Origins uses a system which I call "Persistent Scaling."
Essentially, the game has the capability to scale around your level and adjust encounters, but it does not do so in a way that means the challenge level never changes. Some areas are harder, even at the lower end, and others are a bit on the easier side.
Better, the game remembers when you visit places, so if you are having trouble with a particular encounter, you CAN leave, tackle a few side quests and come back tougher and know that the game won't have suddenly jumped the difficulty up on you to match. Hence "persistent."
It's a very refined system. Some creatures are handled specifically, even. *cough*dragon*cough*
All the brainchild of the DA systems guys, who are, I believe, Space Wizards in disguise, given the level of awesome they deploy on a daily basis.