Bashiok a posté cette nuit un message concernant le niveau des objets et ce à quoi il correspondait. Les statistiques sur un item dépendent de sa qualité, de son emplacement et de son niveau. Pour une qualité identique et un même emplacement, les stats seront potentiellement meilleures sur un objet de niveau 63 que 62, le budget de statistique étant supérieur (même si un bon objet 62 peut être meilleur qu'un mauvais objet 63) :
Bashiok sur Niveau des objets (Source)
It is one piece of what determines an item's "budget". You can think of an item as a blank slate, and by placing specific labels on it that have pre-determined "costs" the item essentially has a number of points it can then "spend on itself". The game will say "This is an ilvl 63 rare set of gloves". Those labels determine what affixes it can have, its maximum and minimum ranges, as well as damage, speed, armor, etc. Essentially every part of the item is determined by its type (common, magic, rare, legendary), what kind of item it is (head, chest, sword, etc.) and item level. Crafted, Legendary and Set items follow the same rules, but can have set affixes on them that don't change but still have a range to roll.
Item's also have broad ranges, and will overlap. The below concept of that overlap is in no way accurate or indicative of anything at all, except to illustrate the overlap. :)
Completely made up power scale that has no basis in anything:
I'm probably missing something in there, but that's the basic gist. We're working on adding a ton of the more nitty gritty game design specifics to the Game Guide up-top. We're shooting for something not too unlike the old Arreat Summit to detail systems and the inner workings of the game, which should help with this specific question as well.