I have a ghost++ bot that hosts games of Dota (a warcraft 3 map that is played 5 players versus 5 players) and I'm trying to come up with good formulas to balance the players going into a match based on their records (I have game history for several thousand games). I'm familear with some of the concepts required to match up players, like confidence based on sample size of the number of games they played, and also perameter approximation and degrees of freedom and thus throwing out any variables that don't contribute enough to the r^2. My bot collects quite a few variables for each player from each game:

The Important ones:
Win/Lose/Game did not finish
# of Player Kills
# of Player Deaths
# of Kills player assisted

The not so important ones:
# of enemy creep kills
# of creep sneak attacks
# of neutral creep kills
# of Tower kills
# of Rax kills
# of courier kills

Quick explination: The kills/deaths don't determine who wins, but the gold gained and lost from this usually is enough to tilt the game. Tower/Rax kills are what the goal of the game is (once a team looses all their towers/rax their thrown can be attacked if that is destroyed they lose), but I don't really count these as important because it is pretty random who gets the credit for the tower kill, and chances are if you destroy a tower it is only because some other player is doing well and distracting the otherteam elsewhere on the map.

I'm getting a bit confused when trying to deal with the fact that 5 players are on a team, so ultimately each individual isn't that responsible for the team winner or losing.

Take a player that is really good at killing and has 40 kills and only 10 deaths, but in their 5 games they've only won 1. Should I give him extra credit for such a high kill score despite losing? (When losing it is hard to keep a positive kill/death ratio) Or should I dock him for losing assuming that despite the nice kill/death ratio he probably plays in a really greedy way only looking out for himself and not helping the team?

Ultimately I don't think I have to guess at questions like this because I have so much data... but I don't really know how to look at the data to answer questions like this. Can anyone help me come up with formulas to help team balance and predict the outcome?

Thanks, Dan