Originally Posted by corners
But it does suggest a lower level of play than in more recent finals, where AM's have been in the 20s-30s, correct?
Also, Brignacca provides the average AM's for the 2005 Grand Slams in the paper you linked in the OP. For men, he has them as follows.
Would it be fair or proper to add or subtract a surface factor when comparing performances in matches played on different surfaces? For example, Rafa's AM in the 2008 RG final was 34.7%, but that might equate to a 53.0% performance at Wimbledon if we added the difference between the French and Wimbledon AM averages.
Sure, I definitely would think that's fair.
One caveat, though, is that surfaces change over time. The clay at RG in the '90s may well have been slower than it was in '05 when Brignacca got his numbers.
And of course technology changes over time, esp. racquets and strings.
So yeah Rafa's top RG performance should probably be thought of as GOAT-level for clay; so if you imagine the equivalent quality on grass, I guess Nadal's number would be somewhere over 50%.
I wouldn't try to quantify it more precisely than that. Too many variables.
I want to start comparing these AM's that I've posted in distinct pairs -- like comparing two USO finals in consecutive years between the same players. That controls the context and reduces variability in factors like surface, which is definitely a major factor to consider when using AM's.