The very act of extrapolating how a person would perform based on a brief snapshot in time seems flawed. It is unreasonable to task the interviewer with making a good decision with barely any data.
I used to think that a well calibrated question bank or interview style could be a reliable signal. But the moment you ask something specific is the moment you don’t ask everything else. A poor performing but good candidate’s strengths could lie in the latter category and a well performing but bad candidate’s strengths could be in the former.
There needs to be a reliable and credible way to learn about a persons strengths and weaknesses based on their track record.
I’d weight credible reference checks, previous projects and credentials more than their actual interview performance.