What Makes an In-plant Successful?

I can understand my colleague's desire to arm himself with articles and studies showing that in-plants give their respective associations the biggest bang for their buck, but I have to doubt if such a thing even exists. A study or document, free from the writer's agenda, that shows, once and for all, that in-plants do a better job than commercial printers? I think not. We have advantages and we should be more efficient, but the painful truth is sometimes we don't do as good a job as our commercial brothers and sisters, and sometimes our prices are higher.