Originally Posted by OrangePower
Actually, no, you have convinced me, so I recant
I think our disagreement centered around the transformation between tennis score and ELO score... your example illustrates your position well. I'm not convinced that such a transformation (or any similar transformation even if non-linear) is valid in terms of the results it produces, but you've convinced me that it could well be the way USTA does it.
I've played some in the past myself, so perhaps if we have any further disagreements we can settle them over a combined chess/tennis challenge
Then all we need to agree on is how to weigh the results!
hey, i like you already!
back in the days we used to have triathlon of sort: tennis + speed chess + well, 'drinking certain substance that made you play either sport rather challenging'
and yes, there were heated discussions on how to combine the score and how to assign weight to each activity. It still brings tears to my eye.
i completely agree that applying ELO to any competition is sort of an art. While it gives you a very well formula to calculate the results you still need to figure out what makes the most sense for input values. For example, i would not be terribly surprised if one found a close correlation between the length of the tennis match and the relative strength of the opponents. So it very well may be that the length should be used as a criteria. like 'if 4.5 plays 4.3 the expected length is 1h45min'. The possibilities are really endless.
Incidentally, since we have touched on doubles vs. singles too. there are other algorithms used in on-line multiplier gaming that supposedly are better than ELO is assessing rankings of the players involved. These concepts are more applicable to doubles in tennis as players may play with different partners, against varying sets of opponents.
glad we could have a nice discussion.