That isn't funny. It is sad. I am sure you are not alone though so I will explain. The coefficient of restitution is simply the ratio of the velocity after impact to the velocity before impact assuming the paddle is not moving. Obviously the velocity of the ball after impact will be less than the velocity of the ball before impact. In the Tiefenbacher document this number is about 0.6. I have never seen a setup with a ratio of 0.8 or higher documented.
No they are not. They are the only true rating of the equipment itself. Everything else is just an opinion.
Pathfinderpro did a pretty good job of evaluating rubbers and balls a long time ago. What was interesting is that Pathfinderpro would have two groups of players evaluate a rubber. The higher rated group and the lower rated group had different opinions about the SAME rubber.
https://www.youtube.com/watch?v=-k5SyIn4Ajw
https://www.youtube.com/watch?v=1pY_iHtycaA
https://www.youtube.com/watch?v=O9iuZ0qUXBA
https://www.youtube.com/watch?v=whqwE57M88g
https://www.youtube.com/watch?v=3Mi8bDK83K0
https://www.youtube.com/watch?v=bdACvEvZjRM
https://www.youtube.com/watch?v=43WWRf5yW6M
https://www.youtube.com/watch?v=xilu8C-cQZM
https://www.youtube.com/watch?v=yAECDI-Ruwo
https://www.youtube.com/watch?v=T1E5T7xo57c
https://www.youtube.com/watch?v=FU6cgRuhN28
https://www.youtube.com/watch?v=G5BNkWN9s1E
These are very good attempts at doing reviews.
These videos are old. There is much better equipment now.
My hat is off to Pathfinderpro because I know they took a long time to make.
Yes, so?
No, they are just opinions and feelings. Opinions will not help your play. At this time it is all about marketing. The Pathfinderpro approach is much better.
I have seen too many cases where people think they see or know something but when you get the high speed cameras, data acquisition and recording equipment out they are proven wrong.