Good probability of development rating?

When i look at many of the top youngster, they only have probability of development at around 40-50. Is that good or bad?

I assume you mean the value in Genie Scout. It's essentially trash, as so many variables affect it. Do you have good training facilities? Then it's probably 80%, instead of the stated 40-50%. Do you play him often? If not, that might drop down to 60% again. That value is completely useless to be honest, way too many variables.

Alright thanks for the answer