This is a really stupid question, but I'd thought I would ask anyways. I know that various programs (depending on the specialty, of course) don't fill all of their spots. My logic tells me that programs would what to fill all their spots. Is this true? Or do some programs simply don't fill all their spots on purpose (program X has 8 spots but will only put 6 residents there and leave 2 unfilled)? And if they do purposely not fill all the spots, why?