I've been on several threads talking about this question. In my experience, I cannot see ANY changes that scientists supposedly help with. I've tried many different scenarios to get a change in science (transmitting, recovering, etc.) but I can't see any indication that scientists help and neither can anyone else as far as I've seen. If anyone can get some actual specific data showing changes in their science values through Kerbal scientists it would be much appreciated. Otherwise, I think it is a bug that only works in theory. I hope it is a bug, because in my gameplay scientists have been useless. I don't mean to complain, I just hope I'm either very wrong or this can get fixed soon.