I understand the goal of this law but don't see how it solves it. I usually ask people what their current salary is now. I want to offer them (at least) a modest raise to come here. I want them to be happy and excited. I also want to not waste a ton of time negotiating salary if they want 50K more then I have available in my budget. You are worth whatever you can get someone to pay you. Some people may come in with a…
I usually respond to this question with a question of my own: "Are you asking this question because you don't have faith in your own ability to interview and value employees or because you are trying to lowball me?"
[Serious] Do you think this is possible? I can think of no way except to put them on a 3 month contract to see what they are really worth and I don't think that is what candidates are looking for.