A fundamental component of my research work is the close collaboration with a large number of scientists from all around the world. This is the result of the very large scale of the experiments that are necessary to investigate the structure of matter at the smallest distance scales: building and operating those machines to collect the data and analyze it requires scientists to team up in large numbers - and this builds connections, cooperation, and long-time acquaintance; and in some cases, friendship.
However, even with friends or close collaborators, it is sometimes difficult to provide unrequested feedback - when we see that something could be done in a different way. As long as the issue is of purely scientific nature criticism is usually very welcome and does not generate bad feelings; but sometimes, the issue has to do with soft skills that are ancillary to scientific research, and in such cases it is much harder to pass on good advice: your colleague may rightly feel that you are straggling into territory that is not your own, or perceive that your comments indicate you feel superior or look down on their behavior, and resent it. 

The easy solution is to keep your mouth shut. A harder solution is to always speak your mind: at least your colleagues will know you just can't keep your thoughts to yourself in all circumstances, and will probably pardon the one time they are the target of your criticism. Being outspoken, however, is not something you can engineer or tune to different situations; and it comes with a price tag of its own. I know it because I have been that way for most of my scientific career (well, I have run a blog for over 20 years now!, and over time I have poured into it far too much of my thoughts, often with undesirable consequences). But is there another way?

Well, let us try this one out: instead of talking to my colleague and pointing out what I perceive as a mistake on his part, I will write a letter to a unnamed colleague here, expressing my thoughts freely as if I were speaking frankly to him about the issue I pose. Besides not naming him, I will need to modify some of the details that bring me to having insight on the matter at hand, but I hope this will be a minimal touch.

The letter will probably not reach the intended target (but it could), so a minus effectivity point has to be counted; but it will on the other hand reach potentially several other colleagues who behave similarly. The net outcome should be positive, as nobody will feel offended, and some will find useful food for thought here. Mind you, I do not pretend that my view on the matter I am going to touch on is "the correct one"; there may not be such a thing anyway. But raising awareness is always a good idea in this case. So here is a letter to a unnamed colleague, a full professor who asks for too much from his PhD students. I will call him Seymour, as I don't know any Seymours in the capacity of physics professor.

Dear Seymour,

I hope this finds you well. We haven't spoken much after my recent visit to your institute, and that is a shame as we are working on very similar topics and we might try to collaborate more in the future. However, this letter has nothing to do with that.

I am brought to write to you by having obtained, without actively searching for it, information on the experience that graduate students have when they work in your group; information that tells me you probably might benefit from talking about it with colleagues, or just thinking a bit about your supervision practice, in the hope that something can be improved. 

It goes without saying that I do not speak from any podium, nor do I claim to having anything except common sense to share on the matter, plus of course a little bit of experience from my own supervision activities. In truth, I believe you have supervised many more students than I have, in your brilliant career as a physics professor; yet I have the feeling that my past trajectory -perhaps the very fact that my numbers are smaller - has brought me to pay more attention to good supervision practice than you do. 

Your group produces an impressive scientific output, and I bet you are proud of it. That should be the full measure of a physics professor's success, and of his or her value to our community and to society as a whole. Or should it? 

That rhetoric question is possibly the heart of the matter, because I have the feeling that you would be monolithic in answering it in the positive. You might base this on the fact that we are physicists, and although there is no Physics analogue to the Ippocratic oath, we all follow an implicit oath to do all we can to improve our understanding of Nature. 

But we are just individuals in a large system, and as brilliant and cunning as we are, our direct contribution to humanity's knowledge through the output of our own research is bound to remain rather limited (there are exceptions, of course, and they are what probably motivated us to study Physics in the first place, but we also have to be realistic and accept we are not going to be the next Einstein or Fermi).

On the other hand, there are other ways that allow us to contribute to the advancement of scientific knowledge. And a very important one is by educating our young students and form them as successful scientists. Perhaps one of them may become an Einstein or a Fermi one day: having provided them with the inspiration and the stamina to succeed would then be much more important than all the publications that bear our name, at the end of the day. Think about it: if you supervise 100 students, there is a big chance that two or three of them will do something very significant as mature scientists. But even if none do, by passing on to them your scientific vision, your values, and your method will in the end have a larger impact to society and to scientific knowledge than your own direct research.

A Ph.D. in Physics is, I am sure you will concur, a very demanding occupation for a young guy or gal. As young adults there are tons of things they would enjoy doing more than sitting in front of a terminal to code stuff, or at the blackboard to solve problems: partying, vacations, sports, sex, pizza!, you name it. We ourselves went through that self-depriving experience; regardless of whether we breezed through it or struggled with it, we well know it is hard. There is fierce competition from our peers and pressure to deliver, there are exams and deadlines. 

A large body of literature has examined the psychological issues faced by Ph.D. students; I believe 10 to 15 percent of students experience this in a way that require medical attention. Because of this, there is an increasing demand from higher education institutions (I am thinking, e.g., of the Marie-Curie Actions of the EC, which supports excellence in supervision in their Ph.D. networks) for good supervision practice, creation of non-toxic work environments, care for the well-being of the students.

In the face of this, I have often seen cases where professors are easy-going and collegial with peers, yet run very tightly managed, deadline-driven groups when it comes to students. I am sorry to say it, but your group has been depicted as a publication-centric workflow rather than as a place where free research is conducted. Profit, of course, is number of publications and not money, but the differences end there. Researchers should not feel they are cogwheels, their work environment should not be a production line but rather a place where each can find their motivation and inspiration.

This has probably good consequences in terms of the sheer scientific output, but it also de-motivates the students, makes them feel less important as individuals, and ultimately plays against their development as accomplished scientists. I think it is a mistake, and one that could easily be avoided. Think about it: give them a bit more slack. Let them develop in directions you don't consider "most profitful", for their own sake. Allow them to spend time off and miss a deadline or two without it being a big deal. It will pay off. I try to do it with my students, and the feedback I get from them is absolutely positive. In my experience, allowing flexibility and ownership tends to improve motivation and independence. In other words, there are other components to the utility function we try to maximize when we hire a Ph.D. student.

I am not sure this letter will make you change your attitude much, but I have to let you know that I feel you are making a mistake if you focus too much on the science. So, please think the matter over with care. You are a full professor, so your career can allow for a decreased throughput, can't it? For your students, having more published papers is of course important, but it is more important that they feel they own those papers by having wanted them themselves, rather than having been pushed to produce them; and that they grew as scientists inside your group by having the chance of following their own independent thought rather than working on the assignments they were given.

I trust you will not be upset by these lines, and I leave you by confirming my admiration for your high value as a scientist.

Best regards,
Tommaso