Mucho respect to the OP who was part of such elite fellowships as the "Bar Raisers" and "Hiring Committees" (and I'm sure he would totally have made it into the prestigious "As Appropriate" group at Micro$oft if he only applied for it).

My record is comparatively humble: I hired around 300 people in tech for small-to-medium size companies, in the small tech backwater of Vancouver, Canada.

My conclusions:

(1) Interviewing is an intractable problem. Start by recognizing that.

- You don't interview the best candidates, but the ones with the best resume.

- You don't hire the best candidates, but the ones that do best at interviews.

- Screening by HR (phone or zoom) is at best useless.

- Timed coding assignments are a waste of time. They are used because they're cheap + provide a [generally wrong] "quantitative signal". Noone's job will consist of solving 8 "leetcode" riddles/day.

(2) "Technology fit" is a dangerous illusion:

- It is very, very, very unlikely that any candidate will be able to pick up right away your tech environment. (ok; exception: you're hiring permanent an existing community contributor for your open source project)

- Your best new hires will be 0% productive in their first month (negative; training will use resources); 15% in their second; 50% in their third.

- Rejecting e.g. "Java" when screening for "C-sharp" is stupid.

(3) The interview process is about building relationships.

- People you don't hire will remember your company from the interview + disseminate.

- Someone you didn't hire today (one of your top rejections) may be super-attractive 2 months later, or next week if your top candidate accepted another position.

- Ownership of the process or at least buy-in from the team (vs. just the hiring manager + opaque "corporate committees") is the first step in a working relationship. Your "superstar" may end up being toxic in the team and you could find that out in the interview.

(4) Five simple rules:

- Treat phone/zoom screening like an advertisement for your company. Ideally do it yourself (hiring manager). Largely ignore feedback from HR :)

- Hire candidates who are: smart + hungry. Programming languages; frameworks; environments are secondary.

- Try to get a sense of the fit with the other humans in the team they'll be working with.

- Take "3-month probation" seriously. Explain it to the candidate + team. Sell it internally. Candidate compensation for a botched probation is reasonable + just money, after all.

- Treat candidates as humans: Send a personalized rejection (from you, the hiring manager _not HR_) to everyone who made it to the interview. Call or zoom everyone who made it to the final round. If you can, provide them actionable feedback on ways to improve their interview process. Leave a "human" door open.