Originally Posted by krosero
Yes, since you gave more UE's to the semifinal than Wimbledon.com did, your AM's for the two matches are already very close. And the AM's would be even closer in the hypothetical scenario in which Murray returns only as well as Djokovic did, and we drop 5 UE's from the final -- but I think there are a few problems with that last step.
In your stats Murray made 4 fewer UE's on the return than Djokovic did. And if we're asking how many of the total UE's in the match resulted from Murray's superiority over Djokovic as a returner, those 4 fewer UE's have to be accounted for.
So if Murray's extra returns in play added 5 UE's to the final, his returning also took away 4 UE's. For all intents and purposes that cancels out any effect on the AM's, as far as Murray's extra returns go.
And the UE's that Murray avoided making on 4 points, at least in your count, are certain; the 5 UE's that he added over the course of the match by getting extra returns in play are hypothetical. Most of those extra returns would have been on serves that normally caused forced errors, rather than UE's (that has to be true because the vast majority of the return errors in the match, by anyone's count, were forced).
So I go back to the arguments I made above. If the receiver gets a tough, forcing serve back into play, a common result is for the server to be shocked or thrown off balance, and forced into an error. We're extrapolating our UE's based on the total % of rallies that ended in UE's, but a rally that starts with a tough serve unexpectedly returned is not a typical rally. The % of such rallies that end in UE's could be very different from the overall %.
So the 'extra' UE's produced by Murray's returning could be 5, or perhaps only 2 or 3. And Murray avoided making UE's himself on 4 returns: so I think even going with your numbers it's a very difficult argument to make, that better returning can produce lower AM's.
well, the receiver being forced into error when a RoS is made on a medium-tough serve is one scenario .... but the same scenario is applicable on other kind of serves ....
it could be that on a medium to tough serve, the return is 'neutral' and ensuing rally may result in a UE ..
either way, I really don't think there is a 'significant' difference in those sort of returns ..
one thing that you are probably neglecting is that when someone returns so many of those first serves, it puts quite a bit of pressure of the server; who'd most probably be forced to go for more and commit more UEs ....
that is more common than someone making careless UEs even while getting quite a free points on the serve
@ the bold part, could be .... but one another thing is the point I've made above ....
Originally Posted by krosero
As far as slower surfaces, as you say, the % of UE in rallies is larger. So hypothetically a receiver who gets a lot of tough first serves back into play can end up inflating the total number of UE's in the match.
However, the same objection there: on slow surfaces, serves do not force errors the way they do on fast surfaces. And the players themselves don't necessarily serve all-out the way they do on fast surfaces. There are more opportunities to make UE's on the return. So a player who displays superior returning skills should also be reducing the UE's in a match when he gets easy/moderate serves back into play, thus raising the AM's.
yeah, fair point ... might actually want to apply this on a couple of examples to really 'test' this ....again the point I've made in the first part is applicable here as well ...