“Hard work” in the context of phd studies is not measured in a number of hours one works per week. It’s measured in a number of first author publications in top journals/conferences.

Which is really really correlated with the number of hours you put in. Hard work means working hard, whatever context you’re imagining.

Let’s assume this is a CS PhD (so no “lab” work). Is this person doing 60 hours of actual research a week? If I did a PhD while working full time, I would expect to do purely research. I’m not interested in teaching or grading papers or anything non-dissertation related.

Btw, this is how most people do their PhDs here. It’s a quick in and out 3 year seal-team like operation. Caveat: We see Ph.D as a degree you do after a 2 year Masters degree. So in total 5 years after undergrad.

When I was in grad school (Econ, not CS) teaching, etc., was less than 10h a week. The rest of the time was research. So yeah, 60+ hours of actual research a week.

That seems... excessive? 60 hours a week / 5 days a week is 12 hours a day. Even working Saturdays, that would give you 10 hours a day 6 days a week. I personally have never met any single PhD student who did that amount of pure research each week for 5 or 6 years. Again, I'm not talking about "lab" type research.

Where is this?

Often more than that. During the dissertation phase 16 hour days almost every day can be common.

It is brutal. It can be worth it, but it is brutal.

What productive thing could you do 16 hours day? Study paint drying in a lab?

Typically not one specific activity, but a slew of different activities all pointed towards the goal.

An example:

8AM - wake, prepare for day, take bus to campus

9AM - teach class

10:30 AM - office hours, grade, read relevant papers

12:00 PM - short lunch window

12:15 PM - research, write code, notes. Short intermittent breaks. Library visits. Seminar attendance / prep, seminar/journal reading, prep, etc. Consult with advisor, others

7:00 PM - break for dinner, bus home

8:00 PM - research, write code, notes. Short intermittent breaks. Seminary reading, journal reading, etc. Class prep.

3:00 AM - sleep

Weekends were similar to weekdays without class or bussing.