Debate is an activity to see someone’s competence. Two candidates have a chance in competeting each other to make publicaware. In democratic area, debate can be a role model to see people’s capacity as a winnet for public’s vote.
How to see that someone is better than another. It is up to choice and our respect to him/hers. And survey can tell alot about that.
It is not about a winner itself but also about track record he or she has. We can ensure ourself in taking one that there is no the ideal one to choose without our support in taking one of them.