I would consider anytime you are thinking about a work issue as productive time. So yes that includes time i am mindlessly browsing HN while my brain is process

I would consider anytime you are thinking about a work issue as productive time. So yes that includes time i am mindlessly browsing HN while my brain is processing information for me to come up with a neat solution to a problem. But yes managers dont get this when i say i get all my work done during lunch hour.