This may not be the place for this question, but its the one place I know where I'll get solid mathematical answers:
I'm looking for a system that ranks event winners, but it can't require everyone to be there. Say you have 30 racers, and only the first place winner is given points, but if only 10 racers attend, how do the ranks of the other 20 racers not get hurt too much? I want to avoid people being able to say: "Well you've got more points because you've raced more times, but I'm still better."
I'll also welcome any suggestions of a more precise question, like an algebraic equivalent.
Sidenote: this is for a game being developed, but not a racing game. It is just easier to get the problem across that way.
I would suggest the Schulze beatpath method: http://www.cohp.org/records/difficulty/schulze.html
The method creates a ranked list by using partial orders voters provide. A race provides a partial order. The method works even when most votes are sparse, which means that they do not rank most participants.