We’re a very small team with little experience in hiring but got approval for a new engineer. Basically HR will look for people through the usual channels and I think we have a reasonably good job description. Unfortunately the coding challenge (a 30h+ take home) is atrociously difficult and doesn’t really reflect what we do. On the other hand I think the false positive rate would be low. FWIW it’s a Linux application and it might be difficult to only count on experience from the CV.
Any ideas how to build a good challenge from scratch and what time constraints are reasonable?
There are a ton of good challenges on leetcode. I’d use a [virtual] whiteboard and have the candidate ask questions. When I’m hiring, I want engineers who can ask clarifying questions. I don’t want someone who takes an incomplete set of requirements and goes off and builds what they think is the solution. I prefer they use pseudo code and not worry about syntax. Their IDE of choice would correct the minutia. I once had a candidate ask me if I thought design pattern X would be a good fit for the solution. Excellent question. That shows me they are thinking critically about the problem and open to peer input.
If you go with the programming puzzle type challenge, have a few in your repertoire. I’ve seen candidates totally blank on puzzle A, but rock puzzle B and vice-versa.
Things that have turned me off in interviews:
Good luck on the hiring process!