> The challenge is simple although a bit time consuming.
This is really the problem though. You can't ask an interviewee to do anything too time consuming if you want senior people, who often have kids or are otherwise busy.
We ended up explaining the challenge and giving them access, plus up to two weeks to submit. (We’d always give more time if they asked).
They could do it whenever on their own time, and then we scheduled a 1 hour time block to review their code. Some people took an entire weekend, some people took an hour. Sure people are busy but at least this method also gives them the opportunity to see if they’d like to do the type of work we do, as well.
Overall ended up with really great hires who seemed to enjoy the challenge.
An interview process is successful if you hire candidates which turn out to be a good fit both ways.
An interview process is fair if you don't exclude any candidates that would have met the criteria if not for the lousy interview process.
While you seem to be enjoying the former (for now), you are intentionally or accidentally narrowing the pool, and mistreating a number of your candidates.
If intentional, the word will get out, even if it takes a while. If accidental, I hope you work to improve the process.
This is really the problem though. You can't ask an interviewee to do anything too time consuming if you want senior people, who often have kids or are otherwise busy.