People are still bad at gauging their own interview performance
>some portion of interviewees are losing interest in joining your company just because they didn’t think they did well, despite the fact that they actually did.This is the key takeaway for me. This is IMO and experience probably based on a "sour grapes" type defense mechanism, where candidates will internally try to talk themselves out of wanting a job that they felt they didn't get. They walk out of the interview feeling they didn't perform, and instead of regretting the lost opportunity they start to focus on even the most minute "negatives" about the job/company.The more time you give a candidate to stew about those reasons they don't want the job, the more time they'll have to find reasons that may not even exist.Positive feedback should be given almost instantly. Some companies and candidates are reluctant to give positive feedback quickly because they feel it may hurt their negotiation leverage.I don't have data on this, but anecdotally (over almost 20 years in recruiting) I've seen this countless times while collecting post-interview feedback from candidates. The ones that feel they did poorly are likely to mention a negative about the interviewer or company, which becomes somewhat awkward when we come back with a job offer.