Asking technical knowledge questions are important and I've also frequently asked candidates to write some code on the whiteboard, however more often than not you also want to know how candidates interact with others when there are disagreements about technical details and other social or team dynamics so asking them to describe a specific scenario is usually good. This isn't the end of the story though. Decent reference checks where you challenge the referee to come up with reasons you don't want to hire the candidate get you the most powerful information. Will this candidate wreck the culture and dynamics of your team?