How could interviewing board decide the capabilities of a candidate in a short span of one hour duration?

First of all, I think the interviewer must pay attention not to be cheated by the candidate. There are lots of candidates that are simply too good at selling themselves. Than, he should pay attention to the answers the candidate gives. Many candidates have answers prepared for each question, so, I guess that for questions related to professional experiences,  the interviewer should ask the candidate to present one or two more stories that can support his affirmation. Than, you should realize if the candidate is just inventing stories or he really has some good experience behind. Also, the body language should tell you if the candidate really means what he says or is not completely honest. Anyway, you should put the candidate in a bit of difficulty in order to see how he deals with unespected and stressful situations