Alzrius
The EN World kitten
As others have noted, the class-level system that D&D uses is problematic, since it requires that certain things be bundled together with certain other things. You want more skill points? Fine, but you need to take more Hit Dice, more base attack bonus, and more saving throw bonuses. Oh, and we'll also throw in these non-refundable weapon proficiencies; I hope you like battleaxes!
That said, the only real measurement that D&D (in the last few editions) has for non-combat ability grading is in skill ranks. Ergo, higher learning would presumably be measured that way. Luckily, it's comparatively easy to bump up skill ranks (scroll down to the "Knowledge and Crafting" header).
That said, I'd caution against tying this to actually having a diploma. Character stats are usually meant to represent personal ability, not professional recognition.
That said, the only real measurement that D&D (in the last few editions) has for non-combat ability grading is in skill ranks. Ergo, higher learning would presumably be measured that way. Luckily, it's comparatively easy to bump up skill ranks (scroll down to the "Knowledge and Crafting" header).
That said, I'd caution against tying this to actually having a diploma. Character stats are usually meant to represent personal ability, not professional recognition.