Based on the experience I’ve had in interviews, I think what makes them effective is when the interviewer is familiar with the interview guide, knows enough about the role to answer questions, and has a friendly attitude. Other than those I’ve been in contact with leading up to the interview, the interviewer is likely the first person I’ve been given a chance to meet face to face. If they say or do something that shows they aren’t interested in interviewing or clearly don’t want to be there, I think it can send a negative message. It’s always expected to ask questions about the role and the organization after the interview and if the interviewer can’t answer them, I think it can be concerning because you’re not sure what you’re walking into if you accept the role. When they can answer my questions, it makes me more confident that we are on the same page about what exactly the role is and that we have a common understanding of what the expectations are. Something I’ve also experienced in during interviews is if there is a common question about the role that I don’t ask about, they’ll bring it up to give additional information. It is nice when this happens only because they want to give that extra information because they see it as worth mentioning, even if I didn’t bring it up initially.
I don’t think I’ve had an interview where I thought it was ineffective, but I think not knowing enough about the role, not being engaged in the interview itself, and being rude can hurt the effectiveness of the interview. People always say that first impressions play a major role in determining if you get the job, and even if that first impression is negative, the interviewer should still remain polite and interested in the conversation.