Originally Posted by amirbachar
Amazingly, today I was thinking of doing the same thing myself.
My thinking is to treat each set separately, so a 2:1 is like a result of 0.666, but the value is doubled by the number of sets * K.
K is the constant of the system. which will be decided by what gives the best predictability to the rankings.
One possible concern in this methodology is would it cause an "inflation" of points over the time.
If we take a match result in sets, then a question is how to treat results in women's tennis, since all matches are played in "best of 2 sets". Should they be treated completely separately, or use criteria for male tennis? That is, treat win in 2 sets as 1, win 1 set = 0.5, or 2 sets = 0.66. The second approach would lead to significantly lower maximal rating for female players, and I think that is not fair.
There is also a matter of selecting a proper K constant. For my calculations I initially put this constant to 24, but there are some systems in chess which use different values for K depending of strength range, for instance higher K for rating below 2000, and lower K above 2000. K constant effectively determines the maximum difference in points that can result as an outcome of a single match.