You could gain consistency of evaluation; being a lot clearer about the #1 thing you're looking for; hiring faster; paying for hiring costs.
There must be some reason a candidate is rejected. Putting the reason down in writing makes you accountable to the role, to the company, to the ideal candidate, and to the candidate currently evaluated.
Posting a job and not hiring until 6 months later doesn't make the hiring manager accountable.
To protect from legal liability, require candidates to sign something that clears the company from legal liability. Companies make candidates and employees sign all sorts of NDA/non-compete/etc documents anyway.
Writing down the reason for not hiring someone is helpful. Sending it to them isn't.
The reason is almost always "they did not appear to be good enough," usually around coding or problem solving. Very rarely is it something else.
I do prefer to give feedback, and so does our recruiter, so a lot of our candidates get feedback. But honestly I'm not sure how useful it is, being mostly "we have a high bar and they didn't reach it." The truly valuable feedback is how to get better, but that's hours and hours of help.
Plus, one time I did give feedback directly to the candidate over email, and they continued to badger me about it. I'm fine with shutting that kind of thing down, so I still give feedback, but it did sour me a bit.
You don't know that across all candidates. And you can get paid for sending it.
"they did not appear to be good enough" is very useful feedback for me compared to no feedback. Especially when my resume isn't even selected to interview. It at least tells me there's competition.
Else I never learn which of the tens of possibilities is generally the reason for rejection. This matters if the reason is something important that I don't know about, like "didn't have same role for at least 3 years."
Doesn't know React. Not enough Javascript experience. No k8s. No professional DevOps. Only 1 year in DevOps. Resume too long. Resume too short. Didn't provide GitHub, must mean he's not a coder. No LinkedIn. Not enough connections on LinkedIn. Don't know anyone from their LinkedIn. No public website, must not be passionate. Too many side projects. Too academic. Not enough research experience in this area. Too much research experience in some other area. Probably likes theory. Not enough theory, probably likes building things. Not a local candidate. No Luigi experience. Not enough Airflow. Hasn't used MySQL for a while. Hasn't used ClickHouse. We started interviewing. No consistent job titles. Too generalist. Too specialist.
Candidates can deposit a fee as promise they won't badger the interviewer. They get the money back after a year if they don't badger or lose the deposit. This might make interviewers less sour.
I don't think the fee idea is very workable. The interview process already has a high amount of hassle on the employer side. Adding in collecting, holding, and returning some kind of fee is a big addition of annoying overhead.
I don't think there's any way to incentivize giving feedback besides changing the cultural expectation across the industry.
Hard to say - but giving without the expectation of return can certainly lead to future gain. I highly respect the company that did schedule a feedback session and it certainly made them one that I will continue to watch for opportunities rather than just a position opening that popped up on a stream of jobs that I happened to find.
I'd be willing to bet they at least think there is some metric being improved there. Possibly assuming it might garner more interest as a desirable workplace during an staffer's market.
That person doesn't work for your company?