“…If you take a range of novice to expert … [sys]admins and put them in a class room and ask them a set of questions, there is a surprising small delta between the performances of these [sys]admins (it exists but is not as large as one would expect). But when you take these same [sys]admins and put them in front of a computer and ask them a set of questions – the delta in performance is HUGE.”
from the PowerShell blog