This question is a tricky one.
Years ago, I was a Production Manager in an electronic factory and needed an assistant. As I sifted through the applications, I spotted one I recognised. It was from the father of an old school friend. He was massively over-qualified. His last salary was well over twice what we were offering.
Because I knew him, I thought I’d get him in for an interview anyway. He was amazing. He had 30 years of really valuable experience and was clearly very knowledgeable. He was also very nice. But, unfortunately, after 25 years of service to his previous employer, he and all his colleagues received a letter telling them not to come in on Monday.
He said he didn’t really need a vast salary; he just needed an income to keep him going till his pension kicked in. Because of this, he didn’t mind taking a massive pay cut.
My boss and my colleagues thought I was mad to take him on. They were all convinced he would leave in a few weeks and be too old to do a good job.
As it happened, he was still there five years after I’d left. Not only that, but he did a phenomenal job, and I learned a great deal from him.
The trick here is to find out why the over-qualified candidate wants the job. So often, there is a perfectly good reason that makes complete sense. Of course, this isn’t always the case, and that’s why you need to check this area carefully, but you need to stay open-minded. This is the key, don’t just make assumptions about the person and the reasons.