The one element no one ever accounts for is the interviewers. You're never going to have a perfect technical interview because you're an imperfect human. You're incapable of judging whether someone is a perfect cultural fit, and someone who doesn't fit the culture might help the company more than someone who does.
That isn't even getting into the the conflict between whats good for the company and whats good for you.
When Google pushed out their interview-results data this year, one of the big findings was that there is NO SUCH THING as a good interviewer.
To quote the NY Times interview with Laszlo Black of Google - "Years ago, we did a study to determine whether anyone at Google is particularly good at hiring. We looked at tens of thousands of interviews, and everyone who had done the interviews and what they scored the candidate, and how that person ultimately performed in their job. We found zero relationship. It’s a complete random mess, except for one guy who was highly predictive because he only interviewed people for a very specialized area, where he happened to be the world’s leading expert."
That being said, there are a lot of very disorganized interviewers out there, especially among seed stage companies. I've been amazed about how many people grumble about the "talent shortage", yet regularly miss interviews with "hot" candidates because of meetings, forget them altogether, or just lack a sense of urgency & speed when it comes to running an effective hiring process.
A large part of having a hiring culture is about decisiveness. Loosing a fantastic Engineer because you spent 4 weeks making up your mind, or you didn't want to pay an extra $10K/year is just silly when it means that you won't hit your product roadmap goals.
I think that is perhaps telling. Google doesn't interview you on your experience, but whether you can can solve network/graph algorithms taken from Knuth exercises. I would expect a random mess from that. It sounds like this person actually drilled down into what the candidate actually knew.
I think it is far more useful to ask somebody about what they actually did. Are they excited and engaged by it, did they come up with novel thoughts about it, do they understand the CS literature in relation to it, and so on. Program a hash table on the whiteboard when you have been just fine using the built in one in your favorite library or language? I'm not sure what that predicts about my on job performance. If I had to do that I'd reread the literature and then whip one up, easy peasy. I can state that with confidence because I read the literature on other topics and do that every day. Have me explain the new numerical filtering technique I just implemented and I'll give you good interview. Ask me to implement a smart pointer? Not so much.
This doesn't make sense to me on first read. I'm unaware of a labor law that requires you to interview people without college degrees. Care to elaborate?
I may have worded it wrong. A large swath of programming jobs do not require a college degree, and in those cases it's illegal to require one. This is why job ads will say, "Desired: College degree or equivalent experience." They don't describe it as a requirement for a reason.
If you design your interviews to focus on knowledge and abilities taught in college, you tend to cut out people without college degrees who don't have the personal grit to go teach themselves those subjects. Since most people don't care for academic learning, this effectively requires a college degree in general.
That said, the big G does hire a number of people without degrees, I hear.
That isn't even getting into the the conflict between whats good for the company and whats good for you.