Make sure they're both expected retail price. I suspect Edmunds actually uses Kelly Blue Book. You can also check TruCar which, I think, has used cars and NADA. There is also Black Book but may not be open to the public. One of your sources may be from a different date. I get $5725 retail on NADA but it may not be the same Outback. Cylinders? Trim? The Edmunds price could be trade-in value which is always less by about that much.