This is really big; we've been using the same basic "is this person a big phony" set of questions for a long time, and it immediately filters out people who just have no knowledge. Stuff like what is a Boolean variable, what is ssh, what is asymmetric encryption, name 3 hardware components of a server, what is a primary key, etc. I've seen people with resumes full of tech jobs that fail at all of these. And I don't mean slightly off, I mean no clue at all. We don't require a perfect score or anything, and recognize language barriers, but it becomes super clear super quickly when someone is just bullshitting.
We used to call it the elevator test: can a candidate navigate the elevator and make it to the interview. Partly because we got ghosted a few times, but mostly for the number of interviews where we'd sit candidates in front of a PC, show them some code in the language we were advertising for, and say "add a trivial function". Make a button show some text level. The failure rate was a bit terrifying for "2-5 years experience with X" programmers.
I stopped bothering with questions before that point, I'd read their application, look at their resume, then get them in to play with a computer. The good news is that it actually found the people we needed, the bad news is we never found an effective way to pre-filter the ones who couldn't (and even a couple who said "I've never seen this before" when looking at the code!!)
This is really big; we've been using the same basic "is this person a big phony" set of questions for a long time, and it immediately filters out people who just have no knowledge. Stuff like what is a Boolean variable, what is ssh, what is asymmetric encryption, name 3 hardware components of a server, what is a primary key, etc. I've seen people with resumes full of tech jobs that fail at all of these. And I don't mean slightly off, I mean no clue at all. We don't require a perfect score or anything, and recognize language barriers, but it becomes super clear super quickly when someone is just bullshitting.