I started in a new company about 2 months ago, and for circumstances that I won't go into, I need to hire (actually, replace) an employee. Among other skills, the role requires critical thinking and attention to detail - two traits that the incumbent has had formally and informally documented as areas of improvement since their first performance review 3 years ago. I have tried every tool in my arsenal -- short of flatly saying, "You are going to lose your job" -- to try to help them improve in these two essential functions of the role, but they just aren't improving, and I, my boss, and HR are getting frustrated with their lack of progress and empty "I'll do better"s.
So my actual question: When I have to inevitably hire for this role, what are your tips in really vetting these two skills in the interview process? It's one thing to say, "give me an example..." but those questions always ring a little hollow for me. Is this one of those demonstrable tasks (aka, the dreaded "take home project") situations?
The only thing I've come up with so far is asking for the applicant to describe how they devised a process to help their understanding and execution of a confusing or complicated task (but, I'd word it more friendly than that).