I just wanted to share a bit more - this one is more something I am starting to believe from looking at player skills rather than something I modelled, though. As I get more and more data, I am starting to believe more in the idea of sub-levels on potential. This is tough for me to admit, since I have been adamantly against them for a long time. But hey, even smart people can get things wrong sometimes. ;-)When I talked to Joseph Ka, he said something that I thought was interesting: that if sub-levels do exist, maybe all-time great is just a limit case of hall of fame potential. I also heard of a rare potential called "BB developer". I assume that would be the opposite (ie: a limit case of announcer). In order words, something like this:BB developer = 0 (which possibly means capped no matter what)announcer = 0-1bench warmer = 1-2role player = 2-36th man = 3-4starter = 4-5star = 5-6allstar = 6-7perennial allstar = 7-8superstar = 8-9MVP = 9-10hall of famer = 10-11 all-time great = 11 (which possibly means never capped)Anyhow, I do not know anything for sure yet, but if true it seems pretty interesting.
Just found this:(29708.11)Your first conclusion was already known!
One last thing, which you probably already know -- the model for skills is multiplicative, which means that any regression you want to run should have the logs of skills on the right-hand side.