## How to read Win Charts

Below I have some FAQs designed to make the NBA Win Charts I post easy to understand.

### Q: What are “Win Charts”?

A Win Chart is my attempt to explain a team’s wins and losses to date by assigning responsibility for them to the participating players on that team based on each of the player’s minutes played and his marginal efficient production of the basketball statistics that correlate with wins. I’ve found them to be pretty reliable, but that doesn’t mean they’re absolutely bulletproof. I wouldn’t make that claim. The Win Charts are just meant to be an addition to the on-going conversation about who is valuable and who is not in the sport of basketball.

### Q: What is Marginal Win Score?

Marginal Win Score is just an expression of each player’s statistical production per minute compared to the statistical production of the opponents who have played the same position at the same time. The measurement weights each of the statistics according to how its production correlates with winning basketball games (for instance, the number of points a player scores has no meaning in terms of his wins produced unless you also consider the number of possessions he used to score those points). For a much deeper background and explanation of MWS48, I have written a separate page.

### Q: What are “Win__Loss Credits”?

Win__Loss credits are simply the number of team wins and losses I credit each player with producing based on his Marginal Win Score per 48 minutes and the number of minutes he has played.

Here’s how it works. First, I begin with the premise that every player is responsible for 1/5th of a game outcome (a win or a loss) for every 48 minutes he plays, which means each player is responsible for a full game outcome for every 240 minutes he plays.

Basketball games generally last 48 minutes. Each basketball team has five and only five players actively participating at any given moment during each of those 48 minutes. The outcome can only be based upon each active player’s comparative performance. Therefore every 48 minutes a player must be held accountable for 1/5th of an entire game’s outcome.

With that premise as my starting point, I calculate the number of wins the player can be credited with producing (using his MWS48, his minutes played, and then entering the two into the shorthand win production formula created by Professor David Berri). After I get the player’s win total, I get his loss total by dividing his minutes played by 240 and subtracting that result from his win total.

### Q: What is “Win Contribution Index”?

Win Contribution Index is just a “value measurement”. It the product of a player’s Marginal Win Score per 48 multiplied by the percentage of the team’s total playing minutes that he used. Example: If LeBron James played 10% of the Cavaliers total minutes for whatever stretch of time I was examining, and his MWS was +6.50 over that stretch, then his Win Contribution Index number would be +0.650… a very, very good WCI.

What purpose does WCI serve? It allows me to compare any player’s value with any other player’s value over any given period of time… one game, ten games, a season, whatever.

Why not just use win credits for that? Because if you just use win credits you run into two problems.

The first is weighing his win production against his minutes. That’s often hard to determine without some kind of level playing field. WCI gives me that level playing field.

The second reason is over short periods of time, like one single game for instance, “win credits” devolve into confusing and somewhat meaningless integers. Win Contribution Index does not have that problem.

### Q: What is “Player Win Average”?

Player Win Average is a “level of play” measurement. Basically it is the percentage of wins a player is generating for every 240 minutes he is on the floor. Don’t confuse it with a similar statistic used on 82games.com, though. On 82games, their “winning percentage” basically is the score of each game the player appears in while the player was on the floor. (So under 82games system if Charlie Bell is in for 5 minutes and the Bucks score 5 points during those minutes while the Bulls score only 4, Charlie Bell is credited with a “win” for that game).

January 3, 2010 at 2:57 am |

[...] I do, I always calculate every players “Win Contribution Index”. (Please refer to the “Win Charts” page for [...]

January 13, 2010 at 4:17 am |

[...] Analyzing the slow start of the Detroit Pistons By tywill33 Before the All-Star break I’d like to calculate the Marginal Win Score and the consequent wins and losses produced by each player on every NBA team. When I am finished with every team I will produce a page that will provide access to continuously updated NBA Win Charts. [...]

January 13, 2010 at 8:11 am |

With that premise as my starting point, I calculate the number of wins the player can be credited with producing (using his MWS48, his minutes played, and then entering the two into the shorthand win production formula created by Professor David Berri). After I get the player’s win total, I get his loss total by dividing his minutes played by 240 and subtracting that result from his win total.In the past, I thought I understood this, but reading back over it, I’m confused … could you provide an example of one player to show how it works in practice?

March 7, 2010 at 6:30 pm |

[...] you click here, you can see a Win Chart (click here for a primer on how to read the Win Chart) I did for every one of the leading contenders for NBA MVP, with the [...]

May 29, 2010 at 9:56 pm |

[...] This is by far the earliest I have completed “wins produced” calculations for the entire NBA. I haven’t transcribed all of my results onto digital charts yet, but that shouldn’t take more than a few days and I will have all of the data posted, along with my “MWS48″ All-NBA team, which will feature a couple of surprises. For now I want to do one of my favorite features on this blog, “The NBA’s 20 Most Harmful Players” for the season according to each player’s Win Contribution Index. [...]

June 5, 2010 at 11:21 pm |

[...] two month project is over. I have produced, before the end of the postseason, NBA Team Win Charts attributing each team’s wins and losses recorded during the 2009-10 season to the individual [...]

June 7, 2010 at 9:20 am |

[...] a statistic I call “Win Contribution“, which is based upon a player’s Marginal Win Score, I am charting the impact made on [...]

June 11, 2010 at 7:45 am |

[...] big was the Big Baby in Game 4? By tywill33 I usually do “Win Contribution” calculations following an NBA Finals game. But I dropped the ball on Game 3 and it looks [...]

November 15, 2010 at 11:06 pm |

[...] compares the win contributions being made this season by the 20 players who posted the highest win contributions last season. Remember win contribution is a numerical expression of the impact a player is having [...]

November 16, 2010 at 4:17 pm |

[...] Below is the Los Angeles Lakers win chart through and up to tonight’s contest against the Milwaukee Bucks (here’s what the numbers mean). [...]

November 24, 2010 at 11:49 pm |

[...] be measured on both ends of the court, and its counterpart “total value” index I call Win Contribution, I have ranked the most valuable players in the NBA thus far in terms of each player’s [...]