I agree this shouldn't be the only component overall, you need to see if he fits into your team but I feel like if he can solve a problem in a timely manner tha

I agree this shouldn't be the only component overall, you need to see if he fits into your team but I feel like if he can solve a problem in a timely manner that I deem moderately difficult using google and some experience based tricks with me looking over their shoulder then I can judge if they are a good engineer. Everyone I've hired using this method has never been fired for incompetence or issues with their skill. My issue is judging peoples personality and team fit. I still have yet to find a solid solution to this and asking Microsoft interview questions or how linked lists in C work isn't going to do that either. People are often overly nice/fit for the first few weeks/months but then go downhill from there as their true personalities show. I see no way to judge this other than calling contacts/past employers and even that doesn't always work.