ongoing debate. I don't have the answer and am not sure it is easily verified either way. You could probably find a few threads on this topic on the Theme Park and Attractions board. Here is one but there are others:
http://www.disboards.com/showthread.php?t=3072925&highlight=crowd+calendar+best
One thing I do know is that when we usually go the crowd calendars show an 8. I don't think I would know what to do with a 3 or a 5 crowd day
If you really want to confuse yourself or maybe have a tie breaker,
Undercover Tourist also has its own version of a crowd calendar.