Yes.
It is visible on the saving throws rolls in the battle log.
Every level diference means +1 to saving throw. Therfore put a +10 level beggar on the knees by your knock down skill is quite difficult. >-]
I think that every dice rolls are made by 100side dice. e.g. percent. so the attack rates are adjusted same way. That means, attacking an enemy who is +2 levels gives them +20 to defense.
