It depends on the population and several other factors. Earlier this summer we were probably AVERAGING 13+ inches on our crankbait crappie with very few short fish. Recently in the same areas it has been just the opposite.
I think the crankbait is more a large fish bait than most other baits since we target the more aggressive fish with it. Noting finesse about a 10 inch crappie hitting a 4 inch long bait. I have caught crappie as small as 6 inches on Bandits and c55s. The bait looks almost as large as the fish and it is often hard to tell if the little guys are on the bait.