I've seen both usages in articles published by reputable media like NYT and the Entrepreneurs. I've seen both being used to refer to what seems to me to be the same thing. It's so puzzling to me.
An example taken from the Guardian (para 5):
Working culture remains horribly gendered. The report that working full-time increases a mother’s stress hormones by up to 40% puts numbers on ...
So I wonder which one is correct and is there any subtle distinction between the two variants?