the most recent seasons. He also adapted Bill James
Bill James
George William “Bill” James is a baseball writer, historian, and statistician whose work has been widely influential. Since 1977, James has written more than two dozen books devoted to baseball history and statistics...
' Win Shares
Win Shares
Win shares is the name of the metric Bill James describes in his 2002 book Win Shares.It considers statistics for baseball and basketball players, in the context of their team and in a sabermetric way, and assigns a single number to each player for his contributions for the year. A win share...
to basketball to estimate player contribution to a team's wins, based on individual offensive performance and team defense while the player is on the court. ESPN.com
ESPN.com
ESPN.com is the official website of ESPN and a division of ESPN Inc. Since launching in 1995 as ESPNet.SportsZone.com, the website has developed numerous sections including: Page 2, SportsNation, ESPN 3.com, ESPN Motion, My ESPN, ESPN Sports Travel, ESPN Video Games, ESPN Insider, ESPN.com's...
has called the site "[T]he world's best hoops history site."
Dr. Dean Oliver is a former player and assistant coach at Cal Tech and a scout, who has consulted with the Seattle Supersonics and also served in the front office of the Denver Nuggets
Denver Nuggets
The Denver Nuggets are a professional basketball team based in Denver, Colorado. They play in the National Basketball Association . They were founded as the Denver Rockets in 1967 as a charter franchise of the American Basketball Association, and became one of that league's more successful teams...
. He currently works for ESPN. His old website, Journal of Basketball Studies, and subsequent 2003 book, Basketball on Paper, brought him recognition as a principal leader in the field. His research dealt with the importance of pace and possessions, how teamwork affects individual statistics, defensive statistics, and the importance of a player's ability to create their own shot. His efforts to bring focus on the Four Factors of Basketball Success (field-goal shooting, offensive rebounds, turnovers and getting to the free-throw line) also help provide a simple framework for evaluation of players and teams.
Kevin "Al" Pelton is a sportswriter who writes for BasketballProspectus.com and has written for 82games.com, Hoopsworld.com and SI.com. Pelton also covers the Seattle Storm
Seattle Storm
The Seattle Storm is a professional basketball team based in Seattle, Washington, playing in the Western Conference in the Women's National Basketball Association . The team was founded before the 2000 season began...
for the team's Web site, stormbasketball.com, and formerly covered the Seattle SuperSonics
Seattle SuperSonics
The Seattle SuperSonics were an American professional basketball team based in Seattle, Washington that played in the Pacific and Northwest Divisions of the National Basketball Association from 1967 until 2008. Following the 2007–08 season, the team relocated to Oklahoma City, and now plays as...
. However, after the SuperSonics' departure from Seattle, he has "adopted" the Portland Trail Blazers
Portland Trail Blazers
The Portland Trail Blazers, commonly known as the Blazers, are an American professional basketball team based in Portland, Oregon. They play in the Northwest Division of the Western Conference in the National Basketball Association . The Trail Blazers originally played their home games in the...
in his coverage. He has worked to acquaint mainstream basketball fans with statistical analysis, and he moderates the APBRmetrics forum. He is also a consultant for the Indiana Pacers
Indiana Pacers
The Indiana Pacers are a professional basketball team based in Indianapolis, Indiana. They are members of the Central Division of the Eastern Conference of the National Basketball Association...
.
Dan Rosenbaum is a consultant for the Cleveland Cavaliers
Cleveland Cavaliers
The Cleveland Cavaliers are a professional basketball team based in Cleveland, Ohio. They began playing in the National Basketball Association in 1970 as an expansion team...
. Rosenbaum's work has focused on adjusted plus-minus ratings, which takes into account the quality of the players playing with and against a player and adjusts his plus-minus accordingly.
Jeff Sagarin
Jeff Sagarin
Jeff Sagarin is an American sports statistician well-known for his development of a methodology for ranking and rating sports teams in a variety of sports...
and Wayne Winston pioneered adjusted plus-minus statistics with their WINVAL system, which has been used extensively by the Dallas Mavericks
Dallas Mavericks
The Dallas Mavericks are a professional basketball team based in Dallas, Texas. They are members of the Southwest Division of the Western Conference of the National Basketball Association , and the reigning NBA champions, having defeated the Miami Heat in the 2011 NBA Finals.According to a 2011...
.
Common statistics
Among the growing list of APBRmetric basketball statistics here are some of the most important ones gaining increased usage:Offensive Rating/Offensive Efficiency and Defensive Rating/Defensive Efficiency, on a team level, are calculated as points scored and points allowed per 100 possessions. Possessions are usually estimated by the following formula:
The .44 accounts for the fact that when a player scores a basket and is fouled, they shoot a free throw, which is not a possession. This is also true of flagrant fouls and technical fouls, while three free throws make up one possession when a player is fouled shooting a 3-pointer. It should also be noted that when analyzing College Basketball
College basketball
College basketball most often refers to the USA basketball competitive governance structure established by the National Collegiate Athletic Association . Basketball in the NCAA is divided into three divisions: Division I, Division II and Division III....
, APBRmetricians have used .475 as the free-throw multiplier, since the NCAA's rules about the team foul limit differ from those in the NBA.
Offensive rebounds are subtracted because grabbing an offensive rebound simply extends the original possession, rather than creating a new possession. If offensive rebounds were not subtracted in this manner, opposing teams would not necessarily have the same number of possessions in a game.
The .96 multiplier adjusts for team rebounds. Because these are not considered offensive rebounds, the formula slightly overestimates the number of possessions per team without the multiplier.
Therefore, team ratings are simply calculated as:
and
In addition to pioneering team offensive and defensive ratings, Dean Oliver adapted them to players in his book Basketball on Paper.
Effective Field-Goal Percentage (eFG%) accounts for the fact that 3-pointers are worth an extra point, something ignored by traditional field-goal percentage. Why is this important? Imagine a situation where one player shoots 6 layups, and makes 3 of them, while another player shoots 6 three point shots and makes 2 of them. Both players have scored 6 points on 6 shots, yet the first player's FG% is 50 percent, and the second player's FG% is only 33 percent. The second player looks like a terrible shooter even though he has scored just as many points on just as many shots. Effective field-goal percentage corrects for this by accounting for the extra point that 3-pointers are worth.
The formula is:
True Shooting Percentage takes this a step further by factoring in free throws. It is essentially points scored per shooting possession, but divided by two to look like field-goal percentage—PTS/(2*(FGA + (.44*FTA)))
Rebound Rate is the estimated percentage of available rebounds a player or team grabs.
Player Efficiency Rating
Player Efficiency Rating
The Player Efficiency Rating is ESPN Insider writer John Hollinger's all-in-one basketball rating, which attempts to boil down all of a player's contributions into one number. Using a detailed formula, Hollinger developed a system that rates every player's statistical performance.-Introduction:PER...
is John Hollinger
John Hollinger
John Hollinger is an analyst and writer for ESPN. He primarily covers the NBA. Hollinger grew up in Mahwah, New Jersey and is a 1993 graduate of the University of Virginia....
's linear-weights rating for a player's per-minute performance which reduces a player's total performance into a single number.
Pythagorean Record
Pythagorean expectation
Pythagorean expectation is a formula invented by Bill James to estimate how many games a baseball team "should" have won based on the number of runs they scored and allowed. Comparing a team's actual and Pythagorean winning percentage can be used to evaluate how lucky that team was...
is what a team's expected record is based on points scored or allowed. This can be found by PF^14/(PF^14 + PA^14)
There are also several versions of passing ratings, a usage rating that measures how well a player does with the possession he uses, other general and skill specific defensive ratings and many other statistics and analytic ratios to aid understanding of player and team performance.
External links
- APBRmetrics Message Board The central discussion source for APBRmetrics
- 82games.com A wealth of player and team data, +/-, counterpart, by position, time on clock. Also conducts in-depth studies of specialized questions often asked before but not rigorously analyzed.
- AlleyOop.com, Hollinger's Web site (mainly good for links to articles, book buying and archives)
- apbr.org Home of the Association for Professional Basketball Research.
- APBRmetrics Central Another list of resources
- BasketballProspectus.com A new online basketball analysis site from the publishers of the Baseball Prospectus.
- Basketball-Reference.com, historical stats with an APBRmetrics influence
- BasketballValue.com, raw plus-minus and lineup data
- BellottiBasketball.com, statistical consulting service for professional basketball teams
- BBALLsports.com, Bob Chaikin's site for computer basketball simulation and historical sports statistics database
- BasketballResearch.info, Professional Basketball Research
- CountTheBasket.com the most comprehensive index of available stats by type and date on various sites around the web.
- DougStats.com, raw statistical data that can be copied into Excel for manipulation.
- Hollinger's ESPN Insider Archive
- HoopsAnalyst.com, research columns and a strong set of information regarding trades
- Hoopsstats .com A wide range of player and team statistics and many often unique splits.
- Hoopdata.com, daily advanced box scores, advanced statistics, analysis and shot locations.
- Journal of Basketball Statistics, Oliver's Web site (primarily useful to understand definitions if you do not have his newer book and to archive his early work)
- Ken Pomeroy's site, which tracks stats for College BasketballCollege basketballCollege basketball most often refers to the USA basketball competitive governance structure established by the National Collegiate Athletic Association . Basketball in the NCAA is divided into three divisions: Division I, Division II and Division III....
including advanced NCAA stats - KnickerBlogger.Net Stats Page Another important hub for advanced statistical data, it lists current player PER ratings, allows viewing of league leaders by specific advanced stats not always found at mainstream sport sites, team offense and defensive efficiency ratings and the Four Factor ratings
- PopcornMachine.net, game flows (charts player movement in and out of the game aiding but not totally settling the question of who guarded whom).
- "Rocket Science", Houston Press article on Daryl Morey using statistical analysis to manage the Houston Rockets.
- http://www.bepress.com/jqas/vol3/iss4/1/, "Using Box Scores to Analyze a Position's Value to WInning Games." A recent academic research paper looking at impact of player contributions by position and by statistical category.
- puresabermetrics.com, Sports picks based on APBRmetrics
- apbrmetrics.com, APBRmetric website with projections, links, articles