I prefer to have a 1:1 interview as it makes me more comfortable in knowing whom i am going to deal with. during this interview i study the personality & the attitude & last the knowledge of the candidate, because i believe we all have something to learn still, no matter what my experience is, still i have to learn more. although there is a paper test the candidate has to go through, but that doesn't mean he might not get a chance, unless he is zero background & doesn't accept to know more than what he knows, in that case it's no way to hire him