Whatever you do, don't drag it out. If you're not happy with their performance, let them go. For future candidates, pay them to come in and do a short project.

Whatever you do, don't drag it out. If you're not happy with their performance, let them go. For future candidates, pay them to come in and do a short project. That way you have a better chance of getting the right candidate, without committing yourself to full employment prematurely. If you're not happy with their performance, surely this isn't unknown to the rest of the company. It's not good for morale (theirs or yours) to keep this person on. EDITED: clarity