What to say when evaluating an employee on initiative?

if they take the initiative try to give examples of when they have done that. If they don't then try to tell them you'd like to see them take more intitiative and give them examples of how they can or give them a project and tell them how you'd like them to take the intiative. Give them a situation and talk about that; that way it does not feel like you are attacking them and they will not be defensive.