As I was conceiving the Table Tennis Database and going through all the ratings characteristics to include, “control” always seemed like an odd one. Speed and spin seem pretty clear. If you run an experiment using two rackets with the same blade and just compare two different rubbers, and use the same stroke to hit the ball, the faster one is the one that produces a higher velocity after impact. And with spin you can measure the rotations per minute (well probably not measure, but you can get a feel for how much spin was on the ball). These characteristics could be measured in a controlled lab. But control is hard to measure or even understand.