"Win Contribution" is my own invention, derived from the work done by those who created the "Win Score" metric.
Win Contribution is, in simple terms, a multiplication of each player's "Position Adjusted Win Score" by his percentage of overall playing time.
Here's how it works. If you add up every player's Win Contribution, and plug it into the formula below, you can very accurately calculate the team's expected win total. As a result, each player's "Win Contribution" is a precise numerical expression of the impact that player has had on making his team either a winning or a losing team.
That's because if the sum of every player's Win Contribution adds up to ".000", the expected win total for the team would be dead even, i.e. you would have a .500 team. Thus, any Win Contribution number that is positive indicates the player has contributed to making the team a winning team. And the opposite is true for negative Win Contribution numbers.
Here's a rough guide to how to read the number:
A Win Contribution of "+ .500" means that if you surrounded that player with a roster of average players (meaning players who all have Win Contributions of .000), you could expect a winning percentage of roughly .603, or a seasonal record of about 50-32. On the other hand, if a player's Win Contribution is "-.500" that means if you surrounded that player with a roster of average players you could expect a winning percentage of roughly .433, or a seasonal record of about 35-47.
The Bucks Total Win Contribution from every player adds up to -1.096. The Bucks current Total Player Minutes (53 games * 48 minutes/game * 5 players) = 12820 minutes
MILWAUKEE BUCKS ESTIMATED WINS CALCULATION
Step 1: -1.096/48 = -.0228
Step 2: -.0228 * 1.621= -.0370
Step 3: -.0370 + .104= .0669
Step 4: .0669/48 = .0013
Step 5: .0013 * 12820 = 17.89
ESTIMATED WINS: 18
ACTUAL WINS: 19