The logic behind Marginal Win Score (in a nutshell)
Marginal Win Score is really someone else’s research and rigorously tested professional work (Professor David Berri’s) amended by me based solely on some logical inferences I made and then tested. I lay them out here. If you buy into each of the premises, then the validity of Marginal Win Score follows. If you do not, then it falls apart. Pretty simple.
David Berri’s scientifically tested and peer reviewed work correctly identified the correlation between each of the traditional individual basketball box score statistics and team wins.
Professor Berri’s Win Score metric, a product of the above referenced work, accurately weights each of those statistics according to its impact on win production.
At all times in the sport of basketball there are two participant teams and ten opposing players all competing to win the given contest.
If Win Score is accurate, then the team that produces the highest Win Score in any given game should have the higher probability of winning that particular game.
In the course of a normal basketball game, every player on both teams has the ability to simultaneously: (a) produce “Win Score” for his team; and (b) take actions that make it more difficult for the opponent players to produce “Win Score” for their teams (by harassing shooters, or obstructing the path to rebounds, or making passing more difficult, etc.).
In general an individual player can have the largest individual impact on the production of the opponents that play the same position as him.
Therefore a basketball player’s ability to produce wins for his team is a function of his ability to outproduce the opponent players who play the same position as him, and since the Win Score metric accurately calculates favorable statistical production, then it follows that a comparison of the player’s Win Score per 48 with the Win Score per 48 average of all his counterpart opponents provides an accurate measurement of the number of wins the player produced for his team (when coupled, obviously, with the player’s minutes).