There is a very strong bias against devaluing belts in Brazilian Jiu-Jitsu. This is good because it means that when you do finally achieve a belt, you know it’s been worth it.
Here’s a good comparison between belts and academic achievements:
White belt – none yet.
Blue belt – university entrance (matriculation).
Purple belt – first (bachelor’s) degree.
Brown belt – master’s degree.
Black belt – doctorate.