2. Are they hungry, humble and smart? You need all 3. If they have only 1 of 3 qualities, that's a big problem!
3. Do they light up about the position? If they aren't excited about the position now, they will likely never be excited about the position.
4. Do they follow your instructions precisely during the interview process? If they don't, it's an indication of things to come.
5. Do they show intellectual curiosity or ask a lot of questions during the interview process? If they don't, they will likely fail because of lack of passion and desire.
6. Does this salary meet their needs? If they are taking a pay decrease, can they afford to pay their bills? If they can't, they will leave for a higher paying job ASAP.