1. For what kinds of jobs would it be relevant to look for a candidate who behaves confidently in a job interview?
2. When conducting job interviews, how can you increase the likelihood that you are evaluating relevant job skills, not just deciding who is most persuasive?

Employers intend to pick the candidates who will perform the best on the job, but often they may be picking the candidates who perform best in the job interview. According to an experiment conducted at the University of California at Berkeley, people assume candidates are competent when they behave with confidence, whether or not they actually demonstrate competence.
In the experiment, people were assigned to teams of four to solve math problems. The team members gave leadership roles to the member who dominated the group by speaking with confidence, declaring opinions more often, and using body language that signaled certainty. Whether or not that team member had the best math skills, the team members rated that person as highly competent.
Applying that experiment to employee selection, it's important for an interviewer to sort out whether a candidate is simply speaking with confidence or actually providing evidence of competent behavior. Unless the job requirements focus on an ability to inspire confidence, the candidate's assertive behavior may not be the most important trait to measure. Instead, the employer probably needs to base the selection decision on more objective criteria.