Game Design Fragments: Layered stats

DISCLAIMER: I'm not the best game designer out there, however I often come up with interesting ideas. I don't mind if you take an idea of mine and use it in a game of yours, however I'd love to know of any games that use any of my ideas. A credit line like idea based on the thoughts of Nuno Silva (Little Coding Fox)" would be nice too, although it is not required. I hope you find this information helpful.

Layered stats

We could have layers of stats, instead of the usual RPG stats. For instance, having a high confidence stat should increase both agility, precision, and speachcraft. So you'd have on the top layer, "Confidence", and on a lower layer "agility", "precision", "speechcraft".

Increasing a stat would automatically increase the upper stats related to it (so increasing either agility, precision, or speechcraft would increase Confidence too), and increasing a upper stat would increase all lower stats. (If you're confused by what I said, upper/lower means higher layer / lower layer)

This is interesting because increasing a lower stat would increase the upper stat, but would not increase all other stats of the same level. So the most expensive equipments for role playing games with this kind of stats would be those that increase the top-most layer, since it would increase all other stats.