Here is the skill-scale Camp of Champions uses.
Level 1:
Can easily link turns, rides/skis blue rated runs in the winter. Never ridden a jump, rail, box or half pipe before. Ready to start riding small jumps, rails and boxes, and/or learning grabs.
Level 2:
Comfortable riding small jumps (10 - 15 ft), performing grabs and sliding on “ride-on” rails and boxes. Ready to start learning 180's, tweaking grabs, jumping onto flat rails/boxes, and riding the half pipe by learning kick turns on the walls).
Level 3:
Comfortable spinning 180's on small jumps, tweaking grabs, jumping on rails and boxes and turning on half pipe walls. Ready to spin 180's on medium jumps (15 - 30 ft), learn 360's, jump onto down rails/boxes and getting air in the half pipe.
Level 4:
Comfortable spinning 360's on medium jumps, sliding down rails and boxes, getting air in the half pipe. Ready to learn 540's on medium jumps, grab while spinning, spin on/off down rails/boxes, slide kink rails/boxes, and how to maintain consistent speed and amplitude in the half pipe.
Level 5:
Comfortable spinning 540's on medium jumps, spinning on/off rails, sliding kink rails and boxes, and maintaining consistent speed and amplitude in the half pipe. Ready to spin 540's on large jumps (35 - 50 ft), learn to spin 720's, spin on/off kink rails, start spinning in the half pipe.
Level 6:
Comfortable with 720's on large jumps, spinning on/off both kink and down rails, spinning in the halfpipe. Ready to learn 900's and up, take spins to X-large jumps (50+ ft), switch spins on/off rails, connect multiple spins in the half pipe while maintaining speed and consistently high amplitude.
Guessing level 7 is pro/very good.